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Parallel ATA

Parallel ATA (PATA), originally AT Attachment, also known as IDE or Integrated Drive Electronics, is a standard interface designed for IBM PC-compatible computers. It was first developed by Western Digital and Compaq in 1986 for compatible hard drives and CD or DVD drives. The connection is used for storage devices such as hard disk drives, floppy disk drives, optical disc drives, and tape drives in computers.

The standard is maintained by the X3/INCITS committee. It uses the underlying AT Attachment (ATA) and AT Attachment Packet Interface (ATAPI) standards.

The Parallel ATA standard is the result of a long history of incremental technical development, which began with the original AT Attachment interface, developed for use in early PC AT equipment. The ATA interface itself evolved in several stages from Western Digital's original Integrated Drive Electronics (IDE) interface. As a result, many near-synonyms for ATA/ATAPI and its previous incarnations are still in common informal use, in particular Extended IDE (EIDE) and Ultra ATA (UATA). After the introduction of SATA in 2003, the original ATA was renamed to Parallel ATA, or PATA for short.

Parallel ATA cables have a maximum allowable length of 18 inch. Because of this limit, the technology normally appears as an internal computer storage interface. For many years, ATA provided the most common and the least expensive interface for this application. It has largely been replaced by SATA in newer systems.

History and terminology
The standard was originally conceived as the "AT Bus Attachment," officially called "AT Attachment" and abbreviated "ATA" because its primary feature was a direct connection to the 16-bit ISA bus introduced with the IBM PC/AT. The original ATA specifications published by the standards committees use the name "AT Attachment". The "AT" in the IBM PC/AT referred to "Advanced Technology" so ATA has also been referred to as "Advanced Technology Attachment". When a newer Serial ATA (SATA) was introduced in 2003, the original ATA was renamed to Parallel ATA, or PATA for short.

Physical ATA interfaces became a standard component in all PCs, initially on host bus adapters, sometimes on a sound card but ultimately as two physical interfaces embedded in a Southbridge chip on a motherboard. Called the "primary" and "secondary" ATA interfaces, they were assigned to base addresses 0x1F0 and 0x170 on ISA bus systems. They were replaced by SATA interfaces.

IDE and ATA-1

The first version of what is now called the ATA/ATAPI interface was developed by Western Digital under the name Integrated Drive Electronics (IDE). Together with Compaq (the initial customer), they worked with various disk drive manufacturers to develop and ship early products with the goal of remaining software compatible with the existing IBM PC hard drive interface. The first such drives appeared internally in Compaq PCs in 1986 and were first separately offered by Conner Peripherals as the CP342 in June 1987.

The term Integrated Drive Electronics refers to the drive controller being integrated into the drive, as opposed to a separate controller situated at the other side of the connection cable to the drive. On an IBM PC compatible, CP/M machine, or similar, this was typically a card installed on a motherboard. The interface cards used to connect a parallel ATA drive to, for example, an ISA Slot, are not drive controllers: they are merely bridges between the host bus and the ATA interface. Since the original ATA interface is essentially just a 16-bit ISA bus, the bridge was especially simple in case of an ATA connector being located on an ISA interface card. The integrated controller presented the drive to the host computer as an array of 512-byte blocks with a relatively simple command interface. This relieved the mainboard and interface cards in the host computer of the chores of stepping the disk head arm, moving the head arm in and out, and so on, as had to be done with earlier ST-506 and ESDI hard drives. All of these low-level details of the mechanical operation of the drive were now handled by the controller on the drive itself. This also eliminated the need to design a single controller that could handle many different types of drives, since the controller could be unique for the drive. The host need only to ask for a particular sector, or block, to be read or written, and either accept the data from the drive or send the data to it.

The interface used by these drives was standardized in 1994 as ANSI standard X3.221-1994, AT Attachment Interface for Disk Drives. After later versions of the standard were developed, this became known as "ATA-1".

A short-lived, seldom-used implementation of ATA was created for the IBM XT and similar machines that used the 8-bit version of the ISA bus. It has been referred to as "XT-IDE", "XTA" or "XT Attachment".

EIDE and ATA-2
In 1994, about the same time that the ATA-1 standard was adopted, Western Digital introduced drives under a newer name, Enhanced IDE (EIDE). These included most of the features of the forthcoming ATA-2 specification and several additional enhancements. Other manufacturers introduced their own variations of ATA-1 such as "Fast ATA" and "Fast ATA-2".

