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Radiation Oncology/Bile duct/Unresectable Disease/Brachytherapy

 * Ohio State 1989-02 ASTRO Abstract Long Term Follow-Up of Patients of Intrahepatic Malignancies Treated with Iodine-125 Brachytherapy (2005 Nag S, ASTRO 2005 #2086)
 * Retrospective. 64 patients (54 mets CRC, 2 mets non-CRC, 4 CCA) treated with permanent BT 160 Gy; R1 59%, R2 41%; median follow-up 13.2 years
 * Median survival (5-year OS): 20 months (5%). Higher for small implants and without prior resection
 * Local control (5-year): median 9 months (22%)
 * Conclusion : "Permanent I-125 brachytherapy is a safe and effective adjuvant treatment for unresectable intrahepatic malignancies. It is a simple technique with morbidity and mortality rates comparable to liver resection alone. Patients considered good candidates for I-125 brachytherapy include those with small volume implants, those without prior liver resection, and those with solitary liver metastases.

 * Bologna Italy PMID 15675480 -- Unresectable hilar cholangiocarcinoma: multimodality treatment with percutaneous and intraluminal plus external radiotherapy. (2004 Golfieri R, J Chemother. 2004 Nov;16 Suppl 5:55-7.)
 * Protocol report. 11 patients treated with bilateral percutaneous drainage + BT + EBRT; 6 patients completed protocol.
 * Mean survival: 10.5 months, better tahn control group with stenting (2.7 months) or drainage (1.7 months)

 * Hong Kong PMID 15918211 -- Long-term survival after intraluminal brachytherapy for inoperable hilar cholangiocarcinoma: a case report. (2005 Chan SY, World J Gastroenterol. 2005 May 28;11(20):3161-4.)
 * Case report. 1 patient. Unresectable hilar CCA survival >6 years

 * Berlin Germany PMID 15525748 -- Liver malignancies: CT-guided interstitial brachytherapy in patients with unfavorable lesions for thermal ablation. (2004 Ricke J, J Vasc Interv Radiol. 2004 Nov;15(11):1279-86.)
 * Phase II. 20 patients (19 liver mets, 1 cholangiocarcinoma) treated with CT-guided HDR. Group A (n=11, liver tumors >5cm), Group B (n=9, liver tumors <5cm adjacent to hilum). Average dose 17 Gy (12-25 Gy). Median follow-up 13 months
 * Severe side effects 2 patients (10%): obstructive jaundice from tumor edema, intra-abdominal hemorrhage. Frequent LFT elevation without clinical symptoms
 * 1-year local tumor control: Group A 40%, Group B 71%. After CT-guided HDR retreatment 93% overall control
 * Conclusion : "CT-guided brachytherapy based on individual dose plans and 3D CT data sets generated encouraging results in large liver malignancies as well as in tumors located adjacent to the liver hilum."

 * Asahikawa Japan 1988-98 PMID 14630274 -- Intraluminal low-dose-rate 192Ir brachytherapy combined with external beam radiotherapy and biliary stenting for unresectable extrahepatic bile duct carcinoma. (2003 Takamura A, Int J Radiat Oncol Biol Phys. 2003 Dec 1;57(5):1357-65.)
 * Retrospective. 93 patients treated with definitive RT. EBRT (50 Gy) + ILRT (mean 39.2 Gy at 0.5 cm)
 * Median survival: 12 months; impact of tumor length, hepatic invasion, DM
 * Mild-to-severe GI complications in 34%, related to length of ILRT and activity
 * Conclusion : "Our combined-modality therapy provided reasonable local control and improved the quality of life of patients with extrahepatic bile duct carcinoma. Because none of the treatment characteristics had any impact on survival or biliary patency, lower dose levels and/or a localized target volume are recommended to minimize morbidity.

 * Yonsei Korea 1986-95 PMID 12909222 -- Combination of external beam irradiation and high-dose-rate intraluminal brachytherapy for inoperable carcinoma of the extrahepatic bile ducts. (2003 Shin HS, Int J Radiat Oncol Biol Phys. 2003 Sep 1;57(1):105-12.)
 * Retrospective. 31 patients with EBRT (median 50.4 Gy), 17 EBRT alone vs. 14 EBRT + ILRT (15 Gy at 1.5cm).
 * Locoregional failure most common, no difference in recurrence rates (53% vs. 36%, p=NS)
 * With EBRT dose >50 Gy, most experienced GI symptoms
 * Overall 2-year survival: 0% EBRT vs 21% EBRT + ILRT (p=0.02)
 * Conclusion : "Given these observations, we believe that the combined use of EBRT and high-dose-rate ILBT is a beneficial, relatively safe, and effective method of improving the treatment outcome in selected patients with inoperable carcinoma of the extrahepatic bile ducts."
 * Graz Austria PMID 12558559 -- Palliative treatment of unresectable bile duct tumours. (2003 Mayer R, Acta Med Austriaca. 2003;30(1):10-2.)
 * Retrospective. 14 patients treated with HDR BT (10 Gy), 5 patients additional EBRT (45-50.4 Gy)
 * Median survival: 6.5 months, BT alone 4.5 months vs. BT+EBRT 6.5 month (p=NS)
 * Conclusion : "Patients with advanced unresectable bile duct cancer face a dismal prognosis; however, biliary drainage, and intraluminal brachytherapy with or without external RT, seem to be able to improve quality of life in the remaining time span."

 * Aachen Germany PMID 12491056 -- Combined external beam and intraluminal radiotherapy for irresectable Klatskin tumors. (2002 Schleicher UM, Strahlenther Onkol. 2002 Dec;178(12):682-7.)
 * Retrospective. 30 patients with proximal tumors. 18 treated with EBRT (median 30 Gy) vs. 12 treated with EBRT (median 30 Gy) + ILRT (median 40 Gy). 24 patients received low dose 5-FU
 * Median survival: EBRT only 3.9 months vs. EBRT/ILRT 9.1 months
 * Significant (p<0.05) improvement in ILRT >30 Gy and patients without jaundice
 * Conclusion : "The poor prognosis in patients with advanced Klatskin's tumors may be improved by combination therapy, with the role of brachytherapy and chemotherapy still to be defined. Our results suggest that patients without jaundice should be offered brachytherapy, and that a full dose of more than 30 Gy should be applied."

 * FNHK Czech Republic
 * PMID 12143240 -- Intraluminal high dose rate brachytherapy in the treatment of bile duct and gallbladder carcinomas. (2002 Dvorak J, Hepatogastroenterology. 2002 Jul-Aug;49(46):916-7.)
 * Retrospective. 13 patients with BD and GB treated with HDR BT via diahepatal drain or PTBD
 * Control of jaundice in all patients. Well tolerated. Mean survival 9.2 months
 * Conclusion : "The addition of intraluminal brachytherapy may be beneficial to patients with carcinomas causing biliary obstruction in whom bile drainage can be established."

 * PMID 12143198 -- Transduodenal intraluminal high dose rate brachytherapy in the treatment of carcinomas of the subhepatic region. (2002 Dvorak J, Hepatogastroenterology. 2002 Jul-Aug;49(46):1045-7.
 * Retrospective. 12 patients with inoperable BD and pancreatic head
 * Mean survival 9.4 months
 * Conclusion : "Transduodenal intraluminal brachytherapy is technically feasible. The addition of intraluminal brachytherapy may be beneficial to patients in whom drainage can be established. Transduodenal insertion of brachytherapy is not competitive to the percutaneous approach but spreads the possibilities of the treatment of bile duct carcinoma. Intraluminal brachytherapy of pancreatic head carcinoma is feasible only via transduodenal approach."

 * Miami 1991-98 PMID 11895206 -- High-dose-rate remote afterloading intracavitary brachytherapy for the treatment of extrahepatic biliary duct carcinoma. (2002 Lu JJ, Cancer J. 2002 Jan-Feb;8(1):74-8.)
 * Phase I/II. 18 patients treated with 45 Gy EBRT + HDR BT (52 Gy vs. 59 Gy vs. 66 Gy)
 * Median survival 12.2 months
 * Dose response suggested: 9 months vs. 12.2 months vs. 20.3 months survival (p=NS), 25% CR/PR vs. 80% CR/PR responses
 * Conlusion : "High dose rate brachytherapy of 21 Gy in three divided weekly treatments, plus 45 Gy of external beam radiation is well tolerated. A dose response is shown with significant increase of PR and CR rate for dose >59 Gy. This modality of treatment appears to be safe and effective for inoperable extrahepatic biliary duct carcinoma."

 * Prague Czech Rep PMID 11462891 -- Intraluminal brachytherapy and selfexpandable stents in nonresectable biliary malignancies--the question of long-term palliation. (2001 Bruha R, Hepatogastroenterology. 2001 May-Jun;48(39):631-7.)
 * Retrospective. 32 patients with nonresectable CA (17 Klatskin, 11 GB, 4 papula) treated with stent implant and ILRT (30Gy)
 * Median survival: Klatskin 11.9 months, GB 7.0 months, papulla 42.5 months. No stent complications
 * Conclusion : "Intraluminal brachytherapy combined with stent implantation is a safe method and appears to prolong survival in inoperable patients with Klatskin's tumor and carcinoma of papilla Vateri compared with nontreated patients in previous studies. In contrast no similar effect should be expected in patients with gallbladder carcinoma."

 * Asahikawa Japan 1988-99 PMID 10884992 -- [Management of hilar bile duct carcinoma with high-dose radiotherapy and expandable metallic stent placement] - [Article in Japanese] (2000 Saito, Nippon Geka Gakkai Zasshi. 2000 May;101(5):423-8.)
 * Retrospective. 107 patients treated with metallic stent and EBRT + HDR BT (59-98 Gy)
 * 2-year (5-year) OS: RT 23% (8%) vs. no RT 0% (0%)
 * Conclusion : "High-dose radiotherapy, consisting of ILRT and EBRT, appears to be feasible in the management of hilar bile duct carcinoma, and it offers a survival advantage for patients not suited for surgical resection. The placement of EMS assists the internal bile flow and lengthens survival after high-dose radiotherapy."

 * Amsterdam 1985-97 PMID 10436826 -- Role of radiotherapy, in particular intraluminal brachytherapy, in the treatment of proximal bile duct carcinoma. (1999 Gonzalez Gonzalez D, Ann Oncol. 1999;10 Suppl 4:215-20.)
 * Retrospective. 109 patients received RT, 71 patients surgery + preop RT (19) or + post-op RT (52). Of these, 41 received 10 Gy ILRT boost. Median dose 50-55 Gy. 38 patients palliative RT, 19 received 22-25 ILRT Gy boost. Median dose 60-68 Gy.
 * Median survival: surgery + RT 24 months vs. palliative 10.4 months
 * Surgical patients: dose > 55 Gy had *lower* survival, and no benefit to brachytherapy
 * Palliative patients: no benefit to brachytherapy
 * Conclusion : "The role of radiotherapy either as adjuvant or as primary treatment remains to be demonstrated in prospective randomised studies. From our results, it seems that high radiation doses could be dangerous and could detriment prognosis. Brachytherapy boost was not superior to treatment with external beam irradiation alone."

