A B Ainsworth

C Avram

J Sheard

The Relevance of Computing Research Historythe Monads-PC: a Case Study

Keywords: Monads, Monads-PC, Monash Museum of Computing History

Introduction

The Monash Museum of Computing History (MMoCH) was started in 2001 to preserve the computing history of Monash University and present this history to members of the University and the general public. The Museum provides material for teaching staff on campus. To meet these objectives, the museum has been collecting computing material directly relating to Monash University including original hardware and software used on campus as well as biographical material relating to staff and students participating in IT related areas of study. To help with current teaching requirements, the museum is building a small computing reference collection to demonstrate key computing technologies. The museum has a research program directed towards the provenance of artefacts in the collection and also biographical material on people related to computing developments and use at Monash University.

In 2006 the MMoCH opened a new permanent exhibition. In view of our teaching commitments, the display has a mixture of typological approach and thematic ideas. During the design phase of the display, the staff felt it was important to show and important for students to see a multiplicity of objects because many computers and calculators appear to have similar functions but achieve this through different architecture.

To meet the design philosophy of the museum, the display is divided into four sections.

1. The role of calculating devices in the pre-development of computers 2. The development of computers within a chronological framework of photographic images of Australian society 3. The Ferranti Sirius computer which was the first computer installed at Monash University 4. Monash computer legends (a select rotating biographical display on people connected with Monash University and computing)

As part of the Monash computer legends display, the original display was updated in 2008 with biographies on Professor David Abramson and Professor John Rosenberg who both studied and worked at Monash University during their careers. Research for this display highlighted a project, entitled the MONADS project that both professors had participated in during their studies. A customdesigned computer built during this project at Monash University, called the MONADS-PC, was located in 2008 at the University of Ulm, Germany. Through the efforts of Professor David Abramson and Jörg Siedenburg (Dipl.-Ing.), Faculty of Computer Science, Department SGI, University of Ulm, the MONADS-PC was shipped back to Australia and donated to the MMoCH. The donation of the MONADS PC required some months of investigation into the provenance of the computer to establish the computer's date and history and then place its significance within the development of the whole MONADS project.

This work provides an interesting case study on the relevance of researching computer history and the lessons it can provide for approaches in modern research. The Monads project was an innovative project over more than 20 years, involving cross-institutional and international collaboration. Its work developed new approaches to both hardware and software. What were the successful features of the project? How can this be applied to modern research?

The Monads Project

In 1976 several staff and students in the Department of Computer Science, Monash University started a new research project called the MONADS project. It was initiated and directed by Professor J.L. Keedy. This was the start of more than twenty years of research under this umbrella project.

The MONADS Project had a number of different phases including software and hardware research. After the project was started at Monash University, research continued at different institutions including the University of Newcastle and later the University of Sydney as Monash staff and researchers took up positions at other institutions and worked with a number of researchers and students. Professor Keedy worked during the 1980s and 1990s in Germany as well as in Australia and moved aspects of the MONADS Project to the Technical University of Darmstadt and later to the University of Bremen and the University of Ulm. Over the life of the project, many different people have contributed to the various aspects of the project.

Of particular interest to the MMoCH is the development of the MONADS-PC in the 1980s. The MONADS-PC is a micro-programmed workstation designed to support a very large virtual memory, capability-based addressing and information hiding software modules. The MONADS-PC was designed in the mid 1980s at Clayton campus, Monash University by Professor David Abramson and Professor John Rosenberg. A number of MONADS-PC models were constructed at Monash University and the University of Newcastle during the 1980s. The computer donated to the MMoCH was sent to Germany from Australia in 1990.

For a project overview, Professor Keedy has created a detailed technical discussion of the project at http://www.monads-security.org/ with an interesting list of publications and thesis work associated with the project at different phases.  "To develop practical software engineering techniques for improving the specification, design, implementation and maintenance of large software 106 systems, i.e. systems involving tens, hundreds and even thousands of man years of effort.  To develop practical techniques for guaranteeing the security (i.e. the confidentiality, integrity and availability) of information held in large computer systems." 3 The name MONADS was taken from a word created by the philosopher Leibniz. Leibniz used the word to describe the basic elements that the world is constructed from. It was Leibniz's belief that these elements were unable to interact with each other but worked together in perfect harmony (in his view because they each had a spark of the deity!) 4 . The Monads program adopted this principal for software systems (but without a spark of the deity as John Rosenberg remarked 5 ). As Keedy states, "We believe that systems should be composed of stable and relatively independent components which have minimal interactions with each other. This can be achieved in practice by rigorously applying the informationhiding principle." 6 The project was also focused on the security of the information held in a computer and this developed into work on producing hardware that would support a capabilitybased addressing system. Capability-based addressing is a method for a computer to have controlled access to 'capabilities'. The computer stores information in the memory but with capability addressing, these are protected objects and access to them is controlled by the kernel. This effectively allows for selective access to the memory by different users depending upon the software parameters.

In the project, the team developed hardware, languages, operating systems and software engineering techniques to meet its objectives. As such, it brought together specialists able to contribute to all of these areas.

In their 1985 article, Rosenberg and Abramson caution that the project appears to have a strong emphasis on hardware, computer architecture and operating systems as the main objectives. The different phases of the project were given sub-names with MONADS as the common feature. The project can be divided into: Monads I, Monads II, Monads II/2, Monads III, MONADS-PC, Distributed MONADS-PC, Monads MM.

There was also considerable work made in the area of languages including: Leibniz, L1.

Later projects that have succeeded the MONADS Project include the SPEEDOS Project which was initiated by Prof. Keedy and his research group in 1998 at the University of Ulm, Germany. Another project called S-RISC was commenced after 1993 8 .

MONADS Project Stages

MONADS I

The project commenced with the first stage that became known as MONADS I. Work was started by three Monash University PhD students -John Rosenberg, Ramamohanarao (Rao) Kotagiri and Ian Richards under the supervision of Professor J.L. Keedy. The Monads project team worked on both software and hardware developments to meet the needs of the project. The department's HP2100A minicomputer was modified to suit their requirements. It had already been modified by a postgraduate student, Rob Hagan, under the supervision of Professor Chris Wallace, in 1975 for their work on virtual memory. By 1976 the HP2100A memory hardware had been modified to support a demand-paged virtual memory. More adjustments were made in 1977 and laid the foundation for the hardware for the MONADS project 9 .

John Rosenberg started work on creating the MONADS hardware kernel to be installed on the HP2100A. This Hardware Kernel was applied to four major areas: Memory Management, Process Management, I/O Management and Protection. This work was in part funded by a grant from the Australian Research Grants Committee (number F77/15337 I) and a Monash University Postgraduate Scholarship 10 . It is significant that this ARGC grant was probably the first one awarded by this Committee in the field of computer science research 11 . The MONADS I used the modified hardware and the new software in a pilot version by 1978. However it did not meet the requirements of the project. To undertake the principle of informationhiding, the team worked on a software system that broke up information into small information hiding modules, these then performed specific tasks. At this stage of the project, the MONADS I hardware did not work effectively with the software modules and was inefficient12 .

Rosenberg, Kotagiri and Richards all completed their PhD thesis work on elements of the MONADS Project. John Rosenberg submitted in 1979, Rao Kotagiri completed his thesis in 1980 while Ian Richards finished in 198113 .