The new version of the ANSI standard, AT Attachment Interface with Extensions ATA-2 (X3.279-1996), was approved in 1996. It included most of the features of the manufacturer-specific variants.

ATA-2 also was the first to note that devices other than hard drives could be attached to the interface: "3.1.7 Device: Device is a storage peripheral. Traditionally, a device on the ATA interface has been a hard disk drive, but any form of storage device may be placed on the ATA interface provided it adheres to this standard."

ATAPI
ATA was originally designed for, and worked only with, hard disk drives and devices that could emulate them. The introduction of ATAPI (ATA Packet Interface) by a group called the Small Form Factor committee (SFF) allowed ATA to be used for a variety of other devices that require functions beyond those necessary for hard disk drives. For example, any removable media device needs a "media eject" command, and a way for the host to determine whether the media is present, and these were not provided in the ATA protocol.

ATAPI is a protocol allowing the ATA interface to carry SCSI commands and responses; therefore, all ATAPI devices are actually "speaking SCSI" other than at the electrical interface. The SCSI commands and responses are embedded in "packets" (hence "ATA Packet Interface") for transmission on the ATA cable. This allows any device class for which a SCSI command set has been defined to be interfaced via ATA/ATAPI.

ATAPI devices are also "speaking ATA", as the ATA physical interface and protocol are still being used to send the packets. On the other hand, ATA hard drives and solid state drives do not use ATAPI.

ATAPI devices include CD-ROM and DVD-ROM drives, tape drives, and large-capacity floppy drives such as the Zip drive and SuperDisk drive. Some early ATAPI devices were simply SCSI devices with an ATA/ATAPI to SCSI protocol converter added on.

The SCSI commands and responses used by each class of ATAPI device (CD-ROM, tape, etc.) are described in other documents or specifications specific to those device classes and are not within ATA/ATAPI or the T13 committee's purview. One commonly used set is defined in the MMC SCSI command set.

ATAPI was adopted as part of ATA in INCITS 317-1998, AT Attachment with Packet Interface Extension (ATA/ATAPI-4).

UDMA and ATA-4
The ATA/ATAPI-4 standard also introduced several "Ultra DMA" transfer modes. These initially supported speeds from 16 to 33 MB/s. In later versions, faster Ultra DMA modes were added, requiring new 80-wire cables to reduce crosstalk. The latest versions of Parallel ATA support up to 133 MB/s.

Ultra ATA
Ultra ATA, abbreviated UATA, is a designation that has been primarily used by Western Digital for different speed enhancements to the ATA/ATAPI standards. For example, in 2000 Western Digital published a document describing "Ultra ATA/100", which brought performance improvements for the then-current ATA/ATAPI-5 standard by improving maximum speed of the Parallel ATA interface from 66 to 100 MB/s. Most of Western Digital's changes, along with others, were included in the ATA/ATAPI-6 standard (2002).

x86 BIOS size limitations
Initially, the size of an ATA drive was stored in the system x86 BIOS using a type number (1 through 45) that predefined the C/H/S parameters and also often the landing zone, in which the drive heads are parked while not in use. Later, a "user definable" format called C/H/S or cylinders, heads, sectors was made available. These numbers were important for the earlier ST-506 interface, but were generally meaningless for ATA—the CHS parameters for later ATA large drives often specified impossibly high numbers of heads or sectors that did not actually define the internal physical layout of the drive at all. From the start, and up to ATA-2, every user had to specify explicitly how large every attached drive was. From ATA-2 on, an "identify drive" command was implemented that can be sent and which will return all drive parameters.

Owing to a lack of foresight by motherboard manufacturers, the system BIOS was often hobbled by artificial C/H/S size limitations due to the manufacturer assuming certain values would never exceed a particular numerical maximum.

The first of these BIOS limits occurred when ATA drives reached sizes in excess of 504 MiB, because some motherboard BIOSes would not allow C/H/S values above 1024 cylinders, 16 heads, and 63 sectors. Multiplied by 512 bytes per sector, this totals 528 482  304 bytes which, divided by 1  048  576 bytes per MiB, equals 504 MiB (528 MB).

The second of these BIOS limitations occurred at 1024 cylinders, 256 heads, and 63 sectors, and a problem in MS-DOS limited the number of heads to 255. This totals to 8 422  686  720 bytes (8032.5 MiB), commonly referred to as the 8.4 gigabyte barrier. This is again a limit imposed by x86 BIOSes, and not a limit imposed by the ATA interface.