 * Turin Italy 1980-96 PMID 9824998 -- Interventional radiology and radiotherapy for inoperable cholangiocarcinoma of the extrahepatic bile ducts. (1998 Milella M, Tumori 1998; 84:467-71.)
 * Retrospective. 130 patients treated with palliative percutaneous transhepatic biliary drainage (PTBD), 19 excluded after short PTBD survival (<30 days), 111 analyzed. No RT 80% vs. EBRT 9% vs. EBRT + ILRT 11%
 * Median OS: 4.2 months; no RT 3.6 months vs. EBRT 11.5 months vs. EBRT + ILRT 14.3 months
 * Conclusion : "The combination of ERT plus BRT improves survival and quality of life of the patients submitted to PTBD for cholangiocarcinoma."

 * Osaka Japan PMID 9638416 -- Endoscopic irradiation and parallel arrangement of Wallstents for hilar cholangiocarcinoma. (1998 Kubota Y, Hepatogastroenterology. 1998 Mar-Apr;45(20):415-9.)
 * Case report. HDR BT followed by placement of 2 Wallstents in parallel
 * Conclusion : "This endoscopic technique seems to be simple, safe, and reliable in obtaining bilateral hepatic drainage with Wallstents in patients with hilar cholangiocarcinoma."

 * Mayo Jacksonville PMID 9369143 -- External radiation therapy and transcatheter iridium in the treatment of extrahepatic bile duct carcinoma. (1997 Foo ML, Int J Radiat Oncol Biol Phys. 1997 Nov 1;39(4):929-35.)
 * Retrospective. 24 patients, median EBRT dose 50.4 Gy, median transcatheter boost at 1 cm radius was 20 Gy. 9 pts received concomitant 5-FU
 * Median survival 12.8 months, 5-year OS 14.1%
 * Conclusion : "External beam irradiation combined with a transcatheter boost can result in long-term survival of patients with EHBD cancer. Both distant metastases and local recurrence develop in 25-30% of patients despite irradiation. Survival may be improved by using chemotherapy in combination with EBRT to impact disease relapse (local and distant). Because there may be a dose response with irradiation, survival may also be improved by increasing the dose of radiation delivered by transcatheter boost."

 * Minnesota PMID 9274796 -- Biliary tree malignancies: the University of Minnesota experience. (1997 Lee CK, J Surg Oncol. 1997 Aug;65(4):298-305.)
 * Retrospective. 15 patients, most perihilar treated with BT or EBRT
 * Median survival 8 months, 3 long term survivors

 * Adelaide Australia 1983-93 PMID 9153812 -- Intraluminal brachytherapy in the treatment of bile duct carcinomas. (1997 Leung JT, Australas Radiol. 1997 May;41(2):151-4.)
 * Retrospective. 15 patients transhepatic BT; 11 LDR, 4 HDR
 * Median survival: 12.5 months
 * Conclusion : "We conclude that the addition of intraluminal brachytherapy after biliary drainage prolongs survival and is a safe and effective treatment, but patients still have a high rate of local failure, and further studies will be needed to address this problem."

 * Sydney Australia 1989-94 PMID 8602818 -- Intraluminal brachytherapy in bile duct carcinomas. (1996 Leung J, Aust N Z J Surg. 1996 Feb;66(2):74-7.)
 * Retrospective. 16 patients transhepatic BT, 1 +EBRT
 * Median survival: 23 months
 * Conclusion : "We conclude that iridium-192 brachytherapy is a safe effective treatment for biliary tract carcinoma but a comparison between surgery and stenting would be of value. However, the cost of brachytherapy is not cheap and its value in this regard should be carefully analysed."

 * Hokkaido Japan 1983-91 PMID 8598352 -- The role of radiotherapy in the management of extrahepatic bile duct cancer: an analysis of 145 consecutive patients treated with intraluminal and/or external beam radiotherapy. (1996 Kamada T, Int J Radiat Oncol Biol Phys 1996; 34:767-74.)
 * Retrospective. 145 patients, 6 pre-op RT, 59 post-op RT, 54 radical RT, 23 palliative RT.
 * RT: ILRT mean dose 42.2 Gy (20-95 Gy @ 0.4 Gy/hr), EBRT mean dose 42.2 Gy (7.5-80 Gy). Total mean dose 67.8 Gy
 * Mean survival (5-year survival): Preop RT 8.4 mo (11%) vs. postop RT 21.5 mo (18%) vs. radical RT 12.4 mo (6%) vs. palliative RT 4.3 mo (0%)
 * Post-op RT MST: Stage I/II 32.0 months vs. Stage III/IV 18.6 months (p<0.05)
 * Post-op RT: mean survival EBRT 14.4 mo vs. ILRT 24.7 mo (p=0.05)
 * Adjuvant RT: EBRT vs. ILRT (p=NS)
 * No dose response, but trend in post-op RT group (MST 17 mo vs. 26 mo)
 * Total dose > 90 Gy showed higher incidence of hemorrhagic gastroduodenal ulceration
 * Conclusion : "High-dose radiotherapy, consisting of ILRT and EBRT, appears to be feasible in the management of EHBD cancer, and it offers a survival advantage for patients not suited for surgical resection [compared with historical controls] and patients with positive margins in the resected end of the hepatic side bile duct. Expandable metallic biliary endoprosthesis assists the internal bile flow and may lengthen survival after high dose radiotherapy."

 * Rome Italy
 * PMID 8638018 -- Role of intraluminal brachytherapy in extrahepatic bile duct and pancreatic cancers: is it just for palliation? (1996 Montemaggi P, Radiology. 1996 Jun;199(3):861-6.)
 * Retrospective. 31 patients (BD 18, pancreas 13) treated with BT (17 alone at 50 Gy, 14 at 30 Gy + EBRT 45 Gy + 5-FU)
 * Toxicity: no acute, 3 late GIB
 * Conclusion : "ILBT is an effective palliative treatment of unresectable extrahepatic bile duct and pancreatic cancers. Results suggest a possible "curative" role in specific clinical settings when properly integrated with other treatments."

 * PMID 7538501 -- Intraluminal brachytherapy in the treatment of pancreas and bile duct carcinoma. (1995 Montemaggi P, Int J Radiat Oncol Biol Phys. 1995 May 15;32(2):437-43.)
 * Retrospective. 12 patients, 5 billiary and 7 pancreatic CA with obstructive jaundice. 4 CCA patients stent + BT (50 Gy @ 1cm), 1 CCA patient stent + BT 48 Gy + EBRT 28 Gy. 4 pancreatic patients 5-FU
 * Cholangitis 25%, stent occlusion 25%. 1 gastric ulcer (BT+EBRT+5FU pancreatic pt)
 * Median OS 14 months
 * Conclusion : "The results in the EHBD patients suggest that the addition of ILBT after biliary drainage prolongs survival." [compared to previous series]

 * Emory PMID 7784581 -- Definitive radiation therapy for extrahepatic bile duct carcinoma. (1995 Tsujino K, Radiology. 1995 Jul;196(1):275-80.)
 * Retrospective. 27 patients, 7 pts EBRT (median 50.4 Gy) only and 20 pts EBRT (median 45 Gy) + BT (LDR 25 Gy until 1987, HDR 7.5 Gy thereafter). BT indicated for +SM and all palliative cases. 4 patients 5-FU
 * Median survival (2-year OS): 13 months (10%)
 * EBRT > 45Gy, men, BD confined tumors significantly better outcomes
 * Complications: cholangitis 61%, gastric obstruction 9%
 * Conclusion : "Patients with locally advanced EHBD carcinomas have a low survival rate. Certain factors, however, appear to have prognostic significance."

 * MSKCC PMID 8535808 -- Palliation of irresectable hilar cholangiocarcinoma with biliary drainage and radiotherapy. (1995 Kuvshinoff BW, Br J Surg 1995; 82:1522-5.)
 * 12 pts treated with internal drainage followed by ILRT
 * Median survival: 14.5 months, all patients survived >6 months
 * Conclusion : "Internal biliary drainage, in conjunction with radiotherapy, appears to be safe and effective palliation of irresectable or recurrent hilar cholangiocarcinoma. Patients can maintain a reasonable quality of life with an acceptable incidence of cholangitis, without the hindrance of external drainage devices."

 * Heidelberg Germany PMID 8040034 -- Combined external beam radiotherapy and intraluminal high dose rate brachytherapy on bile duct carcinomas. (1994 Fritz P, Int J Radiat Oncol Biol Phys. 1994 Jul 1;29(4):855-61.)
 * Retrospective. 30 patients (18 perihilar, 12 distal) treated with EBRT (30-45 Gy) and ILRT (20-45 Gy)
 * Median survival (5-year OS): 10 months (8%)
 * Palliative resection significantly better survival (12.1 months) than RT only (7.9 months)
 * Brachytherapy: Max 20 Gy boost best tolerated, decrease in cholangitis (8% vs. 23%)
 * Conclusion : "The present standard treatment schedule 40 Gy for the external beam and 20 Gy (fourfold 5 Gy) for the afterloading boost seems to be appropriate and well tolerated. After radiotherapy, a permanent supply of drainage should be made with a stent.

 * Turin Italy PMID 7520594 -- [Percutaneous treatment of hilar cholangiocarcinoma completed by high-dose rate brachytherapy. Experience in the first 5 cases] - [Article in Italian] (1994 Righi D, Radiol Med (Torino). 1994 Jul-Aug;88(1-2):79-85.
 * Case report. 5 patients.