MONADS II and II/2

Work commenced in 1980 on a new stage, a report in 1982 acknowledged the team working on the project. They were listed as: J.L. Keedy, J. Rosenberg, D. Abramson, David Rowe, Peter Dawson, Mark Evered, Mark Halpern, Ed Gehringer, Glenda Patterson, Kotagiri Ramamohanarao, Ian Richards, John Thomson, Brian Wallis, John Wells14 . This group represented a mixture of PhD students and Honours students as well as staff.

In 1980 David Abramson, then a PhD student at Monash University, started work on MONADS II with funding from the Australian Research Grants Committee (ARGC Grant F80/15191), the Australian Computer Research Board and the Monash Special Research Fund (Grant no. SC18/79). This stage of the project also used the modified HP2100A computer. The processor in this model could develop 31-bit virtual addresses which were converted into physical memory addresses by the virtual memory manager. It had 400Kb of physical memory. The system also used 2 x 5Mb disk drives, 1 x 80Mb Winchester disk and a terminal multiplexor. The processor could also communicate with another unmodified HP2100A and a VAX 11/780 computer which they were using at the time for program compilation15 . Abramson in his 1983 paper described the new hardware component of the project for the MONADS II as complete but noted several problems and described a new system called MONADS II/2. There was a move away from the HP2100A to using a Z8000 micro-computer with two Intel Multibuses. MONADS II/2 proposed a larger addressing range moving from 31-bit to 47-bit and a larger physical memory 16 . At this time, Professor J.L. Keedy completed his unsupervised staff PhD thesis in 1982, focusing on software engineering in the MONADS computer architecture17 .

MONADS III

The project continued to evolve and work started on MONADS III. However it was not completed due to the resignation of two main researchers from Monash University -Professor Keedy and Dr (later Professor) Rosenberg. Ed Gehringer, visiting Monash University as a Fulbright Fellow under the Australian-American Education Foundation from May 1981-January 1982 from Carnegie Mellon University, undertook to write a description of MONADS III system architecture. This became MONADS Report No. 1220 .

MONADS-PC

Professor John Rosenberg and Professor David Abramson started work on the MONADS-PC in 1984 at Monash University. They designed and built the first MONADS-PC, a single board computer. The MONADS-PC computer had 60-bit virtual addresses with capability registers and an efficient address translation unit. The project was a combination of hardware and software research to implement a paged virtual memory which was accessed by large addresses. There were several examples of the MONADS-PC built. The MONADS project continued using this hardware.

The MONADS-PC was designed to meet the need to limit the number of errors that occur when multiple programs interact within the computer and access the same data. Data can be stored permanently in the computer on the disc or temporarily in the memory while the computer is in active use. To meet the hardware requirements for this process, the hardware had to be modified and several new elements were added to allow the computer to map where all the addresses were located at the same time. The MONADS-PC was one of the first systems to place all storage in a single, distributed, virtual address space. The different programs and their specific use of the data are isolated into modules and they are controlled by software that only allows interaction by certain users. No module can change data in another module, so if an error occurs in one module, the error is not copied into another module. The MONADS-PC was a multi-user system and could support 5 or 6 terminals at the same time.

The project also developed a new computer language called Leibniz to provide the instructions for the control of the modules. This work was designed by Mark Evered who commenced at Monash University but transferred to Darmstadt under the supervision of Professor Keedy. He was awarded his PhD entitled "Leibniz A Language to Support Software engineering" in 1985 from the Technical University of Darmstadt.

David Abramson developed the circuit board for the first MONADS-PC. The prototype is currently on loan to MMoCH and on display in the Legends display section which features a brief biography on both Professor Abramson and Professor Rosenberg. The board has an unusual circuit-board construction method which employs insulated wires embedded in epoxy-resin that allowed very high-density circuit board layouts. Apart from the custom-designed board, the MONADS-PC was constructed from commercially available components21 . There was some suggestion that the research could have some commercial future. Professor Rosenberg mentioned this idea in a 1985 article in The Age newspaper but cautioned that it would take two or three years to become a commercially viable product24 . Commercial production of the MONADS-PC did not eventuate.

and his assistants at the University of Bremen29 . The MONADS Project was a key feature of their research programs. Work at Ulm has grown in new directions and they created a new project entitled SPEEDOS again focusing on security. Although now retired, Professor Keedy still maintains his research interest in SPEEDOS.

Summary

The MONADS project was a collaborative effort that spanned several academic institutions and combined the skills of both hardware and software specialists. The concepts developed by the team opened up development of hardware with new work in early networking, expanding hardware from 32-bit to 64-bit and major work on security software with information hiding, distributed virtual memory and capability addressing.

This research project represented the collaboration of computer departments from three Australian universities as well as three universities in Germany and a visiting scholar from the United States. Many of the key participants have continued to work in computer science research as well as take on academic roles. When Professor Keedy proposed the project in 1976, Monash University had only recently started to look at the possibilities of computer science research. It is an acknowledgment of Professor Keedy's perception of the possibilities of this research area in software engineering that the MONADS project continued for over twenty years and encouraged young computer scientists to undertake research.

Monash University played a key part in this significant research project providing both support through funding as well as encouraging research staff and students to participate as part of their academic development. The project led to new levels of research in computer science with researchers undertaking major developments in both the hardware and software components. The University encouraged this work and showed a continuous commitment to the concept of research from the beginning of the project.

The MONADS project had a long lasting influence on many of the researchers and many continued to work in the field of computer science with senior careers in academia. The project took on the name MONADS to define their approach to software being made of separate entities that work in harmony but do not interact. The actual process of the project itself proved to be the opposite of this concept with the concurrent work by different researchers in hardware and software continually interacting to create a functioning computer in the MONADS-PC.

The historical study of this project has provided a number of valuable insights into the role of different features contributing towards a successful computer project and the relevance of these insights for the modern researcher. It highlights several factors for a successful project.

1. The selection and definition of the scope of a new project, its relevance to computer development 2. The selection of personnel to undertake research and their long term commitment to developing new ideas and implementing them 3. The value of collaboration between different researchers; in this case, not just one field of computer study but also across several institutions 4. The support of the parent institution for the value of long term research as well as government financial support thought specific grants For the Monash Museum of Computing History, this study was initiated by the acknowledgment of two successful Monash University graduates in the field of computing in our biographical display area. The subsequent donation of the MONADS-PC led to a greater understanding of the role of computer research both at Monash University and at other institutions. This historical study of a computer project has much wider implications and is relevant to our approach to modern computer research.

Figure 1 :

 1 Figure 1: MMoCH Director, Ass. Professor Judy Sheard and Professor David Abramson with the MONADS-PC in the Museum exhibition space 2008.Source: Chris Avram, MMoCH (MONADS-PC, MMoCH collection item 2009.032)

8

  See http://www.monads-security.org 9 Keedy, J.., Wallace, C.S.,Rosenberg, J., Ramamohanarao, K., Richards, I., and Georgiades, A. (1978) A Collection of Papers on the Monads Operating System. Monads Report No. 1, Monash University -Department of Computer Science, February 1978: p.3-4. 10 Keedy, J.., Wallace, C.S.,Rosenberg, J., Ramamohanarao, K., Richards, I., and Georgiades, A. (1978) P.25-26. 11 Email from Prof. J.L. Keedy to Ass. Prof Judy Sheard 14 November 2012.