It was eventually determined that these size limitations could be overridden with a small program loaded at startup from a hard drive's boot sector. Some hard drive manufacturers, such as Western Digital, started including these override utilities with large hard drives to help overcome these problems. However, if the computer was booted in some other manner without loading the special utility, the invalid BIOS settings would be used and the drive could either be inaccessible or appear to the operating system to be damaged.

Later, an extension to the x86 BIOS disk services called the "Enhanced Disk Drive" (EDD) was made available, which makes it possible to address drives as large as 264 sectors.

Interface size limitations
The first drive interface used 22-bit addressing mode which resulted in a maximum drive capacity of two gigabytes. Later, the first formalized ATA specification used a 28-bit addressing mode through LBA28, allowing for the addressing of 228 (268 435  456) sectors (blocks) of 512 bytes each, resulting in a maximum capacity of 128 GiB (137 GB).

ATA-6 introduced 48-bit addressing, increasing the limit to 128 PiB (144 PB). As a consequence, any ATA drive of capacity larger than about 137 GB must be an ATA-6 or later drive. Connecting such a drive to a host with an ATA-5 or earlier interface will limit the usable capacity to the maximum of the interface.

Some operating systems, including Windows XP pre-SP1, and Windows 2000 pre-SP3, disable LBA48 by default, requiring the user to take extra steps to use the entire capacity of an ATA drive larger than about 137 gigabytes.

Older operating systems, such as Windows 98, do not support 48-bit LBA at all. However, members of the third-party group MSFN have modified the Windows 98 disk drivers to add unofficial support for 48-bit LBA to Windows 95 OSR2, Windows 98, Windows 98 SE and Windows ME.

Some 16-bit and 32-bit operating systems supporting LBA48 may still not support disks larger than 2 TiB due to using 32-bit arithmetic only; a limitation also applying to many boot sectors.

Primacy and obsolescence
Parallel ATA (then simply called ATA or IDE) became the primary storage device interface for PCs soon after its introduction. In some systems, a third and fourth motherboard interface was provided, allowing up to eight ATA devices to be attached to the motherboard. Often, these additional connectors were implemented by inexpensive RAID controllers.

Soon after the introduction of Serial ATA (SATA) in 2003, use of Parallel ATA declined. The first motherboards with built-in SATA interfaces usually had only a single PATA connector (for up to two PATA devices), along with multiple SATA connectors. Some PCs and laptops of the era have a SATA hard disk and an optical drive connected to PATA.

As of 2007, some PC chipsets, for example the Intel ICH10, had removed support for PATA. Motherboard vendors still wishing to offer Parallel ATA with those chipsets must include an additional interface chip. In more recent computers, the Parallel ATA interface is rarely used even if present, as four or more Serial ATA connectors are usually provided on the motherboard and SATA devices of all types are common.

With Western Digital's withdrawal from the PATA market, hard disk drives with the PATA interface were no longer in production after December 2013 for other than specialty applications.

Interface
Parallel ATA cables transfer data 16 bits at a time. The traditional cable uses 40-pin female insulation displacement connectors (IDC) attached to a 40- or 80-conductor ribbon cable. Each cable has two or three connectors, one of which plugs into a host adapter interfacing with the rest of the computer system. The remaining connector(s) plug into storage devices, most commonly hard disk drives or optical drives. Each connector has 39 physical pins arranged into two rows (2.54 mm, $1/10$-inch pitch), with a gap or key at pin 20. Earlier connectors may not have that gap, with all 40 pins available. Thus, later cables with the gap filled in are incompatible with earlier connectors, although earlier cables are compatible with later connectors.

Round parallel ATA cables (as opposed to ribbon cables) were eventually made available for 'case modders' for cosmetic reasons, as well as claims of improved computer cooling and were easier to handle; however, only ribbon cables are supported by the ATA specifications.

 * Pin 20: In the ATA standard, pin 20 is defined as a mechanical key and is not used. This pin's socket on the female connector is often obstructed, requiring pin 20 to be omitted from the male cable or drive connector; it is thus impossible to plug it in the wrong way round. However, some flash memory drives can use pin 20 as VCC_in to power the drive without requiring a special power cable; this feature can only be used if the equipment supports this use of pin 20.