 * Mayo Jacksonville PMID 1312319 -- Analysis of failure after curative irradiation of extrahepatic bile duct carcinoma. (1992 Buskirk SJ, Ann Surg 1992; 215:125-31.)
 * Retrospective. 34 pts treated with 5-FU, EBRT 45 Gy + 17 pts 5-15 Gy EBRT boost vs. 10 pts ILRT vs. 7 pts IORT
 * Median survival: 12 months

 * Lyon France 1980-88 PMID 1866463 -- Radiation therapy in extrahepatic bile duct carcinoma. (1991 Mahe M, Radiother Oncol. 1991 Jun;21(2):121-7.)
 * Retrospective. 51 patients, 4 radical resection, 10 positive margins, 12 palliative resection, 10 biopsy, 15 no surgery
 * RT curative (mean EBRT 45 Gy, ILRT 50-60 Gy) for radical/positive margin surgery, palliative (mean EBRT 35 Gy, ILRT 30 Gy)
 * Median survival (3-year OS): 12 months (15%)

 * Rotterdam PMID 2153649 -- The role of radiotherapy in the treatment of bile duct carcinoma. (1990 Veeze-Kuijpers B, Int J Radiat Oncol Biol Phys. 1990 Jan;18(1):63-7)
 * Retrospective. 42 patients (11 microscopic positive margins after surgery, 31 unresectable) given EBRT (40 Gy) + ILRT (25 Gy in 1 session)
 * Median survival 10 months, 3 patients > 30 months
 * Resection + RT better than RT alone (p=0.06)

 * Duke 1980-87 PMID 3344584 -- Internal radiation for bile duct cancer. (1988 Meyers WC, World J Surg. 1988 Feb;12(1):99-104.)
 * Retrospective. 27 patients (3 resected), treated with stent followed by BT and 22 also EBRT
 * Average survival: 13.5 months (2-58 months)
 * No surgical decompression 5.8 months vs. decompression 14.1 months
 * BT only 11 months vs. BT + EBRT 21 months
 * All patients had symptoms attributed to cholangitis, 21 severe
 * Conclusion : "Heterogeneity of patient material, pretreatment methods, and lack of controls preclude any statement concerning effectiveness of RT for bile duct cancer"

 * Utah 1980-1985 PMID 2843489 -- Definitive radiation therapy in bile duct carcinoma. (1988 Hayes JK, Int J Radiat Oncol Biol Phys. 1988 Sep;15(3):735-44.)
 * Retrospective. 24 patients, 75% proximal. 40% palliative/no RT and 60% definitive RT (EBRT, LIRT, or combination)
 * Median survival: palliative 2.0 months vs. definitive 12.8 months (p<0.005)
 * Complications were common, including bacterial sepsis (58%), cholangitis (38%), gastrointestinal bleeding (46%), intra or extrahepatic abscesses (33%), and recurrent biliary obstruction (25%)

 * Perth Australia PMID 2831118 -- Transpapillary iridium-192 wire in the treatment of malignant bile duct obstruction. (1988 Levitt MD, Gut. 1988 Feb;29(2):149-52.)
 * 24 patients with malignant bile obstruction (pancreas and CCA)
 * BT (median 60 Gy) via endoscopic catheter. One early death from CVA. Cholangitis 30%, stent blockage 40%
 * Median survival CCA 10 months, pancreas 8.3 months
 * Conclusion : "The ability of intraluminal irradiation to improve palliation or lengthen survival in patients with malignant bile duct obstruction remains uncertain."

 * Duarte CA PMID 3338957 -- Intracatheter hyperthermia and iridium-192 radiotherapy in the treatment of bile duct carcinoma. (1988 Wong JY, Int J Radiat Oncol Biol Phys. 1988 Feb;14(2):353-9.)
 * Case report. Locally advanced BD CA, EBRT 45 Gy + hyperthermia to 43-45C x 1 hr + BT 50 Gy over 72 hours
 * Pt asymptomatic 6 months after therapy. Duodenal ulcer.
 * Conclusion : "We believe the use of intracatheter hyperthermia in conjunction with external and/or intracatheter radiotherapy in selected patients with unresectable bile duct carcinomas warrants further study."

 * Wash U 1975-83 PMID 3104245 -- Carcinoma of the extrahepatic biliary system--results of primary and adjuvant radiotherapy. (1987 Fields JN, Int J Radiat Oncol Biol Phys. 1987 Mar;13(3):331-8.)
 * Retrospective. 20 patients with GB (3 pts) or billiary duct CA (17 pts). 9 pts EBRT (44 - 63.6 Gy) alone vs. 8 pts EBRT (21.6 - 50.4 Gy) + BT (19.5 - 25.7 Gy)
 * Median survival: EBRT alone 7 monts vs. EBRT + BT 15 months (p=0.06)
 * Conclusion : "Although numbers are small, these results appear to support the use of adjuvant radiotherapy in patients with microscopic residual GB cancer. Aggressive local and regional radiotherapy can add to the quality and length of survival in both patient groups, that is, those with resectable lesions with high likelihood of microscopic residual, and also those with unresectable or gross residual disease after surgery."

 * Munich Germany PMID 2448132 -- Endoprosthesis and local irradiation in the treatment of biliary malignancies. (1987 Classen M, Endoscopy. 1987 Nov;19 Suppl 1:25-30.)
 * "Non-surgical drainage procedures can be combined with endoscopic or transhepatic irradiation employing 192-iridium for intraluminal irradiation; further studies are, however, needed"

 * King's College Hospital PMID 2998683 -- Internal biliary drainage and local radiotherapy with iridium-192 wire in treatment of hilar cholangiocarcinoma. (1985 Karani J, Clin Radiol. 1985 Nov;36(6):603-6.)
 * Retrospective. 30 patients. BT 40-50 Gy
 * Mean survival 16.8 months (1-66 months). 21 survived >1 year
 * Conclusion : "We report a significant increase in mean survival to 16.8 months in patients treated with internal biliary drainage when combined with local irradiation to the tumour with iridium-192."

 * Lyon France PMID 6207904 -- Radiotherapy of high bile duct carcinoma using intra-catheter iridium 192 wire. (1984 Mornex F, Cancer. 1984 Nov 15;54(10):2069-73.)
 * Retrospective. 7 patients. BT 10-60 Gy at 1cm; 4 also EBRT 20-50 Gy
 * Mean survival 8.2 months (2-23 months). No systemic or local complications.
 * Conclusion : "This well-tolerated procedure permits symptomatic palliation without excessive side effects for the patient."

 * Mayo 1980-82 PMID 6436203 -- Analysis of failure following curative irradiation of gallbladder and extrahepatic bile duct carcinoma. (1984 Buskirk SJ, Int J Radiat Oncol Biol Phys. 1984 Nov;10(11):2013-23.)
 * Retrospective. 20 pts (16 BD, 4 GB) treated with curative RT (45-50 Gy to tumor and LNs). 10 pts 10-15 Gy boost +/- 5-FU, 8 pts ILRT 20-25 Gy, 2 pts IORT 15-20 Gy
 * Conclusion : "Further experience is necessary to determine whether this aggressive treatment will result in long-term disease-free survival in these patients."

 * Germany PMID 6697900 -- [Endoscopic intraductal radiotherapy of high bile-duct carcinoma] -    [Article in German] (1984 Phillip J, Deutsch Med Wochenschr. 1984 Mar 16;109(11):422-6.)
 * Case report, 3 patients. Endoscopic BT (60 Gy @ 0.5 cm, 0.85 Gy/min x 70 hours)
 * Conclusion : "The advantage over previously described methods (percutaneous transhepatic, surgical after installation of U-drainage) lies in a smaller complication rate and improved follow-up treatment as change of the endoprosthesis or repeat irradiation is not associated with renewed tissue trauma."
 * PMID 7053662 -- Diagnosis and treatment of primary extrahepatic bile duct tumors. (1982 Chitwood WR, Am J Surg. 1982 Jan;143(1):99-106.
 * Retrospective. 10 patients EBRT 30-50 Gy + BT 50 Gy.
 * 5 aliver 1-12 months post RT, 5 died after 3-4 months

 * PMID 7330164 -- Newer techniques in the diagnosis and treatment of proximal bile duct carcinoma--an analysis of 41 consecutive patients. (1981 Wheeler PG, Q J Med. 1981 Summer;50(199):247-58.)
 * 41 patients
 * Median survival: surgical drainage/bypass 9 months vs. no drainage 3 months
 * RT performed in 9 patients, improved survival compared with tube drainage alone
 * Conclusion : "The new percutaneous techniques offer a useful alternative to surgery for palliative drainage and radiotherapy."

 * King's College Hospital PMID 6114244 -- Treatment of high bile duct carcinoma by internal radiotherapy with iridium-192 wire. (1981 Fletcher MS, Lancet. 1981 Jul 25;2(8239):172-4.)

 * PMID 7208926 -- Irradiation of biliary carcinoma. (1981 Herskovic A, Radiology. 1981 Apr;139(1):219-22.)
 * Case report. 6 patients. 50 Gy BT
 * Tumor disappeared in 1, reduced in 5

 * Minnesota Papillary colloid adenocarcinoma of the extrahepatic bile ducts. (1935 Walters, W.; Olsen, P. F. Minn. Med. 18:460-462;

=Animal Model
 * Freiburg Germany PMID 8284744 -- [Radiation sensitivity of the normal bile duct during high dose rate afterloading irradiation with Iridium 192. Experimental studies in pigs] - [Article in German] (1993 Brambs HJ, Strahlenther Onkol. 1993 Dec;169(12):721-8.)
 * 16 pigs, ILRT 7.5 Gy and 15 Gy using an iridium-192 source. Significant lesions
 * Conclusion : "Single intraluminal high-dose-rate afterloading doses of 7.5 and 15 Gy cause significant lesions and complications at the bile ducts. As the intact bile duct is the Achilles heel of intraductal therapy, considerably lower single doses are recommended for a fractioned treatment."


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Talk:Evolution of Operating Systems Designs/What is an Operating System?

An operating system: programming code specifically used as a base to provide basic functionality to electronic devices.

''Useless since you'll have to define "basic functionality" then and some idiot will claim that the kernel is the only operating system even though kernels have nothing to do with operating systems. And completely false since VM microcode will be the "operating system" of some embedded devices. Better luck next time.''

''And what exactly is your problem with the proposed definition anyways? The definition works best on well-designed operating systems like Smalltalk. The entirety of the Smalltalk system is the operating system and if anyone claimed that only a tiny subset of it (the part needed to get "basic functionality") were the OS, they would be dismissed.''

''Bringing the word "programming" into it was a good idea but you missed the mark completely. The operating system is the entirety of the (coherent) system that is programmatic in nature and so serves as a base for further programming. It has nothing to do with "functionality" nor with "basic" vs "advanced".''

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November 11, 2005

“Define "basic functionality””. Since the hardware software needed to make a device useful varies from electronic device to electronic device; I would have to define basic functionality as the bare minimum needed to allow whatever hardware one device contains to function and be useful. The whole point of basic functionality would be that the Operating System would need to contain all that it is need for it to serve purpose it is designed for. Your point about the kernel or a fraction of any operating system is pointless as the most basic function of the operating system is to be useful for the propose it was designed for; the kernel or a fraction of any operating system by themselves will not allow electronic devices to function at a level that would be considered useful.

LOL

I do understand that a computer with nothing more than an operating system installed is to some degree useless. However, a computer in such a state that is up and running would be ready for additional software to be installed, thus allowing the computer and the operating system to go from a state of basic functionality to full or advanced functionality; depending on the total propose of the computer.