  Professor Keedy was appointed to the Chair in Operating Systems at the Technical University of Darmstadt in Germany in 1982 18 . He did not have the facilities to work on hardware developments but concentrated on software components of the project from 1982 to 1985. Dr Rosenberg also resigned from the project in 1982 and he left Monash University for two years, returning in 1984 19 . Work continued at Monash University on a scaled down version of MONADS III, called the MONADS II/2.

Figure 2 :

 2 Figure 2: Professor Les Keedy, Professor David Abramson and Professor John Rosenberg photographed in 1982 with the HP2100A and MONADS Series II hardware, Monash University. Source: David Abramson

  Work by Abramson and Rosenberg in the mid-1980s was largely carried out using resources from within Monash University's Department of Computer Science. In 1986 the project obtained funding from the Australian Research Grants Scheme as well as a collaborative research grant with the CSIRO Division of Information Technology 22 . Dr Rosenberg and Dr Abramson submitted a paper to the 18 th Hawaii International Conference on System Sciences in 1985 on the MONADS-PC research. The paper was entitled "MONADS-PC -A Capability-Based Workstation to Support Software Engineering" and received the Best Paper Award in the Hardware Track. It was the only Australian paper presented at the conference 23 .

Figure 3 :

 3 Figure 3: Photograph of Professor David Abramson and Professor John Rosenberg in 1985 with a version of the MONADS-PC, Monash University. Source: Monash University Archives MONPIX IN633.

3 Background to Computer Research at Monash University and Start of MONADS Project

  Keedy moved from England to become a Lecturer in the Department in 1974. He had previously worked with ICL (International Computers Ltd) in England 2 . In 1976 Keedy created the MONADS Project drawing on his experiences at ICL. Professor Keedy, in his notes regarding the development of the project, defines the original aims of the project as:

	Monash University was established in 1958 and its first computer was installed in
	1962. The Monash Computer Centre operated the computing equipment and also
	undertook some teaching. The University later developed an academic department in
	the Faculty of Science for teaching computer science at the Clayton campus during
	the 1960s. Professor Chris Wallace was appointed as Chair of Information Science in
	December 1967. The first subject was Information Science 303 for third year
	students.

Seven honours students were enrolled in 1970. This was the beginning of a computer science research program. During 1972 the Department purchased its own HP2100A computer which was later modified for various research projects. In 1975 the Department's name was changed to Computer Science. This department grew to have a complete subject range through all levels of students and established a worldrecognised research program. In 1990 the University created the Faculty of Computing and Information Technology which is now the Faculty of Information Technology 1 .

It was during the developmental stage of teaching and research at Monash University that Dr. J.L. (Les)

[START_REF] Rood | From Ferranti to Faculty: Information Technology at Monash University, 1960 to 1990[END_REF]. From Ferranti to Faculty: Information Technology at MonashUniversity, 1960University, to 1990. Monash University ePress, Melbourne. Australia.

J.L. Keedy biography http://www.jlkeedy.net/biography.html Accessed January 17, 2011.

Abramson, D.A. 1983 "The MONADS II Computer System," Proc. 6 th Australian Sciences Conference, Sydney, February 1983, pp1-10. p.2.

Keedy, J.L. The Monads Project. p.8 list of PhD Theses, http://www.monads-security.org/ Accessed January 17, 2011

[START_REF] Keedy | A Collection of Papers on the MONADS Operating System[END_REF] The MONADS Operating System p.5 in[START_REF] Keedy | A Collection Of Papers On The Monads Operating System[END_REF] A Collection of Papers on the MONADS Operating System. MONADS Report No.1 Monash University. -Department of Computer Science, February 1978

Abramson 1983 p.3

Abramson 1983 p.7

Keedy, J.L. The Monads Project. p.8 list of PhD Theses , http://www.monads-security.org/ Accessed January 17, 2011.

Keedy, J.L. The Monads Project p.2, http://www.monads-security.org/ Accessed January 17, 2011

Rosenberg J and Abramson D.A. (1985) "MONADS-PC -A Capability-Based Workstation to Support Software Engineering", Proceedings of Eighteenth Annual Hawaii International Conference on System Sciences, January 2-4, 1985 pp.222-230. p.230, http://messagelab.monash.edu.au/Publications/Publication?action=download&upname=mon ads_sesupport.pdf Accessed September 14,

[START_REF] Gehringer | MONADS: A Computer Architecture to Support Software Engineering[END_REF] MONADS: A Computer Architecture to Support Software Engineering. MONADS Report No. 12. Monash University -Department of Computer Science.

TheAge (1985) "International spotlight on Monash pair", The Age, Tuesday, February 5, 1985 p.30, Melbourne.

[START_REF] Review | New Computer Helps Wipe Out Bugs[END_REF] "New Computer Helps Wipe Out Bugs" No. 1 -86 p.1-2; http://www.adm.monash.edu.au/records_archives/assets/docs/pdf/monash-review/1986-.pdf Accessed January 17, 2011

[START_REF] Williams | Australian hardware impresses Hawaiian conference[END_REF] "Australian hardware impresses Hawaiian conference", Computer Weekly, January 25, 1985.

TheAge (1985) "International spotlight on Monash pair", The Age, Tuesday, February 5, 1985 p.30, Melbourne.

Email from David Koch to Barbara Ainsworth December 17, 2012.

Email from Professor Keedy to Ass. Prof Judy Sheard November 14, 2012.

Keedy, J.L. Dr. (2011) The Monads Project, p.2. http://www.monads-security.org Accessed December 24, 2011.

Keedy, J.L. Dr. (2011) The Monads Project. p.6 http://www.monads-security.org Accessed December 24, 2011.

University of Ulm, Germany-Department of Computer Structures http://www.uniulm.de/uni/vereoff/fb/93-95/133.html.en Accessed March 1, 2012

Acknowledgements

This research project was conducted at the Monash Museum of Computing History, Monash University, Australia. MMoCH would like to acknowledge the contributions of Professor David Abramson, Professor J.L. Keedy and Professor John Rosenberg for their time and valuable comments on the Museum's research for provenance details on the MONADS project and the MONADS-PC in the MMoCH collection.

Professor Keedy installed a MONADS-PC at the University of Bremen after he took up his position there in 1988 and then transferred it to the University of Ulm in 1993. This model of the MONADS-PC was built by David Koch at the University of Newcastle, New South Wales specifically for Professor Keedy using a custom circuit board. Some other units were partially built at the University of Sydney by David Koch while he was seconded to Sydney about 1991. Although these were not completed, the extra units (possibly one or two) and other custom circuits were sent to Germany as well 25 . David Koch's completed MONADS-PC was sent to Germany in 1990. Professor Rosenberg travelled to Germany and helped to install the computer with local research staff. This example of the MONADS-PC was donated back later to the Monash Museum of Computing History in 2008. Another MONADS-PC was built by Jörg Siedenburg at the University of Ulm 26 .

Distributed MONADS-PC and MONADS MM

The MONADS Project was moved to the University of Newcastle, New South Wales in 1985. Professor Keedy had returned from Germany to establish the Department of Computer Science at the University of Newcastle 27 . He was later joined by John Rosenberg who moved to Newcastle as Senior Lecturer. They continued to work on the project and worked with research student Frans Henskens and also David Koch.