 * Pin 28: Pin 28 of the gray (slave/middle) connector of an 80-conductor cable is not attached to any conductor of the cable. It is attached normally on the black (master drive end) and blue (motherboard end) connectors. This enables cable select functionality.

 * Pin 34: Pin 34 is connected to ground inside the blue connector of an 80-conductor cable but not attached to any conductor of the cable, allowing for detection of such a cable. It is attached normally on the gray and black connectors.

44-pin variant
A 44-pin variant PATA connector is used for 2.5 inch drives inside laptops. The pins are closer together (2.0 mm pitch) and the connector is physically smaller than the 40-pin connector. The extra pins carry power.

80-conductor variant

ATA's cables have had 40 conductors for most of its history (44 conductors for the smaller form-factor version used for 2.5" drives—the extra four for power), but an 80-conductor version appeared with the introduction of the UDMA/66 mode. All of the additional conductors in the new cable are grounds, interleaved with the signal conductors to reduce the effects of capacitive coupling between neighboring signal conductors, reducing crosstalk. Capacitive coupling is more of a problem at higher transfer rates, and this change was necessary to enable the 66 megabytes per second (MB/s) transfer rate of UDMA4 to work reliably. The faster UDMA5 and UDMA6 modes also require 80-conductor cables.

Though the number of conductors doubled, the number of connector pins and the pinout remain the same as 40-conductor cables, and the external appearance of the connectors is identical. Internally, the connectors are different; the connectors for the 80-conductor cable connect a larger number of ground conductors to the ground pins, while the connectors for the 40-conductor cable connect ground conductors to ground pins one-to-one. 80-conductor cables usually come with three differently colored connectors (blue, black, and gray for controller, master drive, and slave drive respectively) as opposed to uniformly colored 40-conductor cable's connectors (commonly all gray). The gray connector on 80-conductor cables has pin 28 CSEL not connected, making it the slave position for drives configured cable select.

Multiple devices on a cable
If two devices are attached to a single cable, one must be designated as Device 0 (in the past, commonly designated master) and the other as Device 1 (in the past, commonly designated as slave). This distinction is necessary to allow both drives to share the cable without conflict. The Device 0 drive is the drive that usually appears "first" to the computer's BIOS and/or operating system. In most personal computers the drives are often designated as "C:" for the Device 0 and "D:" for the Device 1 referring to one active primary partitions on each.

The mode that a device must use is often set by a jumper setting on the device itself, which must be manually set to Device 0 (Master) or Device 1 (Slave). If there is a single device on a cable, it should be configured as Device 0. However, some certain era drives have a special setting called Single for this configuration (Western Digital, in particular). Also, depending on the hardware and software available, a Single drive on a cable will often work reliably even though configured as the Device 1 drive (most often seen where an optical drive is the only device on the secondary ATA interface).

The words primary and secondary typically refers to the two IDE cables, which can have two drives each (primary master, primary slave, secondary master, secondary slave).

There are many debates about how much a slow device can impact the performance of a faster device on the same cable. On early ATA host adapters, both devices' data transfers can be constrained to the speed of the slower device, if two devices of different speed capabilities are on the same cable. For all modern ATA host adapters, this is not true, as modern ATA host adapters support independent device timing. This allows each device on the cable to transfer data at its own best speed. Even with earlier adapters without independent timing, this effect applies only to the data transfer phase of a read or write operation. This is caused by the omission of both overlapped and queued feature sets from most parallel ATA products. Only one device on a cable can perform a read or write operation at one time; therefore, a fast device on the same cable as a slow device under heavy use will find it has to wait for the slow device to complete its task first. However, most modern devices will report write operations as complete once the data is stored in their onboard cache memory, before the data is written to the (slow) magnetic storage. This allows commands to be sent to the other device on the cable, reducing the impact of the "one operation at a time" limit. The impact of this on a system's performance depends on the application. For example, when copying data from an optical drive to a hard drive (such as during software installation), this effect probably will not matter. Such jobs are necessarily limited by the speed of the optical drive no matter where it is. But if the hard drive in question is also expected to provide good throughput for other tasks at the same time, it probably should not be on the same cable as the optical drive.

Cable select
A drive mode called cable select was described as optional in ATA-1 and has come into fairly widespread use with ATA-5 and later. A drive set to "cable select" automatically configures itself as Device 0 or Device 1, according to its position on the cable. Cable select is controlled by pin 28. The host adapter grounds this pin; if a device sees that the pin is grounded, it becomes the Device 0 (master) device; if it sees that pin 28 is open, the device becomes the Device 1 (slave) device.