''My point about kernels is this. First of all they are kernels and not operating systems so calling them operating systems violates standard use of language. If a definition allows kernels to be considered operating systems then the definition is simply wrong.''

''Second, you can strip an operating system even lower than the kernel by stripping the kernel of functionality and still call it an operating system. But you can't do this logically, you can only do it physically. If you have an operating system on device A which is simply the kernel of the operating system on device B then both are operating systems. But if you talk about a fraction of the operating system on device B then that is NOT the operating system. The operating system is the entirety of the coherent system. And since Unix software *routinely* makes use of shell scripts, then all of these standard utilities that exist in a Unix system are part of Unix.''

''Note the point about the X Window system is thin. X Window is, I think, used programmatically by window managers. But of course, window managers are never used programmatically by end users. And in either case, none of them are programmed in a way remotely similar to everything else in Unix.''

.........

''And what exactly is your problem with the proposed definition anyways?”

I felt it was incomplete and lacking something. Wasn’t sure what it was so I added my 2 cents. Seems like the definition has changed… I like the new one as it makes it easier for someone that is not a programmer to understand. Furthermore, the whole point of defining something is to help people understand what is being defined. The previous definition really didn’t seem to state what an operating system is in plain English. For the most part it seemed to be a politician’s/lawyer’s answer to a question that he/she was unsure of and was explained in the most complex and broadest way possible in an attempt to make those that didn’t understand turn away and not say anything (As opposed to saying something and sounding stupid.) while still saying enough to allow someone that understands to agree that it is correct.

One more point, it is my understanding that the whole point to propose a definition is to generate feedback; unless this was suppose to be one of those rhetorical proposals?

''Ideally, and always with me, the whole point of a definition is to get it right. Useful feedback generally takes the form of "the definition applies to X which we all agree is not one of those things we want included" or "the definition doesn't apply to Y even though we all agree it's one of those things we want included". In your case, it would have been "using the definition, I can't even tell whether or not X and Y are included or excluded". Note that this is the form my feedback to your proposal took.''

''Now granted, I knew the definition I gave was deficient but the inspiration that fixed it was a stroke of dumb luck. Programmatic vs interactive use has been a sometimes recurring theme in my mind for years. I think it would have been more reasonable to attack the coherence criterion and demand that some kind of criterion be drawn up to draw the boundary between what's part of the OS and what isn't.''

---

=
=======

You can call it dumb luck; I call it inspiring people to be their best. (If you can’t dazzle them with brilliance, baffle them with BS, right?)

lol... I will admit I’m not always right, but when I give my 2 cents it tends to inspire people. I wasn't trying to redefine it; I was merely stating what I believed an OS to be. As stated on the main page "the software that comes on an operating system install CD” is not even close to what an OS is. I’m not educated, but I know enough to know that what is included on of those disks normally exceeds what an OS truly is. In the case of WinXP, screen savers, spider solitary, so on and so forth are not part of the OS. Basic functionality was a way to eliminate such items from what I believed the to be OS. Basically I think we were trying to answer or define two aspects of what an OS is.

I was thinking about the commodity aspect, what is bought and sold. Well basicly. Apparently you are defining what is deeper within the OS as in what an operating system does. So as far as my comments being X or Y, the answer is 42. ;-) This brings your point about the kernel or a fraction of any operating system into perspective. While there are components of an operating system that in many ways mimic the behavior and fit general concept OS, the components are not operating systems because they require the system as a whole to do thier function. I don’t know if I explained it correctly but I think I understand what you are trying to define. To be honest it sounds like you are defining what an OS does and/or what can be considered an OS based on what it dose and how it does it.

So one might confuse a kernel with an OS because the kernel is A set of principles and concepts and all of the components which obey these principles designed to provide system stability.(to make a long story short) However, because the kernel is dependant on all the other processes of the OS as a whole to be able to function, it can not be defined as an OS. There is a great deal of difference in what we were trying to define.

So you are defining what an OS can and can not be based on what it does, at the same time you are defining various components of an OS that have the same general concept of the OS, that can not be defined as an OS because they require the OS as a whole to function, and without the OS as a whole they have no function.

''I forgive a lot from people who are genuinely trying to help. As opposed to people who are simply trying my patience *cough* AlbertCahalan *cough* *cough*. If you see any other weaknesses, please bring them up and be as brutally forthright as you can. Just so long as you put in a genuine effort to understand.''

Next up is defining systems design, partly so I can exclude certain people who are trying my patience, but mostly because most people (and even more so for programmers) really don't know what it is. 24.200.176.92 02:55, 12 November 2005 (UTC)

=
= am I any closer to the subject this time?

''Heh, missed this first time through. Okay, your understanding of what OSes are seems very close but not quite on target. For certain kinds of users, very humdrum engineering types, an OS is something much reduced from what it is to most people. For them, an OS may be a kernel, a shell, a couple of utilities, a filesystem, various drivers, and that's pretty much it. And that would be the OS they use to develop on, as opposed to the OS they are targeting. The OS they are targeting could be even more stripped of function. It could have no utilities, fewer drivers, a rudimentary shell at best, a rudimentary filesystem, maybe even a stripped down kernel. This is the world of embedded systems.'' --

I assure you I’m not here solely to annoy you. I’m not sure how much more I can help you; however I do have a genuine interest in this subject. I have decided to do a little more research on the subject before add anything else so it might be a week or two before I get back with questions/comments.

To flesh this book out a bit, I rewrote information from Tanenbaum's Operating Systems design and Implementation sec ed. (1997) for a more comprehensive historical view of what an operating system is and has been.--Graeme E. Smith (talk) 15:49, 23 April 2009 (UTC)

Repaired what I am pretty sure was annonymous vandalism where Babbages name was replaced with Ajay Babbage is a historical figure, and Ajay, is probably someones first name.--Graeme E. Smith (talk) 13:50, 22 July 2009 (UTC)

-

People who have had no technical introduction to Operating System design seem to fall victim to the Microsoft Marketing Mythos.

They seem to obtain some peculiar attitude towards the word "kernel". I suggest you all grab 4 or 5 good academic texts on operating system design and read the definition each one gives for what an operating system is.

Across the board, You'll find some very similar characteristics. And you'll find that in nearly every case, the word kernel and Operating system will have a 98% concordance. Not identical, but always nearly identical. 24.91.86.136 (discuss) 17:55, 26 January 2013 (UTC)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
CAT-Tools/DéjàVu X/RTF format (Trados)

You need at least the Demo version of Trados. Here is the solution for Word and RTF files and files processed with S-Tagger (rtf files with a lot of tags).

If you get unsegmented files from your customer (segmented files contain every sentence twice - the source sentence is marked hidden and between the source and the target sentences you have things like <}0{> with varying numbers):

Open Trados WB with the TM from your customer (if you have a proper Trados version) or create a new empty TM in your language pair (if you have the Demo), go Tools, Translate, select the option segment unknown sentences, select the files you need to translate and click on Translate. The result is untranslated, segmented, uncleaned Trados files.

For each file you have now 2 files, one with the original extension (e.g. rtf) and one with the extension BAK, which is a backup of your original.

Close Trados WB.

Create a project in DVX. Select the files you want to import – the ones with the original extension. In the import window of the Wizard highlight all of them and click on the button Properties. Click in the field Filter that shows Microsoft Word or Rich text format (depending on your files). Select Trados Workbench. Now import your files and translate them.

Be careful to check for code errors (CTRL+Shift+F8) before exporting.

After the export, you have uncleaned, translated Trados files.

If you need to clean them, open Trados WB, Tools, Cleanup, select do not update TM and select your translated files, click Cleanup. No you have cleaned files (files with the extension you first had) and uncleaned files with the extension BAK.

If your customer has sent you a TM and you do not have a full Trados version, you need to get the TM as a Trados.txt or TMX export. You cannot do this conversion in the Trados Demo. If you want to import a Trados.txt file into a DVX Database you must select Trados Workbench as import format, even if it is a txt file. If you forget this, you will get a lot of tags you do not want to have in your TM.

If you get Tag Editor files (TTX) and after importing them in to DVX you do not see any segments- the files where not segmented in Trados WB. You need to segment them just as described for the Word files.

After importing the TTX file, you need to use the Rows Selector to switch from All Rows to Unpainted Rows. Then right-click on the translation grid and select Clear All Translations (not to worry: this actually means Clear All Translations *In This View*). Now switch back to All Rows using the Rows Selector. Now that all rows with no matches are empty, Auto-Assemble will work on CTRL/ALT+down (if enabled). On non-empty unpainted rows you would have to press CTRL+A to assemble those segments.

title: CAT-Tools/DéjàVu X/RTF format (Trados)


text: User talk:Psychonaut

title: User talk:Psychonaut


text:
User talk:Oyvind~enwikibooks

images
Thanks for your help, but I don't think we need massive tagging of images with no license. It's a job for a bot.

Some of these images are old and people often weren't aware that they should tag files with copyright tags (in fact, these tags were not complete). You can write to images authors to fix them. F.e. Jer54 is an active user and he tagged some of his images when I reminded him. You can use image copyright at user pages. --Derbeth talk 10:17, 18 November 2005 (UTC)

I realize you mean well, but please consider using the discussion or talk pages before making dramatic cuts to our wikibook. I know you are trying to help us improve, but these edits may rub some of us the wrong way, and I want folks to welcome outside assistance. A little courtesy is all I ask. Thanks. --Mattbarton.exe 01:10, 19 November 2005 (UTC)

Well, honestly I don't mind your removing the possible copyright violations. I didn't put those images there and can't account for them. We're just wondering about the title graphic, which we custom made for the project. Not sure what the problem is with it. --Mattbarton.exe 02:58, 20 November 2005 (UTC)

Your account will be renamed
Hello,

The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.

Unfortunately, your account clashes with another account also called Oyvind. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Oyvind~enwikibooks that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:33, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 05:20, 19 April 2015 (UTC)

title: User talk:Oyvind~enwikibooks


text:
User:Max~enwikibooks

Just finishing up an undergrad in Entrepreneurship, I am here because wikis are our future. I contribute to The Strategy Tree, an entrepreneur-focused wiki that is just starting up. My interests are creativity, humans, learning, and spirituality, and the nexus of those four.

An example of our future: Today I set up a wiki on PBWiki for a class where my team is working on writing a business plan. When we had our meeting tonight, we edited the plan as we talked about it. I am planning how to spread the use of wikis for team projects throughout my university.

--Max 11:09, 11 November 2005 (UTC)

title: User:Max~enwikibooks


text:
User talk:Max~enwikibooks

Any projects I can help with? Please comment here.

Your account will be renamed
Hello,

The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.