The MONADS-PC hardware could be connected to other computers and work on the system started to look at Local Area Networks.


Giovanni A Cignoni
email: cignoni@di.unipi.it

Fabio Gadducci
email: gadducci@di.unipi.it

Using Old Computers for Teaching Computer Science

Keywords: computing history, computing museums, teaching

Research on the history of computing often needs to adopt experimental archaeology methods: the rebuilding of old hardware and software requires us to proceed by hypothesis and experimentation. This is one of the key assets of the HMR project, whose main goal is the study of Italian computers from the Fifties and Sixties. The results obtained by the HMR research are made accessible to the public through exhibitions and workshops held at the Museum of Computing Tools of the University of Pisa. The visitors of the Museum, mainly students from middle and high schools, are introduced to the basic concepts of computer science through fascinating old machines. The paper reviews some of the results of the HMR project and presents how historical computers, either preserved at the Museum or rebuilt by HMR, are shown to the public and help to teach principles and mechanisms of computer science.

Introduction

Computer science is a still young discipline. However, given the rapid evolution of technologies, it is already difficult to preserve the memory of its protagonists and of their results. In a few years, hardware and software become out-dated. Before they are recognized as relics of the past, they risk being forgotten and lost. The History of Computing thus needs commitment and resources.

Such a history, however, should not be just a celebration of the past. Among other things, the charm of vintage computers and their stories may be of help in order to make scientific and technological disciplines more appealing for students. Indeed, old machines are both odd and fascinating: they may stimulate young people to invest time in the study of computer science and electronics; or, at least, they may provide them with the basis to be informed users and consumers of technology.

The teaching of computer science requires a suitable array of examples. However, today hardware and software are often too complex to be properly dealt with. On the other hand, the computers of the past offer us real-life examples: they are intriguing because of their age or of their historical role, yet they are simpler, built on a human scale (often literally) and understandable in all their details.

The paper presents the experience of a fruitful interaction between historical research and scientific dissemination. The HMR project [START_REF]Hackerando la Macchina Ridotta[END_REF] at the Department of Computer Science of the University of Pisa investigates the history of Italian informatics by adopting methods and techniques that stress the technological aspects of the discipline. The Museum of Computing Tools [2] of the same University provides precious pieces of its collections.

Section 2 briefly describes the HMR project, its methodologies and main results. Section 3 is devoted to some of the machines in the collection of the Museum: it presents how, during the guided tours, they are narrated and illustrated in order to explain, in addition to their history, the underlying mechanisms by which they work. Section 4 describes the reconstructions made by HMR and in particular the simulator of the Macchina Ridotta, the very first Italian computer, designed and built in Pisa in 1957. The presentation is focused on the use of the simulator in the educational workshops offered to schools by the Museum.

The HMR Project

HMR is a research project focusing on the recovery of the history and the technology of old computerswith a special attention to Italian ones. HMR has historical and technological goals: on the one hand, HMR aims at recovering the facts concerning the development of those early machines; on the other hand, HMR plans to rebuild past computers through simulations and replicas. HMR is a project of the Department of Computer Science of the University of Pisa, ongoing since the beginning of 2006.

The project acronym stands for Hacking the Macchina Ridotta, with an explicit reference to the hacker culture [START_REF] Levy | Hackers: Heroes of the Computer Revolution[END_REF]. In fact, in order to rebuild the computers of the past a full understanding of their technology is mandatory. A superficial knowledge does not suffice: all the details need to be explored and understood with curiosity and commitment. These same words are written in the definition of hacker which is given e.g. in the Internet Glossary RFC 1392 [START_REF]Internet Users' Glossary[END_REF].

The Macchina Ridotta (MR, meaning Smaller Machine in Italian) was the very first computer designed and built in Italy: it made its début in Pisa in 1957. The MR was a result of the same project that in 1961 delivered the more famous Calcolatrice Elettronica Pisana (CEP, meaning Pisa Electronic Computer).The MR has been the first computer investigated by the HMR project. Today HMR has widened its research goals, but the MR still remains in the acronym in order to highlight the origins and the initial accomplishments of the project.

In fact, the MR almost completely disappeared from the history of Italian computer science [START_REF] Cignoni | Rediscovering the Very First Italian Digital Computer[END_REF]. It was the in-depth investigation of the recovered MR documentation that made possible to rediscover it and, by rebuilding its technology, to understand its achievements and its relevance. From an historical point of view, HMR added a new chapter to the annals of Italian computer science.

In March 2008, HMR celebrated the 50 th anniversary of the MR with a lecture in the course on History of Computer Science. MR's birthday was chosen as the date written on the MR User Manual: March 1, 1958. Actually, the MR has been running since July 1957, but in early 1958 it started to deliver computing services to Italian research projects: a clear sign of its functionality and reliability. The Manual was concrete evidence and a valuable symbol of the presence of users external to the small group of computer pioneers that build the MR, such as the researchers of the Physical Chemistry Institute which programmed the MR for their purposes. A few months ago, the 55 th anniversary of the MR was remembered by Google BlogSpot [START_REF] Cignoni | Experimental Archaeology of Computer Science[END_REF].

Information technologies developed quickly. The hardware was (and still is) superseded year after year. Old machines are forgotten, often scrapped. The other half of computer science, the software, was encoded in formats that rapidly became obsolete, the storage media degrade with time and today they are often unreadable. The same documentation is often lost, and maybe it was incomplete since the beginninga long-standing bad habit of computer scientists. The protagonists of the events are often still with us, but their memories cannot keep track of the many details of such extremely complex systems. There is the need of digging in warehouses and archives as well as reassembling the pieces, in order to compare them with other contemporary computers and with the technological knowledge of the time. The gaps must be filled with assumptions and hypotheses which have to be checked and validated by experiments through simulations and replicas. The methodologies adopted by HMR [START_REF] Sale | The Colossus Rebuild Project[END_REF] and other rebuilding projects in the world, like for instance [START_REF] Burton | Replicating the Manchester Baby: Motives, Methods, and Messages from the Past[END_REF] and [START_REF] Auerbach | European Electronic Data Processing -A Report on the Industry and the State of the Art[END_REF], are thus reminiscent of those adopted in experimental archaeology.

The early Pisa computers are still the main objectives of HMR: there is still much to discover and rebuild. However, additional investigations focused on a range of topics, from the story of the first Olivetti machines, with their connections with industrial design and arts, to the evolution of personal computing from the early arithmometers of the XIX century to today portables. In all those cases, the results are also finalized to the dissemination and popularization of computer science.

The Computers at the Museum

Over the years, by rescues, recoveries, acquisitions, or donations, the Museum of Computing Tools of the University of Pisa gathered a relevant collection. Among the most valuable pieces, some of them are unique, such as the 1961 CEP and the Olivetti 9104, especially designed by the Institute for Computing Applications in Rome. Other important artefacts are some early Sixties Olivetti products and a number of machines that, starting with the first arithmometers, made the history of personal computing.

HMR works with the Museum to narrate computers and their histories from both a scientific and a technological perspective. The computers of the past, explored as relics or rebuilt as actual or virtual replicas, are the protagonists of teaching and popularization initiatives that are unique in Italy. The following sections describe the most significant pieces that, in the activities performed at the Museum, have been used as examples to tell the stories and the technologies of computer science.