This setting is usually chosen by a jumper setting on the drive called "cable select", usually marked CS, which is separate from the Device 0/1 setting.

If two drives are configured as Device 0 and Device 1 manually, this configuration does not need to correspond to their position on the cable. Pin 28 is only used to let the drives know their position on the cable; it is not used by the host when communicating with the drives. In other words, the manual master/slave setting using jumpers on the drives takes precedence and allows them to be freely placed on either connector of the ribbon cable.

With the 40-conductor cable, it was very common to implement cable select by simply cutting the pin 28 wire between the two device connectors; putting the slave Device 1 device at the end of the cable, and the master Device 0 on the middle connector. This arrangement eventually was standardized in later versions. However, it had one drawback: if there is just one master device on a 2-drive cable, using the middle connector, this results in an unused stub of cable, which is undesirable for physical convenience and electrical reasons. The stub causes signal reflections, particularly at higher transfer rates.

Starting with the 80-conductor cable defined for use in ATAPI5/UDMA4, the master Device 0 device goes at the far-from-the-host end of the 18 in cable on the black connector, the slave Device 1 goes on the grey middle connector, and the blue connector goes to the host (e.g. motherboard IDE connector, or IDE card). So, if there is only one (Device 0) device on a two-drive cable, using the black connector, there is no cable stub to cause reflections (the unused connector is now in the middle of the ribbon). Also, cable select is now implemented in the grey middle device connector, usually simply by omitting the pin 28 contact from the connector body.

Serialized, overlapped, and queued operations
The parallel ATA protocols up through ATA-3 require that once a command has been given on an ATA interface, it must complete before any subsequent command may be given. Operations on the devices must be serialized—with only one operation in progress at a time—with respect to the ATA host interface. A useful mental model is that the host ATA interface is busy with the first request for its entire duration, and therefore can not be told about another request until the first one is complete. The function of serializing requests to the interface is usually performed by a device driver in the host operating system.

The ATA-4 and subsequent versions of the specification have included an "overlapped feature set" and a "queued feature set" as optional features, both being given the name "Tagged Command Queuing" (TCQ), a reference to a set of features from SCSI which the ATA version attempts to emulate. However, support for these is extremely rare in actual parallel ATA products and device drivers because these feature sets were implemented in such a way as to maintain software compatibility with its heritage as originally an extension of the ISA bus. This implementation resulted in excessive CPU utilization which largely negated the advantages of command queuing. By contrast, overlapped and queued operations have been common in other storage buses; in particular, SCSI's version of tagged command queuing had no need to be compatible with APIs designed for ISA, allowing it to attain high performance with low overhead on buses which supported first party DMA like PCI. This has long been seen as a major advantage of SCSI.

The Serial ATA standard has supported native command queueing (NCQ) since its first release, but it is an optional feature for both host adapters and target devices. Many obsolete PC motherboards do not support NCQ, but modern SATA hard disk drives and SATA solid-state drives usually support NCQ, which is not the case for removable (CD/DVD) drives because the ATAPI command set used to control them prohibits queued operations.

HDD passwords and security
ATA devices may support an optional security feature which is defined in an ATA specification, and thus not specific to any brand or device. The security feature can be enabled and disabled by sending special ATA commands to the drive. If a device is locked, it will refuse all access until it is unlocked. A device can have two passwords: A User Password and a Master Password; either or both may be set. There is a Master Password identifier feature which, if supported and used, can identify the current Master Password (without disclosing it). A device can be locked in two modes: High security mode or Maximum security mode. Bit 8 in word 128 of the IDENTIFY response shows which mode the disk is in: 0 = High, 1 = Maximum. In High security mode, the device can be unlocked with either the User or Master password, using the "SECURITY UNLOCK DEVICE" ATA command. There is an attempt limit, normally set to 5, after which the disk must be power cycled or hard-reset before unlocking can be attempted again. Also in High security mode, the SECURITY ERASE UNIT command can be used with either the User or Master password. In Maximum security mode, the device can be unlocked only with the User password. If the User password is not available, the only remaining way to get at least the bare hardware back to a usable state is to issue the SECURITY ERASE PREPARE command, immediately followed by SECURITY ERASE UNIT. In Maximum security mode, the SECURITY ERASE UNIT command requires the Master password and will completely erase all data on the disk. Word 89 in the IDENTIFY response indicates how long the operation will take. While the ATA lock is intended to be impossible to defeat without a valid password, there are purported workarounds to unlock a device. For sanitizing entire disks the built-in Secure Erase command is effective when implemented correctly. There have been a few reported instances of failures to erase some or all data.