Unfortunately, your account clashes with another account also called Max. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Max~enwikibooks that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:26, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 05:14, 19 April 2015 (UTC)

title: User talk:Max~enwikibooks


text:
Radiation Oncology/Bile duct/Periampullary

Imaging

 * MRI: Korea, 2002 - PMID 12432106 — "Differential diagnosis of periampullary carcinomas at MR imaging." Kim JH et al. Radiographics. 2002 Nov-Dec;22(6):1335-52.

Treatment

 * MGH Pattern of Failure Study PMID 8093983 -- Patterns of Failure after pancreaticoduodenectomy for ampullary carcinoma. (Willet CG, Surg Gyne Obstet. 1993 Jan; 176 (1):33-8.)
 * Retrospective. 41 pts with ampullary carcinoma.  69% local control, 55% OS at 5 yrs.
 * Low risk features included limited to ampulla/duodenum, well differentiated, node neg, clear margins. Low risk w/ 100% local control and 80% OS at 5yrs.
 * High risk features included invasion of pancreas,poorly differentiated,+nodes/margins. 50% local control and 38% OS at 5yrs.  Xrt appeared to benefit local control in this cohort.  Distant mets (liver, peritoneum, pleura) were dominant mode of failure in hi risk group.

 * EORTC  PMID 10615932 -- Adjuvant radiotherapy and 5-fluorouracil after curative resection of cancer of the pancreas and periampullary region: phase III trial of the EORTC gastrointestinal tract cancer cooperative group. (Klinkenbijl JH, Annals of Surgery. 1999 Dec; 230(6):776-82.)
 * Randomized prospective. Included both pancreatic head and peri-ampullary tumors.  T1-T3, N0-N1a peri-ampullary allowed. 218 pts total.  45% had peri-ampullary.  Randomized to 5FU/xrt vs observation. On subgroup analysis, 2yr OS for peri-ampullary CA was 63% (obs) vs 67% (chemoxrt) p=0.737.  No reduction in locoregional recurrence rate was seen in this group.
 * Stanford 1995-99 PMID 11146780 -- Adjuvant chemoradiotherapy for "unfavorable" carcinoma of the ampulla of Vater: preliminary report. (2001 Mehta VK, Arch Surg. 2001 Jan;136(1):65-9.)
 * Prospective. 12 patients with "unfavorable" features (+LN, positive margins, poorly differentiated, >2 cm, neurovascular invasion). After surgery, RT 45 Gy + continuous infusion 5-FU. **2-yr OS 89%, MS 34 months, 8/12 disease-free at 2 years.
 * Conclusion : "Adjuvant chemoradiotherapy for carcinoma of the ampulla of Vater is well tolerated and might improve control of this disease in patients with unfavorable features."


text: Formal Logic/Merged Versions/Sentential Logic


text:
Talk:Embedded Systems/PIC Microcontroller

Contributors:
 * DavidCary 17:41, 24 Feb 2005 (UTC)
 * Stingraze 04:17, 23 Jan 2005 (UTC)

power supply
What is the point of the "Power Supply" section?
 * I wouldn't build the supply described there if I were buying a PIC programmer, since it would already come with the appropriate power supply built in.
 * I wouldn't build the supply described there if I were building my own PIC programmer. Each one of the over a dozen complete "build your own PIC programmer" projects has complete instructions for building its own power supply. Most of those power supplies are very different and incompatible with the one currently described in the "power supply" section.

--DavidCary 20:59, 17 February 2007 (UTC)

 * Deleted. --DavidCary (talk) 15:26, 26 August 2009 (UTC)

UV-erasable and OTP PICmicros
As far as I can tell, *all* of the UV-erasable and OTP PICmicros (PIC12C, PIC16C, PIC17C, PIC18C) are no longer recommended for new designs. I fail to see the point of long discussions of the details of some obsolete chip before getting to the "good stuff" describing some chip that might actually be useful.

I'm going to strikethrough ( strikethrough ) all mention of such chips for now. Should I simply delete all all mentions of such chips, or is there something about these chips important enough to mention in the "history" section?

--DavidCary (talk) 15:26, 26 August 2009 (UTC)

I've unstriked some of the sections I considered useful. I agree that instead of teaching people with almost obsolete chips we should show them the brand-new chips beeing produced. Remember: the 16F84 remained in the hobbyist community for a while because no one wanted to start with something new to the area! Let's change that!

--User:ivaneduardo747


text:
Embedded Systems/Common Protocols

This is a list of common protocols used in embedded systems. Eventually, this list will become hyperlinks to sources of information on each. Many of them are byte-stream protocols that can be transmitted by a variety of serial protocols on a variety of hardware.

 * I2C
 * RS-485 is an extremely common hardware arrangement used by many embedded protocols:
 * CAN on top of RS485
 * DeviceNet on top of CAN. DeviceNet
 * NMEA 2000 on top of DeviceNet. NMEA 2000
 * DMX on top of RS485. DMX512
 * Modbus on top of RS485
 * see Serial Programming/RS-485, Robotics/Computer Control/The Interface/Networks, Embedded Control Systems Design/Field busses, Embedded Systems/Serial and Parallel IO
 * MIDI. official MIDI interface schematics (1); beautiful MIDI IN schematic (2).
 * BlueTooth
 * InfraRed
 * ZigBee
 * SPI
 * RS-232
 * USB
 * IP Over Serial Connections
 * MINES (Microcontroller Interpreter for Networked Embedded Systems) was designed for very small embedded systems (see Gallery of MINES Devices).
 * the Tiny Embedded Network
 * IEEE Standard for Sensor Transducer Interface
 * the three byte Mini SSC protocol (and another Mini SSC protocol example)
 * JTAG
 * NTSC / PAL television video output: TV Typewriter, Generating TV signal by PSoC, Generating TV signal with the PICs, PIC Breakout, ... Parallax Propeller has a video generator ...
 * The low-latency Myrinet protocol is used in over 100 of the TOP500 supercomputers, as of June 2005.
 * The low-latency InfiniBand protocol is used in over 100 of the TOP500 supercomputers, as of November 2010.
 * The various Audio over Ethernet (AoE) protocols are generally designed to be relatively low latency.
 * The LIN-Bus (Local Interconnect Network), a low-cost vehicle communication network
 * Modbus (Modbus) protocol works over a variety of hardware interfaces, including
 * Modbus RTU over RS-485
 * Modbus ASCII over 7-bit asynchronous serial lines
 * Modbus TCP over Ethernet
 * Firmata is a generic protocol that allows people to completely control the Arduino from software on a host computer. Arduino reference for Firmata; Firmata wiki.
 * rosserial "rosserial ... is a general protocol for sending ROS messages over serial links." Code is available for Arduino and a variety of other platforms. (It was designed for ROS, the Robot Operating System).
 * S.N.A.P - Scaleable Node Address Protocol is media-independent, building on an underlying byte-oriented communication layer.
 * Yet Another Scalable Protocol (YASP)
 * Labor-Octet-Protocol (LOP) is a simple protocol originally implemented on AVR microcontrollers; it builds on an underlying byte-oriented communication layer and provides support for both message-oriented (all-or-nothing) and stream-oriented communication.
 * Inter-Chip Serial Communications (ICSC) is a simple, high-reliability media-independent protocol originally implemented on Arduino.
 * Perhaps the simplest-to-parse variable-size packet container format is the netstring format.netstring
 * JSON (perhaps encapsulated in packets of one of the above formats) seems to be gaining popularity as a way to transmit complex data structures, in a way that is easy for humans to read and debug. JSON

title: Embedded Systems/Common Protocols


text:
Template:User admin

 This template will add you to Category:Wikibooks administrators.

title: Template:User admin


text:
Talk:Mac OS X Tiger/Appendix D

DO NOT USE THIS PAGE TO PLUG SOFTWARE!

the first thing i asked myself when i switched on a mac was "ok, now where's the start menu?" another thing i asked myself was "one does not right-click in macs?"

title: Talk:Mac OS X Tiger/Appendix D


text:
Talk:Embedded Systems/Embedded Systems Introduction

Embedded System: Theory Design and Implementation
I've merged that book into this current book. Here, i've saved some of the important history notes from the previous book. --Whiteknight T C E 16:20, 11 November 2005 (UTC)

Contributors:
 * --Siddord 07:10, 30 August 2005 (UTC)

HOC
Please add a note in the History of Changes page as and when you add or edit anything in the book. This will be very helpful to maintain a systematic record of the development process of this book. A HOC page will be maintained for each page section of the book. HOCs will be archived and removed once the book is stable and almost complete. Thank you. --Panic 03:43, 14 August 2005 (UTC) - added wikipedia template

--Panic 03:29, 14 August 2005 (UTC) - added foreword template will do anotehr for authors

12/08/2005 - sid - added power for pic programmer page

12/08/2005 - sid - combined the HOCs

10/08/2005 - sid - added Introduction subsection for PIC microcontrollers

09/08/2005 - sid - added Introduction chapter


text:
User:Tdvorak/Red Journal

Red Journal Home

Glioma

 * 15.Jul.06 - Toxicity is acceptable at the current doses of erlotinib plus RT
 * 15.Nov.05 - Cognitive function was stable after RT in supratentorial low-grade gliomas evaluated prospectively during 3 years of follow-up.

Trigeminal Neuralgia

 * 15.Jul.06 - The use of plugs to protect the brainstem during GKR treatment for TN increases the dose of irradiation delivered to the intracisternal trigeminal nerve root and is associated with an important increase in the incidence of trigeminal nerve dysfunction.

Orbit

 * 15.Jul.06 - Brachytherapy using 106Ru plaques is a highly efficient therapy with excellent local tumor control and an acceptable incidence of side effects.
 * 15.Nov.05 - Fractionated proton radiotherapy is superior to 3D conformal photon radiation in the treatment of orbital rhabdomyosarcoma.