Historical data and technical information about the early Italian computers have been collected using as much as possible first-hand sources. For the CEP, the main reference is the original documentation in the Archives and Libraries of the University and the CNR. Useful sources are represented by foreign reports such as [START_REF] Blachman | The State of Digital Computer Technology in Europe[END_REF] and [START_REF] Parolini | Olivetti ELEA 9003: Between Scientific Research and Computer Business[END_REF].

The literature on Olivetti computers mainly focuses on corporate events [START_REF]ELEA 9003 -C. Olivetti & C. -Milan, Italy[END_REF]. Reliable technical data are less documented, even if they can be found in foreign reports, as the files on ELEA 9003 [START_REF] Goldstein | ELEA 6001 -C. Olivetti & C SpA. -Laboratorio di Ricerche[END_REF] and 6001 [START_REF]La lunga marcia di Mauro Picone[END_REF] recorded by the U.S. Navy, or the correspondence between Canepa (head of the Olivetti Observatory of New Canaan) and Picone (director of INAC in Rome) in [START_REF] Leclerc | From Gamma 2 to Gamma E.T.: The Birth of Electronic Computing at Bull[END_REF].

An overview of the evolution of those machines is out of the scope of our paper. For a recent summary in English of the main events concerning the CEP project, as well as the ELEA series, we refer the reader to [START_REF] Cignoni | Rediscovering the Very First Italian Digital Computer[END_REF] and the references therein.

Bull Gamma 3, 1953

The Gamma 3 Bull was built in 1952 [START_REF] Cignoni | Il restauro del software di sistema della Macchina Ridotta del 1956[END_REF]. It is one of the first European examples of commercial electronic machines, relevant to the history of French computing as well as to the Italian: Olivetti went into the computer business in 1949 by signing an agreement for the distribution in Italy of the Bull machines.

Since 1931 Bull started to produce electromechanical tabulators based on the patents of Norwegian Fredrick Rosing Bull. The Gamma 2 (1951) was the first one equipped with electronic circuits with diodes and vacuum tubes. The Gamma 3 was an immediate development and, in various versions, was produced in about 100 specimens until the early Sixties.

The Gamma 3 is proposed to visitors as an example of machine architecture with separate memories (in technical jargon, Harvard and not Von Neumann), thus, it is not in fact a modern computer. The specimen at the Museum is one of the first models, and the program memory was still made up of a massive plug-board and the software was actually hardware made of wires and pins inserted into the plug-board. Luckily, the complex operation of coding a program was not too frequent: several pre-coded programs were available and "loaded" into the machine directly by changing the plug-board. While showing the details, the most daring visitors are given the opportunity to test the weight of the programs of the Gamma 3!

The Gamma 3 is a witness of other facets of informatics. First of all, it uses punch cards. Second, it is a demonstration of how the market is sometimes independent of the technological level of the product. The Gamma 3 was a success even though it was an outdated product, for the aforementioned architectural characteristics and the odd mix of hardware technologies: alongside the digital electronic circuits, the Gamma 3 features a number of old electromechanical relays circuits.

Olivetti ELEA 6001, 1961

The ELEA 9003 was the first electronic computer produced by Olivetti. While a prototype of the ELEA series was presented at the Milan Fair in 1959, the first units were only delivered during 1960. ELEA 6001 followed a year later. Even if it is a follow-up product, a careful examination reveals a quite interesting machine.

In fact, the 6001 was an evolution of the 9003 designed to make the system more modular and versatile, thus able to satisfy different customers with respect to financial investment and application needs. It shared with the 9003 the general architecture and the set of peripherals, as well as the elegant exterior design by Ettore Sottsass. From a technological point of view, the 6001 introduced microprogrammed control and floating point arithmetic. It was a great market success (about 150 units sold, com-pared with about 40 of 9003), winning also scientific customers (it was e.g. acquired by the University of Padova, by the Politecnico of Turin and by the CNR of Rome).

In the Museum, the 6001 is proposed to the visitor as the final achievement of the series of wise R&D investments that, despite entering late in the market, led Olivetti to set-up a successful Electronics Division in just a few years.

Calcolatrice Elettronica Pisana, 1961

The 1961 CEP was showcased at the Museum. Apart from its historical value, its size and the (faithfully reconstructed) layout of its cabinets offer to visitors the unique experience of walking into a computer and discovering the components and their functions: the same, apart from the dimensions, of today computers.

The "walk" allows one to observe the input/output control board (actually, a 3 meters long rack), to appreciate the individual bits of the ferrite core memory, to recognize the registers of the processor, the read-only memory of the microprogrammed control, and the ALU components, up-to the individual stages of the parallel 36-bit adder.

Depending on the audience, a visit to the CEP may offer different levels of technicalities. The details offered by the Power Supply Unit range from the electrical representation of 0s and 1s to the trade-off between speed and energy consumption obtained by adjusting voltages. The matrix of the micro-programmed control allows the presentation of the mechanisms for decoding and executing machine instructions. The modular design of circuits together with the original instruments used for the construction and maintenance of the CEP provide an opportunity to actually understand what it meant to build a computer in the Fifties.

Due to the financial difficulties met by the project in its final years, the 1961 CEP was completed late and so it was, in some ways, already outdated. In particular, it was not possible to move toward a fully transistorized machine (thus reducing space, power consumption and heat dissipation issues), while this technological leap was taken by Olivetti with its ELEA series. This aspect of the CEP history let the visitors reflect on how risky can be for the technological future of a country to stop the research funding. The "walk" inside the CEP can also involve the visitors in a playful "transistors hunt" to find the few spots where, as a proof of their technological awareness, the Pisa researchers were able to introduce the new electronic components thus discovering other traces of the participation of Olivetti to the CEP project.

Olivetti 9104 CINAC, 1966

In 1955 the CNR National Institute for Applied Computing (INAC) in Rome bought a Ferranti Mark I*. The Ferranti was one of the first European commercial computers, produced since 1951, and a direct descendant of the 1948 Manchester Baby Machine, the first modern computer. The Ferranti INAC was the second computer to operate in Italy, a few months after the purchase by the Polytechnic of Milan of a CRC 102A, which had however less memory and worse performances.

In the early Sixties INAC decided to replace the Ferranti with a more modern machine by entering into an agreement with Olivetti. The new computer was eventually delivered in 1966, when the Olivetti Electronics Division had already been sold to General Electric. It was a one-of-a-kind specimen, identified as Olivetti Elea 9104 and renamed CINAC (for Computer INAC) by the CNR.

The 9104 was derivative of ELEA 4001, an average-size computer that was supposed to replace the ELEA 6001. The project was discontinues after the sale of the Olivetto electronic division to General Electric, but one of its variations, initially called ELEA 4-115, had great commercial success as GE-115.

The agreements between INAC and Olivetti established that the new machine had to be able to completely emulate the Ferranti. The request originated in the wealth of experience and, above all, of software libraries that the CNR Institute had developed in the long term adoption of Ferranti: a heritage that could not be lost and that can be interpreted today as a great attention to backward compatibility.

The emulation layer was extremely faithful: the Ferranti console and one of the typical viewers for the Williams memory banks were cannibalized and interfaced with the 9104, thus fully replicating the way programmers and operators were used to work. The presence of the original pieces of the Ferranti is thus another element contributing to the uniqueness and curiosity of the relic.