External parallel ATA devices

Due to a short cable length specification and shielding issues it is extremely uncommon to find external PATA devices that directly use PATA for connection to a computer. A device connected externally needs additional cable length to form a U-shaped bend so that the external device may be placed alongside, or on top of the computer case, and the standard cable length is too short to permit this. For ease of reach from motherboard to device, the connectors tend to be positioned towards the front edge of motherboards, for connection to devices protruding from the front of the computer case. This front-edge position makes extension out the back to an external device even more difficult. Ribbon cables are poorly shielded, and the standard relies upon the cabling to be installed inside a shielded computer case to meet RF emissions limits.

External hard disk drives or optical disk drives that have an internal PATA interface, use some other interface technology to bridge the distance between the external device and the computer. USB is the most common external interface, followed by Firewire. A bridge chip inside the external devices converts from the USB interface to PATA, and typically only supports a single external device without cable select or master/slave.

Specifications
The following table shows the names of the versions of the ATA standards and the transfer modes and rates supported by each. Note that the transfer rate for each mode (for example, 66.7 MB/s for UDMA4, commonly called "Ultra-DMA 66", defined by ATA-5) gives its maximum theoretical transfer rate on the cable. This is simply two bytes multiplied by the effective clock rate, and presumes that every clock cycle is used to transfer end-user data. In practice, of course, protocol overhead reduces this value.

Congestion on the host bus to which the ATA adapter is attached may also limit the maximum burst transfer rate. For example, the maximum data transfer rate for conventional PCI bus is 133 MB/s, and this is shared among all active devices on the bus.

In addition, no ATA hard drives existed in 2005 that were capable of measured sustained transfer rates of above 80 MB/s. Furthermore, sustained transfer rate tests do not give realistic throughput expectations for most workloads: They use I/O loads specifically designed to encounter almost no delays from seek time or rotational latency. Hard drive performance under most workloads is limited first and second by those two factors; the transfer rate on the bus is a distant third in importance. Therefore, transfer speed limits above 66 MB/s really affect performance only when the hard drive can satisfy all I/O requests by reading from its internal cache—a very unusual situation, especially considering that such data is usually already buffered by the operating system.

, mechanical hard disk drives can transfer data at up to 524 MB/s, which is far beyond the capabilities of the PATA/133 specification. High-performance solid state drives can transfer data at up to 7000–7500 MB/s.

Only the Ultra DMA modes use CRC to detect errors in data transfer between the controller and drive. This is a 16-bit CRC, and it is used for data blocks only. Transmission of command and status blocks do not use the fast signaling methods that would necessitate CRC. For comparison, in Serial ATA, 32-bit CRC is used for both commands and data.

ATAPI Removable Media Device (ARMD)
ATAPI devices with removable media, other than CD and DVD drives, are classified as ARMD (ATAPI Removable Media Device) and can appear as either a super-floppy (non-partitioned media) or a hard drive (partitioned media) to the operating system. These can be supported as bootable devices by a BIOS complying with the ATAPI Removable Media Device BIOS Specification, originally developed by Compaq Computer Corporation and Phoenix Technologies. It specifies provisions in the BIOS of a personal computer to allow the computer to be bootstrapped from devices such as Zip drives, Jaz drives, SuperDisk (LS-120) drives, and similar devices.

These devices have removable media like floppy disk drives, but capacities more commensurate with hard drives, and programming requirements unlike either. Due to limitations in the floppy controller interface most of these devices were ATAPI devices, connected to one of the host computer's ATA interfaces, similarly to a hard drive or CD-ROM device. However, existing BIOS standards did not support these devices. An ARMD-compliant BIOS allows these devices to be booted from and used under the operating system without requiring device-specific code in the OS.

A BIOS implementing ARMD allows the user to include ARMD devices in the boot search order. Usually an ARMD device is configured earlier in the boot order than the hard drive. Similarly to a floppy drive, if bootable media is present in the ARMD drive, the BIOS will boot from it; if not, the BIOS will continue in the search order, usually with the hard drive last.