H&N

 * 15.Jul.06 - Paraganglioma. External-beam RT and SRS are safe and effective for enlarging and/or symptomatic paragangliomas.
 * 15.Jul.06 - Conventional head-and-neck radiotherapy is associated with substantial functional deficits and diminished HR-QOL.
 * 15.Jul.06 - Patients with early hypopharyngeal cancer tended to have a good prognosis after radical RT. However, second malignancies had an adverse effect on the overall outcomes of patients with early hypopharyngeal cancer.
 * 15.Jul.06 - PI/II. Concurrent docetaxel/concomitant boost radiation and surgery after induction chemotherapy in poor prognosis patients yields good local regional control and survival.
 * 15.Jul.06 - Prevertebral muscle involvement is an independent prognostic factor for NPC recurrence.
 * 15.Jul.06 - Use of FDG-PET was found to influence the salvage treatment decision making for locally persistent NPC by identifying patients who were not likely to benefit from additional treatment and by improving accuracy of GTV definition in salvage treatment planning.
 * 15.Nov.05 - PIII. Amifostine administration during head-and-neck RT reduces the severity and duration of xerostomia 2 years after treatment and does not seem to compromise locoregional control rates, progression-free survival, or overall survival.
 * 15.Nov.05 - Retrospective. For patients who have no evidence of residual lymphadenopathy and a negative FDG PET scan 12 weeks after definitive radiation, neck dissection can be safely withheld. Even in cases in which small residual lymphadenopathy was observed, regional recurrences have not occurred when the post-RT PET scan was negative and neck dissection was withheld. For patients with large residual lymphadenopathy (greater than 2.0–3.0 cm in size) but a negative post-RT FDG PET, further studies with longer follow-up are necessary to determine the appropriateness of withholding neck dissection.
 * 15.Nov.05 - Regarding target volumes, acceptable plans can be generated with either WF-IMRT or HB-IMRT. WF-IMRT has an advantage if uncertainty at the match line is a concern, whereas HB-IMRT, particularly in cases not involving the base of tongue, can achieve much lower doses to the larynx.
 * 15.Nov.05 - Stimulated flow measurements using Lashley cups, with a complication defined as flow ≤25% of the preradiotherapy output, correlated best with the mean parotid gland dose. When reduction of the mean dose to the parotid gland is intended, the stimulated flow measurement is the best method for evaluating parotid gland function.
 * 15.Nov.05 - Radiation appears to cause carotid artery stenosis. There may be a dose threshold for carotid wall changes, which has relevance for radiotherapy in several tumor sites.

NSCLC

 * 15.Jul.06 - This retrospective analysis identified KPS and weight loss as the most important prognostic factors of outcome in patients with early-stage NSCLC treated with hyperfractionation (1.2 Gy BID to 69.6 Gy) radiation therapy.
 * 15.Jul.06 - PI. RT dose escalation of weekly carboplatin/paclitaxel. The MTD was 74 Gy.
 * 15.Jul.06 - Patterns of failure after resection of non–small-cell lung cancer. Most common was bronchial stump/staple line
 * 15.Jul.06 - Proton treatment appears to reduce dose to normal tissues significantly, even with dose escalation (up to 87.5 Gy), compared with standard-dose photon therapy, either 3D-CRT or IMRT.
 * 15.Jul.06 - Dose escalation 69-103 Gy. With long-term follow-up for toxicity, we have demonstrated that much higher doses of radiation than are traditionally administered can be safely delivered to a majority of patients with NSCLC.
 * 15.Nov.05 - PI. Stereotactis BS. MTD T1 >60 Gy, MTD T2 72 Gy for tumors >5cm
 * 15.Nov.05 - PET/CT radiation treatment planning is a useful tool resulting in modification of GTV in 52% and improvement of interobserver variability up to 84%.
 * 15.Nov.05 - With the advent of in-room soft-tissue imaging techniques such as megavoltage CT imaging with a helical tomotherapy unit, daily documentation of the status of a grossly visible targeted tumor becomes possible. The current study demonstrated that tumor regression can be documented for patients with non–small-cell lung cancer treated with helical tomotherapy.
 * 15.Nov.05 - The response by conventional response criteria (CR/PR) correlated strongly with improved overall survival and progression-free survival and an increasing percentage of decrease in tumor size resulted in a reduction in the risk of death.
 * 15.Nov.05 - PII. Induction chemotherapy with gemcitabine and vinorelbine followed by concurrent chemoradiotherapy 63 Gy with etoposide and cisplatin showed very promising survival in patients with Stage III NSCLC, especially in those without supraclavicular nodal involvement

Mesothelioma

 * 15.Nov.05 - Retrospective. Pleurectomy/decortication with adjuvant radiotherapy is not an effective treatment option for patients with MPM. Our results imply that residual disease cannot be eradicated with external RT with or without brachytherapy and that a more extensive surgery followed by external RT might be required to improve local control and overall survival.

Breast

 * 15.Jul.06 - Sequential high doses of epirubicin, preceded by dexrazoxane, and paclitaxel did not adversely affect the tolerability of locoregional RT in breast cancer patients.
 * 15.Jul.06 - During external breast irradiation, many patients will have significant (>20%) volume reduction in the lumpectomy cavity.
 * 15.Jul.06 - PIII. Hyperfractionated BID RT does not reduce the risk of locoregional recurrence in patients with locally advanced breast cancer treated with chemotherapy and mastectomy compared to QD
 * 15.Jul.06 - Even in this highly selected cohort, a substantial risk of local recurrence occurred after BCS alone with margins of 1.0 cm or more. These results suggest that with the possible exception of elderly women with comorbid conditions, radiation therapy after BCS remains standard treatment.
 * 15.Nov.05 - This ex-ante cost evaluation of internal mammary-medial supraclavicular LN chain RT showed that the upfront costs of locoregional RT are easily compensated for by avoiding the costs of treating locoregional and distant relapse at a later stage.
 * 15.Nov.05 - Retrospective. Stage I/II treated with BCT +/- systemic chemo. LVI was the strongest independent prognostic factor for OS, DFS, and local recurrence, irrespective of nodal status and systemic adjuvant treatment. Although LVI may not be a contraindication for BCT, as has been proposed by certain groups, it is necessary to define its role in prospective studies in determining local and systemic treatment.

Esophagus

 * 15.Jul.06 - PI/II. Our findings failed to demonstrate an improvement in pCR or survival with PFT-R (5FU/paclitaxel/RT) vs. PF-R (5FU/cisplatin) in locally advanced esophageal CA.
 * 15.Nov.05 - Pathologic response of an initially highly metabolic tumor after neoadjuvant chemoradiotherapy could be correlated with the metabolic response, and FDG-PET can provide additional information on tumor response to chemoradiotherapy.

Liver

 * 15.Nov.05 - Lymph node metastasis from HCC is sensitive to EBRT. EBRT with 25 fractions of 2 Gy is an effective palliative treatment for patients with LN metastases from HCC presenting with good performance status and may prolong overall survival.

Pancreas

 * 15.Nov.05 - IORT is well tolerated and does not increase the morbidity or mortality of potentially curative surgical resection for pancreatic or periampullary adenocarcinoma.

Rectum

 * 15.Jul.06 - We propose to include the primary tumor, the mesorectal subsite, and the posterior pelvic subsite in the CTV in all patients. Moreover, the lateral lymph nodes are at high risk for microscopic involvement and should also be added in the CTV.

Prostate

 * 15.Jul.06 - With reliable dose data available in the operating room, our results question the need for routine postimplant dose studies.
 * 15.Jul.06 - Intrarectal amifostine. This trial suggests greater rectal radioprotection from acute effects with 2 g vs. 1 g amifostine suspension.
 * 15.Jul.06 - For prostate cancer with ECE, the median linear distance of ECE was 2.4 mm and occurred primarily posterolaterally (along neurovascular bundle). Although only 5% of patients demonstrate ECE >4 to 5 mm beyond the capsule, this risk may exceed 20% in patients with PSA ≥10 ng/ml and biopsy Gleason score ≥7.
 * 15.Jul.06 - Anemia is a common side effect of NAST and is usually mild. Hb levels, however, do not predict biochemical control or survival.
 * 15.Jul.06 - Neoadjuvant HT and hypofractionation (52.5 Gy in 20 fxs). Not good.
 * 15.Jul.06 - New risk groups for >70Gy
 * 15.Jul.06 - Biochemical failure now defined as (1) a rise by 2 ng/mL or more above the nadir PSA be considered the standard definition for biochemical failure after EBRT with or without HT; (2) the date of failure be determined “at call” (not backdated)
 * 15.Nov.05 - Cone Beam CT scans are suitable for automatic online and offline position verification of the prostate, as long as the amount of nonstationary gas is limited.
 * 15.Nov.05 - A volume effect was found for acute GI toxicity for relative, as well as absolute, volumes. With regard to acute GU toxicity, an area effect was found, but only for absolute dose–surface histogram parameters. Neoadjuvant HT appeared to be an independent prognostic factor for acute toxicity, resulting in less acute GI toxicity, but more acute GU toxicity. The presence of pretreatment GU symptoms was the most important prognostic factor for GU symptoms during RT.
 * 15.Nov.05 - Retrospective. Hypofractionated carbon ion radiotherapy with the established dose fractionation regimen yielded satisfactory bNED without local recurrence and with minimal morbidity.

Cervix

 * 15.Nov.05 - No difference was found in severe late toxicity, overall survival, or disease-free survival between the LDR and PDR groups.
 * 15.Nov.05 - Patterns of BT care 1996-1999
 * 15.Nov.05 - Overexpression of iNOS or COX-2 or both was associated with decreased survival and a greater propensity to metastasize in cervical cancer patients treated with radiotherapy.

Endometrium

 * 15.Jul.06 - Extended-field IMRT is safe and effective with a low incidence of acute toxicity.
 * 15.Nov.05 - Medically inoperable Stage I endometrial carcinoma may be safely and effectively treated with HDRB as the primary therapy. In selected Stage I patients (MRI Dx, BT>30Gy, our results are equivalent to that of surgery.

Ovary

 * 15.Nov.05 - In carefully selected patients with locally recurrent ovarian cancer, combined IORT and tumor reductive surgery is reasonably tolerated and may contribute to achieving local control and disease palliation.

Pelvis

 * 15.Nov.05 - CT based LNs marked
 * 15.Nov.05 - Conformal four-field planning with individually optimized PTVs (D) resulted in only moderate tissue complication probabilities in both kidneys with the advantage of providing significantly greater inclusion of potentially involved para-aortic LNs in comparison to accepted standard procedures (A and C).

Hodgkin's Lymphoma

 * 15.Nov.05 - EORTC 20884. In advanced-stage HL patients in complete remission after six to eight cycles of MOPP-ABV, the outcome was not influenced by violation of the radiotherapy protocol (24 Gy to all initially involved nodal areas, 16–24 Gy to all initially involved extranodal sites.)

NHL

 * 15.Jul.06 - Radiation therapy should be considered early in the course of relapsing, refractory, or localized MCL.

Leukemia

 * 15.Nov.05 - ALL. Patients who present with hematologic disease only at the time of HSCT have a low risk of CNS recurrence after TBI regardless of the use of a cranial boost, suggesting that a cranial boost may not be necessary in these patients.

Peds

 * 15.Jul.06 - RS is safe and effective in pediatric cerebral AVM with high obliteration rates.
 * 15.Jul.06 - A reduced dose of 36-Gy EBRT after delayed GTR may maximize local control while minimizing long-term sequelae for very young children with RMS, but unresectable tumors (e.g., parameningeal) require higher doses.
 * 15.Nov.05 - Radiation-induced osteosarcomas in the pediatric population

H&N

 * 15.Nov.05 - The potential advantage of radioactive 9C-ion beam in cancer therapy has been revealed at low dose rate in comparison with a therapeutic 12C beam. This observation, however, remains to be investigated at therapeutic dose rates in the future.