In addition, for the more technologically interested, the presence of the viewer of the memory banks is an opportunity to explore the theme of the storage technologies that preceded the ferrite cores, in this case the Williams Tubes adopted by Ferranti.

Vintage Computers that Work Again

A computer should always be shown in working conditions otherwise the exhibition is limited to the historical value of the relics, even if in some cases it is worth at least to appreciate the exterior design. An exhibition of switched off computers is, at best, only half of the story.

There are several ways to revive a vintage computer: restoration, rebuilding, simulation. Whatever the chosen way is, it is always a challenge in terms of time, efforts, and costs. Usually, the first difficulty is to obtain the technical information. As a consequence, the reviving process often needs to proceed by hypotheses and experiments. By applying these methods, HMR produced actual and virtual rebuilds of the MR.

 Replica of the 6 bit adder. Our research found a note reporting the activities of the early months of 1956. One of the achievements of those days was the building of a 6 bit adder. Likely, this was the first piece of digital hardware assembled in Italy. We built a replica according to the original blueprints, using components and tools of the period -a few of them recovered from the spare parts of the CEP project.  Educational 6 bit adder. The 1956 adder has a modular structure that makes it suitable for explaining how binary arithmetic works. We thus built a version made by handy parts, which the students may play with. The logic and modular architecture are the same as the original adder, but the electronic implementation today uses components to reduce the size and to work with low and safe voltage.  Simulator of the 1956 MR. Our technological investigation was able to identify two versions of the MR. It was possible to retrieve almost all the documentation of the first design, dated July 1956, in particular a large collection of logical, electronic and mechanical blueprints. Due to the availability of its documentation, this version of the MR has been the first target of a virtual rebuild.  Simulator of the 1957 MR. The 1956 design was heavily modified and the MR completed in 1957 was very different from its initial version. Unfortunately, little documentation remains of this MR version: a short user manual, a concise technical report and few photos. This second simulator fully the machine core (CPU and memory) and the manual control panel. Work is in progress for the simulation of the I/O devices, including hardware errors and borderline situations. A detailed discussion of the problems faced by HMR in the rebuilding of the MR is in [START_REF] Burton | Replicating the Manchester Baby: Motives, Methods, and Messages from the Past[END_REF], while in [18] the use of the simulator of the 1956 MR for the "restoration" of its system software is presented. In the following we focus on the use of the 1957 MR simulator in the teaching workshops held at the Museum. The virtual MR is used to revive the look and feel of an old computer and to show and discuss some of the principles and mechanisms according to which past and present computers work. Understanding the role of all the QCM components is the result of a long process of analysis based on the recovered documents: scientific papers, project reports, internal notes and blueprints. The documentation collected in the Archives is fragmentary. Moreover, many documents are extremely concise. In a few cases we found only draft versions of documents and blueprints which still had errors, not to mention old fashioned terminology and notations.

Rebuilding the MR was like solving a big technological puzzle: putting pieces together, some recovered from the documents, other derived by assumptions made according to the knowledge of the time. The simulation, before becoming useful for dissemination, has been the key tool for testing the reconstruction hypotheses.

The methods and simulation tools used by the HMR project are actually a result of current research in modelling and simulation [19] and they are part of the teaching carried out at the Simulation Course held for the master degree in Applied Computer Science of the University of Pisa.

The MR Simulator as a Teaching Workbench

The MR simulator is used in the workshops offered by the Museum to middle and high schools. The aim of the workshops is to introduce the concepts and the mechanisms of computer science by showing a fascinating device:

 most of the interaction with the MR is through the QCM, by reading the IN and IM displays and by setting data and instructions on TM and TI; everything is done bit-wise, a great exercise in binary arithmetic;

 the MR had a quite small set of instructions, all using the same format that is very simple and rational -today we would call the MR a RISC machine; this makes the MR easy to be presented, understood and used in a short time;  the way the MR is operated exposes all the mechanisms that today remain hidden behind friendly user interfaces; from loading code into memory to starting it by manually executing unconditional jumps, all the events happening in a computer when a program is launched are fully disclosed;  MR, as practically all computers of its time, was not conceived to interact with the user during program execution; however, by using the ability to set and activate breakpoints, it is possible to make pseudo-interactive programs useful to explain the basics of human-machine interfaces. A typical demonstration session with the simulator starts by the execution of single instructions directly from TI, by setting the 5 bits (10 to 14) of the instruction code and the 10 bits (0 to 9) of the operand. A further step is to run simple programs that allow use of the MR as a simple calculatorwith display and keyboard in binary.

For a "gaming" experience, a program transforms the MR into a classical slot machine. Besides the fun, the example is interesting for the kind of user interaction that it implements. Moreover, the underlying random number generator uses an algorithm that was developed in the mid-Sixties, that is, about ten years after the MR time. This is used as an opportunity to reflect on the universality of computers and to recall fundamental concepts of computation such as the Turing equivalence.

The simulator is also extremely accurate in reproducing in real-time the performance of the MR. It is possible to run benchmarks and measure how fast the MR waswith about 70 KIPS, it was quite a good runner for the time.

Finally, the simulator carefully reproduces also the look and feel of an old computer. Indeed, its accuracy offers an intriguing side-effect, debunking (and explaining) the classic movie representation of computers packed with blinking lights. In the case of the MR, the lights on the QCM were implemented by cold cathode gas-filled triodes (type Z50T). Their times of ionization/de-ionization were, respectively, 50 and 200 μs, much longer than the clock cycle of the MR that, depending on of the type of microinstruction, was 4 or 8 μs. As a result, the lights on the QCM more than blinking, were emitting an incomprehensible and flickering gleam: they were full on or off only when the machine was stopped and the bit values remained constant.

Conclusions and Future Work

Besides any other consideration, the history of computing can be a valuable teaching tool, allowing us to introduce in a soft way basic concepts of computer science to the general public and to students.

The article outlined some of the major results of the HMR project and offered an overview of some of the most significant historic machines preserved at the Pisa Museum of Computing Tools, showing that the reconstructions and the original memorabilia can contribute to the teaching of computer science. The success so far encountered by these initiatives, both in terms of public participation and in the media, seems to confirm the value of this approach.

For the future, we are working to set up a permanent exhibition at the Museum devoted to personal computing, starting from the very first mechanical (yet digital) machines like the XIX century arithmometers, up to the first fully portable computer of the end of the XX century. In the planned setting, the turning point between personal calculators and personal computers will be the Olivetti Programma 101, universally considered a jewel of Italian technology and design. The Museum has in its collections a few P101's, and we hope to be able to restore at least one in working conditions. And, of course, there will be a fully featured simulator.

Fig. 1 :

 1 Fig. 1: The only surviving photo of the Manual Control Panel of the 1957 MR.

Fig. 2 :

 2 Fig. 2: The Manual Control Panel as reproduced by the simulator of the MR.

Acknowledgements

The desk research was carried out in collaboration with the Archives of the University of Pisa and the Library of ISTI-CNR of Pisa. With regard to the archive, a special thanks goes to Daniel Ronco.

The 6-bit adder has been reconstructed in collaboration with the Computer Museum of Novara and the workshops of the National Institute of Nuclear Physics. We remember with great pleasure the days spent working with Andrea Moggi (INFN) and Alberto Rubinelli (the Museum of Novara).

Finally, special thanks go to Elio Fabri, one of the protagonists of the MR, who, with his memories and the documents he preserved, provided us with an invaluable contribution to the understanding of the technologies of the very first Italian computer.