There are two variants of ARMD, ARMD-FDD and ARMD-HDD. Originally ARMD caused the devices to appear as a sort of very large floppy drive, either the primary floppy drive device 00h or the secondary device 01h. Some operating systems required code changes to support floppy disks with capacities far larger than any standard floppy disk drive. Also, standard-floppy disk drive emulation proved to be unsuitable for certain high-capacity floppy disk drives such as Iomega Zip drives. Later the ARMD-HDD, ARMD-"Hard disk device", variant was developed to address these issues. Under ARMD-HDD, an ARMD device appears to the BIOS and the operating system as a hard drive.

ATA over Ethernet
In August 2004, Sam Hopkins and Brantley Coile of Coraid specified a lightweight ATA over Ethernet protocol to carry ATA commands over Ethernet instead of directly connecting them to a PATA host adapter. This permitted the established block protocol to be reused in storage area network (SAN) applications.

Compact Flash

Compact Flash in its IDE mode is essentially a miniaturized ATA interface, intended for use on devices that use flash memory storage. No interfacing chips or circuitry are required, other than to directly adapt the smaller CF socket onto the larger ATA connector. (Although most CF cards only support IDE mode up to PIO4, making them much slower in IDE mode than their CF capable speed )

The ATA connector specification does not include pins for supplying power to a CF device, so power is inserted into the connector from a separate source. The exception to this is when the CF device is connected to a 44-pin ATA bus designed for 2.5-inch hard disk drives, commonly found in notebook computers, as this bus implementation must provide power to a standard hard disk drive.

CF devices can be designated as devices 0 or 1 on an ATA interface, though since most CF devices offer only a single socket, it is not necessary to offer this selection to end users. Although CF can be hot-pluggable with additional design methods, by default when wired directly to an ATA interface, it is not intended to be hot-pluggable.

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

title: Parallel ATA


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Atari 2600

The Atari 2600 is a discontinued home video game console developed and produced by Atari, Inc. Released in September 1977 as the Atari Video Computer System (Atari VCS), it popularized microprocessor-based hardware and games stored on swappable ROM cartridges, a format first used with the Fairchild Channel F in 1976. The VCS was bundled with two joystick controllers, a conjoined pair of paddle controllers, and a game cartridge—initially Combat and later Pac-Man. Sears sold the system as the Tele-Games Video Arcade. Atari rebranded the VCS as the Atari 2600 in November 1982 alongside the release of the Atari 5200.

Atari was successful at creating arcade video games, but their development cost and limited lifespan drove CEO Nolan Bushnell to seek a programmable home system. The first inexpensive microprocessors from MOS Technology in late 1975 made this feasible. The console was prototyped under the codename Stella by Atari subsidiary Cyan Engineering. Lacking funding to complete the project, Bushnell sold Atari to Warner Communications in 1976.

The Atari VCS launched in 1977 with nine low-resolution games on 2 KB cartridges. The system's first killer app was the home conversion of Taito's arcade game Space Invaders in 1980. The VCS became widely successful, leading to the founding of Activision and other third-party game developers and to competition from console manufacturers Mattel and Coleco. Games grew to use four or more times the storage size of the launch games with significantly more advanced visuals and gameplay than the system was designed for, such as Activision's Pitfall!

By 1982, the Atari 2600 was the dominant game system in North America. However, it faced competition from other consoles such as the Intellivision and ColecoVision, and poor decisions by Atari management damaged both the system and company's reputation, most notably the release of two highly anticipated games for the 2600: a port of the arcade game Pac-Man and E.T. the Extra-Terrestrial. Pac-Man became the 2600's highest-selling game, but was panned for being inferior to the arcade version. E.T. was rushed to market for the holiday shopping season and was similarly panned and became a commercial failure. Both games, and a glut of third-party shovelware, were factors in ending Atari's relevance in the console market, contributing to the video game crash of 1983.

Warner sold Atari's home division to former Commodore CEO Jack Tramiel in 1984. In 1986, the new Atari Corporation under Tramiel released a lower-cost version of the 2600 and the backward-compatible Atari 7800, but it was Nintendo that led the recovery of the industry with its 1985 launch of the Nintendo Entertainment System. Production of the Atari 2600 ended on January 1, 1992, with an estimated 30 million units sold across its lifetime.