Lung

 * 15.Nov.05 - A combination of radiotherapy and OGX-011 (anti-clusterin) improved control of tumor growth and vascular regression in the H460 lung cancer model.

Rectum

 * 15.Nov.05 - Caffeic acid phenethyl ester (CAPE) sensitizes CT26 colorectal adenocarcinoma to IR, which may be via depleting GSH and inhibiting NF-κB activity, without toxicity to bone marrow, liver, and kidney. Pretreatment with CAPE neither affected body weights nor produced hepatic, renal, or hematopoietic toxicity.

Prostate

 * 15.Nov.05 - These data indicate that phosphatidylinositol-3-kinase inhibition increases sensitivity of prostate cancer cell lines to ionizing radiation through inactivation of protein kinase B (PKB). Therefore, PTEN mutations, which lead to PKB activation, may play an important role in the resistance of prostate cancer to radiation therapy. Targeted therapy against PKB could be beneficial in the management of prostate cancer patients.
 * 15.Nov.05 - It may be advantageous to give adjuvant EBRT shortly (∼1 to 2 days) after commencement of clinical LDR brachytherapy, when the pO2 in the spatial regions between seeds should be elevated. If chemotherapy is given adjuvantly, it may best be administered just a little later (∼3 or 4 days) after the start of LDR brachytherapy, when perfusion should be elevated.

Seminoma

 * 15.Nov.05 - Most partial body irradiated patients (testicular seminoma) showed a significant temporal decline of translocation frequencies during a 36-month period. Thus, reciprocal translocations after partial body irradiation cannot be regarded as stable over time. The temporal decline of aberration frequencies has to be taken into account for retrospective dose estimations.

Prostate

 * 15.Nov.05 - Relative to skeletal anatomy, nodes covered a diffuse volume from the mid lumbar spine to the superior pubic ramus and along the sacrum and pelvic side walls. In contrast, the nodal metastases mapped much more tightly relative to the large pelvic vessels. A proposed pelvic clinical target volume to encompass the region at greatest risk of containing occult nodal metastases would include a 2.0-cm radial expansion volume around the distal common iliac and proximal external and internal iliac vessels that would encompass 94.5% of the pelvic nodes at risk as defined by our node-positive prostate cancer patient cohort.

Cervix

 * 15.Nov.05 - Compared with conventional dose prescription methods, inverse planning simulated annealing (IPSA) provides a consistent method of optimization that maintains or improves target coverage while decreasing dose to normal structures. Image-guided brachytherapy and inverse planning improve brachytherapy dosimetry.

title: User:Tdvorak/Red Journal


text: User talk:207.28.99.145

title: User talk:207.28.99.145


text:
Talk:Rhetoric and Composition/Grammar

Umm.. I think we're going to want to do more here than just link to LEO!!--Mattbarton.exe 17:33, 11 November 2005 (UTC)

title: Talk:Rhetoric and Composition/Grammar


text:
User:Delfeld

Hello!

I mostly here to add to Blender 3D Wikibook, but other things may come along.

Neal Delfeld

title: User:Delfeld


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Talk:Rhetoric and Composition/Advanced Topics

This page needs to be broken up into proper sections like the other two introductory chapters. --Mattbarton.exe 18:03, 11 November 2005 (UTC)


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Talk:Rhetoric and Composition/Analyzing Assignments

This is looking good, though some better formatting would make it easier to read. --Mattbarton.exe 18:04, 11 November 2005 (UTC)

Dennis G. Jerz, 01 Dec 2005. What about putting a brief intro to Bloom's Taxonomy here? I think if a student were to ask the professor, "Where on Bloom's Taxonomy would you like me to focus," that would be a great way to open up a discussion about expectations. I think that would be more useful than the alphabetical listing, since a student who doesn't find the particular key words used by his/her instrutor will be lost in the current format. I don't want to undo the hard work that someone else put into making the list, though. I've posted a Bloom's Taxonomy handout at this address: http://jerz.setonhill.edu/writing/style/taxonomy.htm

Shelly T-P, 13 Dec 2005. Would you recommend including this link to Bloom's Taxonomy? I am not familiar with it myself.

assignments
I put what I thought were basic assignments for a beginning English course, which is who I feel the audience is for this page. Old versions of this page had more specialized assignments which I think were more for upper level students. I won't be offended if there are other assignments that one feels are also "basic" and should be added!

Matt H's edits
Like with other pages, there were lots of sentences that were separated by two spaces, so I deleted the unnecessary space when appropriate.

I tried to eliminate wordiness when possible, and I deleted, or at least revised, many exclamatory sentences! In fact, I got quite the thrill from stroking the Delete key while staring in the face those exclamation marks! (Hopefully my doing so hasn't neutered the book's fun-lovin' spirit.)

Overall, the page length seems appropriate, the tone seems fairly consistent, and the prose and organization are coherent. The "Finishing the Assignment" section got me thinking, though, about whether we want to label sentences that begin with, for instance, "Interpret," or "Examine," as "questions."

(For example: "Knowledge: This becomes evident in how well you remember the subject matter, such as the major ideas, dates, places, events, etc. Questions may begin with: Identify, describe, examine, when, where, who."

Can a group of words that begins with "Identify" be considered a question? I'm probably splitting hairs but figured this issue might be worth discussing.

Additional Guidelines
I feel as though this page currently constitutes a fair summary of the general process of analyzing assignments. That being said, I believe it could use a few more "basic" writing assignment samples, as well as some further insight into the actual steps one would take when first looking into the task at hand (i.e. brainstorming, resolving unfamiliar/confusing wording, etc.). Once that is finished, some basic form editing should clean it all up quite nicely.--IMFlaherty (discuss • contribs) 22:21, 1 November 2012 (UTC)


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UNIX Computing Security/Principles and policies

Suggested topics: education, risk management and enforcement, government security levels (C2, &c.)

Computing security as it applies to UNIX is usually taken to mean protection of a UNIX-based computing system against unauthorized access to information or services on that system, including viewing, copying, modifying or destroying data.

But security can also apply to unauthorized attempts to deny appropriate individuals access to the stored information through loss of availability. Security is also used to manage privacy on a system, whether by confirming the identity of a person who performed an action, and by allowing individuals to maintain control of private information.

Providing security to a system is not a goal so much as it is an ongoing process. At least at present, a UNIX computing system can never be made fully secure. However by continually applying a series of security measures to the systems, the net risk to the system can be brought to a minimum.

Legal issues
A necessary element of system security is the legal system. The threat of prosecution is an important element in deterring an unlawful intrusion or activity, particularly in the circumstance where the system is serving as a component of a company business or when the loss of important information can have significant consequences. It is not even necessary for a system to be compromised in order to have business consequences. A business service can be rendered inoperative for a period of time, costing a firm a significant source of income.

To allow successful prosecution of unlawful activities against a computer system, forensic evidence must be available to demonstrate that a crime occurred. This necessitates the use of logging to track activities and events on the system, and the protection of these logs against tampering. This also includes the need to make periodic backup copies of files on the system on secure media, as frequently as once per day if feasible. In the event of a direct compromise through the hardware, unmodified physical evidence may also be needed, including camera records, witnesses, and so forth.

It can be important during the prosecution to demonstrate that you were performing on-going active measures to prevent inappropriate access, rather than just initiating monitoring in the particular circumstance. So logging and auditing need to be part of the standard security measures. In addition, a carefully-worded legal warning notice needs to be presented prior to login so that the potential intruder can not claim ignorance. Even a greeting message presented prior to login can be used as a legal defense. Finally, due diligence in securing your system can help demonstrate that an inappropriate intrusion was willful and dedicated, rather than as a result of curiosity.

Sarbanes-Oxley
The Sarbanes-Oxley Act of 2002 was a significant piece of legislation designed to help prevent corporate financial fraud. Although computing security was not a factor in the events that resulted in this act, the legislation has had an indirect impact on security requirements. The law imposes accounting requirements and control practices on U.S. companies, or at least those that are publically owned. Requirements for accurate financial records have been strengthened, resulting in the need for control of all aspects of how financial information is processed.

Computing security became relevant due to a provision in Sarbanes-Oxley requiring disclosure of potential liabilities that might impact the bottom line. Events that resulted in the compromise of key computing systems can have a significant impact on the company business. Three of the most relevant sections of Sarbanes-Oxley for computing security are:

 * Section 302 — Certification of the completeness and accuracy of financial reports by the CEO and CFO.
 * Section 404 — Management assessment of internal controls, which must be reported to the SEC each year.
 * Section 409 — Real time disclosure of information.

Due to these requirements, attention to computing security has became an important factor. The act requires companies to disclose when their financial information has been tampered with, describe the measures used to protect the data, and safeguard the information used to track the information security. Companies that are required to disclose that they have poor security practices could prove an uninviting investment, which can affect their stock value. This has brought an increased, and in some cases much-needed attention to computing security in many commercial companies.

System management
Applying security measures is a constant trade-off between maintaining the usefulness of a system and keeping it secure. Each new security measure will further restrict activities on a system, and is likely to be met with resistance by the users. So the system operators must weigh the risks of data loss versus less utility, and decide whether the extra measures are worth the trade-off.

The Administrator of a UNIX system has a significant ability to reduce security risks by properly configuring the operating system to enable security features. In many instances the operating system as shipped by a vendor is applied with a weak security configuration. It requires careful examination of the system to control or eliminate these weaknesses, and neglecting to apply an appropriate restriction can leave a system vulnerable to exploitation.

Once a system has been properly secured, it will still require steady maintenance and monitoring to keep it that way. New exploitations are constantly being discovered, and the administrator will need to stay on top of remedies for newly discovered vulnerabilities. Doing so may require periodic application of new patches, additional changes to the system configuration, or simply an assessment of the risk and determining a means to manage it.

User education
Unfortunately, individual actions by users on a UNIX system can result in a net increase in the security risk. So, in addition to monitoring potentially harmful actions by users, some education of the users is needed. This education includes raising security awareness, training users against certain types of harmful actions, and demonstrating useful tools that can enhance the security of their data.

Determining whether an individual is authorized to have access to the information is an essential component of UNIX system security, and requires access control policies, secure methods of verifying identity, and methods of storing and transmitting credentials. The identity of the individual is used to determine the information they can access, and their ability to modify information on the system.


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UNIX Computing Security/Access authorization

In order to connect to a UNIX-based system and perform activities, a user must have an account. This account must have a unique numerical identifier, which is associated with the account name, or username. The account also has a password, which is string known to the user by which the account access is authenticated when accessing the system. The username and password are normally sufficient to connect a user to the system.