The Control Panel Manual MR 1957

Fig. 1 reproduces the only surviving photo of the Quadro di Controllo Manuale (QCM, literally the Manual Control Panel), that is, the console of the 1957 MR. Fig. 2 presents the virtual QCM as it is reproduced by the simulator. The QCM was the main interaction interface with the MR. Among its main components there are:

 Indicatore del Numeratore (IN, literally numerator display, 10 lights, top right), displaying the binary value of the program counter;  Indicatore della Memoria (IM, literally memory display, 18 lights, under IN), connected to the MR memory to display the binary value of the last written word; however, since the ferrite core memories have to be rewritten after each reading, IM shows also the last read word;  Tastiera della Memoria (TM, literally memory keyboard, 18 vertical switches, under IM), used to bit-wise set a word to be written in memory;  Tastiera delle Istruzioni (TI, literally instruction keyboard, 18 vertical switches, under TM), used to bit-wise set an instruction (for example, in Fig. 2 an unconditional jump instruction to the memory address 100 is set on TI);  Chiavi di Arresto Condizionato (CAC1/2/3, literally keys for conditional stop, 3 vertical switches, bottom left), used to prepare the 3-bit codes that allow to stop the execution of the MR programs at defined breakpoints;  Commutatori dei Modi di Funzionamento (literally switches for working modes, from left to right CNR, CRT, CEI, CAIM, 4 switches with 2 or 3 positions, bottom centre), used in combination to set the MR in different operating modes, such as the step by step execution of programs (by instructions or micro-instructions), the execution of instructions from memory or from TI, the loading of data or programs in memory by connecting I/O devices, in a way we may call direct memory access;  Pulsante di Avviamento (PA, literally start button, bottom right), used to enable the clock pulse generator and to start the working cycle of the MR.


Chris Monk

Computing: Is There a Future in the Past?

Keywords: National Museum of Computing, young people, learning guides

This short summary describes the outcomes from the decision of The National Museum of Computing (TNMoC) to open its doors to visits by students from across the UK. Our experience has inevitably caused us to question the reasons for their visit, the students' understanding of what they see and the relevance their 'day out' has on their understanding of computing.

The Rationale for Opening our Doors to Young People

The Trustees of TNMoC have expressed a clear aim for the museum within its mission statement:

"To collect and restore computer systems particularly those developed in Britain and to enable people to explore that collection for inspiration, learning and enjoyment." Inspiration, learning and enjoyment are at the heart of what we aim to offer through our learning visit programme.

The Experience over the Past Year

The museum has organised a programme for supported visits that is open to schools, colleges and universities. Visits are supported by 'learning guides' and are a combination of a museum tour plus more interactive activities.

Over 3,000 young people visited the museum over the past year. Their ages ranged from as young as seven year olds through to mature students well into their twenties. Typically most are studying GCSE (aged 15/16) and post 16 courses (aged 17/18). Arriving from all parts of the UK, the students typically stay for 4 to 5 hours. They can be a group of 6 or 60 with most between 15 and 25 in number. Why Do They Come?

The visiting group's teachers express a wish for their students to better understand the history of computing, to support;  the school curriculum generally, (typically pre 16s)  the specification of a qualification, (usually GCSE or A/AS Level)  the teacher's desire to extend and broaden their student's understanding and outlook, (e.g. to encourage a take up of Computing at GCSE)

What Do Young People Think About What They See?

It is important to understand how young people perceive the past and how they make sense of technologies way beyond their life experience. We attempt to encourage them to 'be there' and understand why computing developed in one direction compared to another. The visits are becoming less a collection of 'facts' associated with big machines and more a story that we can illustrate through our collection.

Young people have little experience of any 'past' through which to rationalise what they see. We try to help them get a better sense of time, social context, problem solving and the pace of development.

Their world is essentially 'now'. The computing of today is very bright, attractive and at the heart of their day to day experience. We find it important to link the past to the now, to help capture their attention and interest.

We want young people to better understand why we are where we are and the reasons for that journey. It is vital that they perceive a 'story' not a collection of facts and we want them to understand that they are living in the latest chapter of that story, certainly not at its end.

The past is offering students a chance to 'be there' and think about why decisions were made that have such great impact on what we do today. Where possible we ask students to use the 'story so far' to think about what might come next. 'Future gazing' is an increasingly important outcome for the museum. We would like to do more to listen to young people's predications, desires and fears for the future of computing.

What Next For Our Visits?

TNMoC realises that presenting the past is not enough. We have a responsibility to interpret and explain why we are where we are. Through our visit programme for students we are developing an experience, which will;

 Improve their knowledge and understanding of the past and its story,  Encourage their perception of building on the shoulders of those from the past,  Develop their respect and understanding for conservation and restoration,

Figure 1 :

 1 Student visit to the National Museum of Computing

 Offer opportunities that will, over time, ensure a new generation of enthusiasts, experts and volunteers that can continue looking after the history of computing, Continuing, developing and improving our learning visit programme is an important contribution by TNMoC to securing the future for 'the past' through the next generation of young people and beyond.

Links and References:


Martha E Crosby
email: crosby@hawaii.edu

Using Events from the Past to Inform the Future

Keywords:

Knowledge of the history of computing is an important and relevant topic, particularly for computer science students. Inventions are usually created to solve a particular problem, yet the product evolves and is used for entirely different purposes. Knowing the origin and context gives students additional ways to recall that knowledge. The various implementations make old ideas current. One can infer the past from the future, and from the fact that predictions by most people associated with computer technology have not been particularly accurate. The examples in this paper illustrate how many of the artifacts that existed in early computer and communication systems informed the future.

Introduction

Knowledge of the history of computing is an important and relevant topic, particularly for computer science students. However, students need to know why they are learning something in order to relate it to information they possess. Lee argues: "little of our literature or open records contains information on the motivation, the innovation and the decision making that led to commercial products, to new methodologies, and significant research results" (Lee, 1998, p. 11). Students need to understand the relevance of each discovery and its position in a continuum. Often the stories associated with the evolution of the specific technology are as important (or at least as interesting) as the contribution itself. Inventions are often created to solve a particular problem, yet the product evolves and is used for entirely different purposes. The various implementations are what make old ideas current. If the purpose is not to invent but to adapt an idea, the background of the idea's inception may also play a role in the new implementation. Once the idea is clearly understood, it is possible to extrapolate it into a new context. What makes ideas current is not the novelty of the idea in itself but the way in which it is presented. If students are able to see discoveries in their time and context they are more likely to rediscover these concepts as they are implemented in current contexts [START_REF] Giangrandi | Numerie Macchine": A Virtual Museum to Learn the History of Computing[END_REF]. There are many ways in which students may benefit from the history of computing. Giangrandi & Mirolo, (2006, p. 79) explain that computer history helps students understand the development of scientific knowledge, to bridge the gap between science and humanities and to enrich cultural background. Other areas where students may benefit from learning the history of computing are presented by (Nakano, Styles, & Draper, 2013, p. 27). They explain that: "employees who have studied the history of computing can relate to older workers, thus reducing the generation gap in information technology." Students who are well versed in the history of computing know the outcomes of what was tried before and they bring different points of view to problem solving. Sometimes, the purpose of an idea changes with the available technologies. Anderson (2012, p. 33) gives an example of repurposing of digitization to adapt it to current times with the following quote: "During the late 20 th century and early 21 st century, letter writing has given way to email, SMS messages, and tweets, diaries have been superseded by blogs (private and public), and where paper once prevailed digital forms are making inroads and the trend is set to continue."