Users can have multiple accounts on the same system, or accounts on different systems. Each account can use a different name, if they are on the same system, or share a common name across multiple systems. Depending on the person or institution operating the systems, the individual users may be able to choose their account names, or they may be assigned a name. Typically an assigned name will be based on the person's actual name, and will be a unique identifier on the system.

Login
The username is also the login name, which means that it is the name that the user types on the keyboard when prompted for a login. On UNIX systems it is a requirement that the first character of the username be an alphabetical character. The case of the character matters: "Joe1234" is a different login name than "joe1234". In most cases the account begins with a lower case character by convention. The remainder of the login name can consist of numbers, alphabetical characters, or an underscore. Thus an asterisk or colon character is invalid for a login name. Accounts with these special characters can cause problems with certain system functions, such as delivering electronic mail. So these characters are usually prohibited on many UNIX systems.

UNIX systems are typically delivered with a set of system accounts for performing special operations. These may include such accounts as,  ,  ,  , or. The  account has special capabilities that grant the user enhanced privileges, and so precautions are usually enforced to prevent its acquisition by unauthorized individuals. More on this later.

/etc/passwd
The information for UNIX accounts is stored in a text file located at. This file contains information for one account per line, and each line is subdivided into fields that are separated by colons. The meaning of the fields is as follows:

When a user gains an account, they are provided with a default password so that they can login. When they connect to the system they will be prompted for the login name, followed by a prompt for the password. If the system is configured correctly, the user can then enter their provided password and it will not appear on the display when it is typed. (Some systems will print an asterisk for each password character, while others will not show anything.) If the password is valid, the user will be allowed access to the system. (They may be prompted to immediately change their password to something only they know.)

The system stores the password in the  file in an encrypted form. UNIX uses an encryption technique called a one-way hash. This means that the password is encrypted using a technique that that does not have a known decryption method. That is, there is no efficient means to determine the password based on the encryption string.

Each time the user logs on, their input password is encrypted and compared to the encryption in the  file. If the two match then the user is allowed access. If the two do not match then access is refused and the user is prompted again to login. (Each connection allows multiple attempts in case the user accidently types the login name or password incorrectly.) Note that the password is also case sensitive, so accidently forgetting to turn off the  key may result in access denial.

If there is a format error in the  file, the system commands are unable to read entries further down in the file. If a user is unable to log on to a system, this could be the reason why. (This is why it is important for the  account to always be the first entry, so that the System Administrator can log in and correct issues with the   file.) UNIX systems can include a command called   that can be run to check for format problems with the   file. It is a good idea to run this from time to time to make sure potential problems haven't been introduced.

When editing the  file, the   command uses a locking mechanism to prevent another administrator from editing the same file at the same time. (Simultaneous edits can result in changes from one operator overwriting changes from another operator, an unfortunate situation where file locking is not available on multi-user systems.) It is a good habit for all System Administrators to use the  command, assuming they are versed in the use of.

Selecting a password
Once a user is logged on to a system, they can change their password by means of the  command. The user will then be prompted for their current password, then they will be prompted twice for the new password selection. (The redundant prompt is to make sure that the user didn't accidently mistype the new password the first time.) After the new password is accepted, the encrypted password field will be updated in the user's account entry in the  file.

The password is a key element of the system's security that is used to verify a user's identity. For this reason it is vital that the password be selected so that it is difficult to guess. Simple, easily-guessable passwords have frequently been the cause of unauthorized access, and there exist programs that can attempt to gain access to a system through trial and error of commonly selected passwords.

Here are some examples of typical passwords that can make it relatively easy to guess:

 * The person's name
 * The name of their child
 * A birthday
 * Simple words such as "guess" or "password"
 * A place name
 * The person's phone number
 * Common keyboard patterns such as "qwerty"
 * The name of the computer
 * A word spelled backwards
 * The same as one of the above followed by a single digit

Modern UNIX systems have security configurations that provide some measure of strength checking when a password is set or changed. For example, a password may be required to be at least eight characters in length, and include one or more upper-case and lower-case letters, a number, and a special character (such as *, $, #, %, &c.) These measures can make a password much more difficult to determine. Wherever possible it is advisable to implement such features to ensure the selection of strong passwords.

When a user has an account on multiple systems, they may choose to use the same password on each of the systems in order to make it easier to remember. Unfortunately this means that if the password on one system is determined by another person, they may be able to gain unauthorized access to the other systems as well. This possibility is difficult for the System Administrator to guard against, except by educating the user and discouraging the use of passwords on multiple systems.

Unauthorized login attempts
Unfortunately there are individuals who may attempt to gain unauthorized access to a system by trying to use another individual's account. They may resort to surreptitious means to obtain the proper login from a user, such as observing them at the keyboard during login, using social engineering to trick an operator or user into giving them access, or by setting up a spoofing program that mimics normal login.

Another method used to obtain unauthorized access is to attempt to guess the login and password. Normally the login is printed on the screen during access, so the individual may already know the account name. However the password should be kept concealed on the screen. If a weak password has been selected by the user, however, it may still be possible to guess the password.

To make the task of guessing a password difficult, most UNIX systems have limits built into the login system. The first limit puts a time delay in between each failed login attempt, so that it takes much longer to attempt each guess. Another limit is to restrict the number of login attempts before disconnecting the session. In addition, the failed login attempts can be recorded in log files, such as. The log files can be periodically checked by the System Administrator to check for unusual failed login activities (such as hundreds of attempts in a day).

Groups
In addition to the account identifiers, UNIX can qualify access to system resources on the basis of group membership. Each group can contain multiple accounts, and an account can belong to one or more groups. An account will have a default group to which they belong, such as, and this information is stored in the   file.

The  command is used to switch your group without changing your account. As long as the group exists and your account belongs to the group, you will be changed to the selected group name. You would now have access privileges appropriate for that group.

The group is used to manage information or resources that are shared by multiple people. It is normally used to obviate the need for shared accounts, which is considered bad security practice. Wherever possible the System Administrator should require the use of a group for providing access to shared resources, and avoid the use of a shared account. There are two reasons for this. The first is that it is nearly impossible to track or audit the activities of an individual who is a member of a shared account. The second is that it is much more difficult to terminate access by a specific individual to a shared account.

/etc/group
The information for UNIX groups is stored in a text file located at. This file contains information for one group per line, and each line is subdivided into fields that are separated by colons. The meaning of the fields is as follows:

To belong to additional groups beyond the default, an account must be added to the appropriate members list. Here is a brief example of an  file:

root::0:root other::1:root bin::2:bin users::20: secrets::30:billy_bob,sally_sue,frederick

Each line in the file describes a group. In this example, the accounts billy_bob, sally_sue, and frederick are all members of the group secrets, even though their default group is users. Note that if a group has a password, a user can use the password to change to that group even if he or she is not a member.

As with the  command for the   file, there is usually a   command available that can be used to check the format of the   file. It is good practice to use this command to check that format errors have not been introduced.

Identifiers
UNIX uses integer values to track and store access information. The user identifier, or, is an identifier that corresponds to a user's account on a UNIX system. This identifier is used internally by the system to determine ownership of potentially sensitive data and processes. When the system needs to list the owner of a data file or process, it normally maps the identifier back to the account name in the  file before presenting the information.

The value of the  can typically range from 0 up to one less than the maximum integer supported on the system. (Negative identifiers, particularly -2, are for special purpose use only.)

User identifiers are usually assigned beginning with 100, and each new account is added by assigning a previously unused identifier. When an account is deleted for some reason, the account entry is removed from the  file. However this may result in files created by that account having an unassigned. A new account created subsequently may be assigned the previous, making that new user the owner of the files created by the previous account. In order to prevent this eventuality, the System Administrator needs to perform periodic maintenance to locate files that lack a valid account.

Default accounts
During the initial installation of a system, the vendor media can load selected default accounts. These accounts are generally used for system administration and maintenance. By convention the user identifiers 0 through 99 are nearly always reserved for these accounts, such as,  ,  ,  , and so forth. In many instances, most of these accounts have their passwords disabled, and the  is used for system files or processes.

The root account in particular, which has a uid of zero (0), is a special account that has higher privileges than any user. It is often referred to as the superuser account. Special precautions need to be taken to prevent inappropriate individuals from gaining access to this account, and much of the security-related configuration of a UNIX system is intended to prevent this eventuality.

In certain environments it may be necessary for certain administrative capabilities to be shared among more than one operator. The drawback to this, of course, is that becomes more difficult to maintain a secure system when multiple people have superuser access. It can also make it more difficult to perform a root-cause analysis when something on a system breaks.

There are several methods to help reduce the risk of a shared superuser access, although it can never be reduced to zero. The first is to configure a system so that the root account can not be accessed directly. Instead the operator must log on using their user account, then  (switch-user) to the superuser account. This can provide an audit trail of when the superuser account was accessed and by whom. It also helps to insulate the system from attempts to break into the superuser account directly. Instead a user account must first be compromised, and then the superuser account.

A more sophisticated approach to limiting the superuser account access requirement is through the use of role-based access control. This allows designated user accounts to perform a limited set of actions that are normally restricted to the root account. (An example of this would be a trusted user account that is allowed to make revisions to a server's printer configuration.) There are a number of tools available, both in open source and from vendors, that can be used to provide role-based access control capabilities. This topic will be covered in more detail in later chapters.

Shadow password file
While a user's password is stored as an encrypted string on UNIX systems, anybody who can read the encrypted value may be able to use a program to test various commonly-used passwords and see if they match. That is, the program can try a series of guesses and encrypt them to see if they match the value in the user's password field. The program can also use a dictionary of words and encrypt each one and compare them in turn to each encrypted password on a system.

To make this task somewhat more difficult for a password guessing program, the encrypted password includes a random, two-character "salt". This random salt value will most likely result in a different encryption string value even when the passwords for two accounts match. As a result the program must recompute the encryption string for each guess and for every account. Nonetheless a modern UNIX system can still crunch through a large number of guesses in a relatively short amount of time, making a brute-force attack quite feasible on a system where a password consists of a simple word.

When the password is formed using a rule, such as two words separated by a number, the task becomes slightly more difficult. However a wily individual may have considerable computing resources at his or her disposal, so guessing a weak password may just be a matter of time. (An example of such a program is called, which can be used by the System Administrator to periodically check their user's passwords for guessable values.)

In order to forestall this technique, the encrypted passwords can be stored in a separate file, commonly known as the shadow password file. The contents of the shadow password file can only be read by the  account, and the password field of the   file is replaced by an asterisk. The implementation of this feature will vary depending on the UNIX vendor. The shadow password is located at  on Sun systems and under   on HP-UX systems. With the encrypted password "shadowed" in this manner, the task of guessing a password is rendered much more difficult.

Account management
Under construction...

 * Paperwork & records
 * Modifying passwords
 * Password aging
 * Disabling accounts