Events from the Past

Although one can infer the past from the future, it is important that students know that predictions by most people associated with computer technology were not particularly accurate. At one time people thought that fifty storage cells would be enough for any imaginable application. In 1959, there were very few electronic digital computers. However, the sentiment at the time was that the number of computers in the United States would easily meet the demand. People said: "Why would anyone ever want to own a calculator?" Of course the mechanical calculators at that time took an entire desk so it was difficult to imagine having one that could fit in your pocket. If it was hard to envision owning your own calculator, the concept of owning your own computer seemed impossible. In early computers, both time and space were limited but even then most people associated with computer technology realized that optimizing one was usually at the expense of the other. This paper discusses adaptions that were made in hardware, software and data communication and how they informed the future.

In the 1800s Joseph Jacquard created a machine to weave complex patterns using punched cards to automate the process. This concept was adapted to computing by Herman Hollerith, while working for the U.S. Census Bureau. In 1890, he developed the Hollerith Tabulating Machine that used punched cards to take the census. Six years later, Hollerith founded the Tabulating Machine Company later named International Business Machines (IBM). Implementations of time-sharing computers using mechanical relays existed at that time and that technology could have been adapted. However, for almost 30 years, IBM's dominance in the computer field led to the predominate use of punched card technology. Modern computers use control units and separate memory functions, a concept that was heavily influenced by a mechanical calculator called the Z1, invented by Konrad Zuse in 1936. That same year Alan Turing created an abstract model that defined mechanical procedures. Turing's concept of an infinite tape that could be read, written on and erased inspired Random Access Memory (RAM) functions. At the University of Iowa in 1939, John Atanasoff and his student Clifford Berry built the first electrically powered Atanasoff-Berry Computer (ABC). It was the first computer to use the binary system, to have memory restored when it was booted and to use vacuum tubes instead of mechanical switches to store data. Although each calculation took about 15 seconds, its design was a model for future computers. At Harvard, from the late 1930s to early 1950s, Howard Aiken designed the Mark series of computers that were primarily used for computations by the U.S. Navy. Grace Hopper, a programmer for Harvard Mark I, removed a moth that caused the computer to malfunction. This event initiated the use of the term "bug" to mean the cause of a program error. At the University of Pennsylvania in 1944, John Mauchley and J. Presper Eckert developed a high-speed electronic digital computer called the Electronic Numerical Integrator and Computer (ENIAC). It was primarily used to calculate weapons settings by the U.S. Government and was operational until 1955. The Universal Automatic Computer (UNIVAC), completed in 1951, was the first commercially successful computer the United States. It was noticed by the public when it only needed 5% of the vote as input to predict that Dwight Eisenhower would win the presidential race.

In the mid-1970s, a special purpose computer built for a chemical company failed to meet specifications and the manufacturers advertised their product in Popular Electronics, a magazine read by many computer enthusiasts. The computer was very primitive but the price finally made it possible for individuals to own a computer. At that time, very few people would have predicted the personal computer movement that followed. Computer languages such as FORTRAN, ALGOL COBOL had been developed in the 1950s, primarily for scientific and business applications. At Dartmouth College in 1964, John G. Kemeny and Thomas E. Kurtz developed a simplified computer language called the Beginners All Purpose Symbolic Instruction Code (BASIC). This was a programming language that could be easily learned giving more people an opportunity to program computers. The BASIC programming language was small and it became the primary language for personal computers. At the same time the personal computer hardware was developing, the addition of application software made the personal computers useful to more people. Since algorithms build on each other, implementations were constantly being adapted to either run faster or use less space. Sorting and searching methods have been continually improved for specific types of problems. Libraries of software are built and improved. Open source mathematical libraries such as SHARE were at first the norm, then for profit application packages gave more people reason to use computers.

In 1961, during the cold war, Baran suggested changing the shape of the national communication network to become a redundant distributed network with no vulnerable central point. Looking into the past and available technologies, he proposed the marriage of computer and communication technologies [START_REF] Ryan | History of the Internet and the Digital Future[END_REF]. Examples that are highly motivating for University of Hawaii (UH) students in this context are listening to audio recordings of locally based computer pioneers telling their stories. For example, W. Wesley Peterson describes his 1961 implementation of cyclic redundancy codes (CRC) in an audio recording. During his narrative he describes how he struggled with the idea. He had figured out how to encode and do parity checks efficiently, then, working with colleagues, everything came together for efficient error detection. He mentions that the CRC codes were used for floppy disk technologies and Ethernet networks. The students are impressed how the CRC codes still remain in use in new storage and transmission technologies. Peterson saw CRC codes, as useful tools for error correction but didn't envision the explosion and wide use and impact that telecommunications would have in the world.

In1971, Norman Abramson, transmitted wireless data packets from a user to a computer network. Those packets, transmitted, between terminals in the engineering building and the computer center at the University of Hawaii, marked the first use of what is now known as an ALOHA channel. ALOHA channels were used in a limited way in 1G first generation mobile phones for signaling and control purposes. The use of ALOHA was expanded in the 1990s by the introduction of SMS texting capabilities in 2G mobile networks, and then even more by the use of General Packet Radio Service (GPRS) in 3G networks in the first decade of this century. It seems clear that the expanding use of smart phones and IP based web traffic in developing 4G networks will lead to an even greater use of ALOHA channels and ALOHA traffic in the next decade. UH students are particularly inspired by the history of the development of ALOHA channels on their own campus, particularly when they see the worldwide application of ALOHA in wireless networks, and satellite data networks.

In 1971, UH researchers and graduate students used primitive tools and with great difficulty provided modern techniques in educational multimedia environments. Researchers at the UH had a grant to bring an experimental computer, developed at UC Berkley, to be the tip for the ARPA network. The computer was called the BCC 500 because it had an architecture that could support 500 interactive users. This was at a time when commercial time sharing computers such as the HP only supported 32 simultaneous users. The communication infrastructure provided by the ALOHA network enabled UH to have many initiatives that are still relevant. Because computers were still very expensive in the early seventies, there was a moratorium on all of the K-12 schools in the state of Hawaii not to buy computers. However, some high school mathematics teachers wanted to teach their students to program. The teachers were able to convince their principals to rent teletypes so they could dial in remotely to the BCC500's BASIC compiler at UH. This enabled high school students from the neighbor islands and other areas of Oahu to learn to write computer programs. The Web Browser Mosaic became available in 1993. That year a graduate student at UH was able to write a thesis comparing the performance of Mosaic to all the other existing search engines and browsers by visiting every node on the Internet. As she traced the historical development of the Internet, she realized that the explosive growth rate of the internet nodes would make her task impossible within the year.

Knowing the origin and context of the computer artifact gives the student more ways to store and recall that knowledge. Many new ideas in computing are often adaptations of previous discoveries. In order to avoid duplication of efforts and reinventing the wheel, learning about history should encompass more than just the factual information. If witnesses of the circumstances from which breakthroughs were developed don't talk about it, people will not have an opportunity to learn from the past. By paying more attention to the past, we can continue to inform the future.