History
Atari, Inc. was founded by Nolan Bushnell and Ted Dabney in 1972. Its first major product was Pong, released in 1972, the first successful coin-operated video game. While Atari continued to develop new arcade games in following years, Pong gave rise to a number of competitors to the growing arcade game market. The competition along with other missteps by Atari led to financial problems in 1974, though recovering by the end of the year. By 1975, Atari had released a Pong home console, competing against Magnavox, the only other major producer of home consoles at the time. Atari engineers recognized, however, the limitation of custom logic integrated onto the circuit board, permanently confining the whole console to only one game. The increasing competition increased the risk, as Atari had found with past arcade games and again with dedicated home consoles. Both platforms are built from integrating discrete electro-mechanical components into circuits, rather than programmed as on a mainframe computer. Therefore, development of a console had cost at least US$100000 1975 plus time to complete, but the final product only had about a three-month shelf life until becoming outdated by competition.

By 1974, Atari had acquired Cyan Engineering, a Grass Valley electronics company founded by Steve Mayer and Larry Emmons, both former colleagues of Bushnell and Dabney from Ampex, who helped to develop new ideas for Atari's arcade games. Even prior to the release of the home version of Pong, Cyan's engineers, led by Mayer and Ron Milner, had envisioned a home console powered by new programmable microprocessors capable of playing Atari's current arcade offerings. The programmable microprocessors would make a console's design significantly simpler and more powerful than any dedicated single-game unit. However, the cost US$100–300 of such chips was far outside the range that their market would tolerate. Atari had opened negotiations to use Motorola's new 6800 in future systems.

MOS Technology 6502/6507
In September 1975, MOS Technology debuted the 6502 microprocessor for US$25 at the Wescon trade show in San Francisco. Mayer and Milner attended, and met with the leader of the team that created the chip, Chuck Peddle. They proposed using the 6502 in a game console, and offered to discuss it further at Cyan's facilities after the show.

Over two days, MOS and Cyan engineers sketched out a 6502-based console design by Meyer and Milner's specifications. Financial models showed that even at US$25, the 6502 would be too expensive, and Peddle offered them a planned 6507 microprocessor, a cost-reduced version of the 6502, and MOS's RIOT chip for input/output. Cyan and MOS negotiated the 6507 and RIOT chips at US$12 a pair. MOS also introduced Cyan to Microcomputer Associates, who had separately developed debugging software and hardware for MOS, and had developed the JOLT Computer for testing the 6502, which Peddle suggested would be useful for Atari and Cyan to use while developing their system. Milner was able to demonstrate a proof-of-concept for a programmable console by implementing Tank, an arcade game by Atari's subsidiary Kee Games, on the JOLT.

As part of the deal, Atari wanted a second source of the chipset. Peddle and Paivinen suggested Synertek whose co-founder, Bob Schreiner, was a friend of Peddle. In October 1975, Atari informed the market that it was moving forward with MOS. The Motorola sales team had already told its management that the Atari deal was finalized, and Motorola management was livid. They announced a lawsuit against MOS the next week.

Building the system

By December 1975, Atari hired Joe Decuir, a recent graduate from University of California, Berkeley who had been doing his own testing on the 6502. Decuir began debugging the first prototype designed by Mayer and Milner, which gained the codename "Stella" after the brand of Decuir's bicycle. This prototype included a breadboard-level design of the graphics interface to build upon. A second prototype was completed by March 1976 with the help of Jay Miner, who created a chip called the Television Interface Adaptor (TIA) to send graphics and audio to a television. The second prototype included a TIA, a 6507, and a ROM cartridge slot and adapter.

As the TIA's design was refined, Al Alcorn brought in Atari's game developers to provide input on features. There are significant limitations in the 6507, the TIA, and other components, so the programmers creatively optimized their games to maximize the console. The console lacks a framebuffer and requires games to instruct the system to generate graphics in synchronization with the electron gun in the cathode-ray tube (CRT) as it scans across rows on the screen. The programmers found ways to "race the beam" to perform other functions while the electron gun scans outside of the visible screen.

Alongside the electronics development, Bushnell brought in Gene Landrum, a consultant who had just prior consulted for Fairchild Camera and Instrument for its upcoming Channel F, to determine the consumer requirements for the console. In his final report, Landrum suggested a living room aesthetic, with a wood grain finish, and the cartridges must be "idiot proof, child proof and effective in resisting potential static [electricity] problems in a living room environment". Landrum recommended it include four to five dedicated games in addition to the cartridges, but this was dropped in the final designs. The cartridge design was done by James Asher and Douglas Hardy. Hardy had been an engineer for Fairchild and helped in the initial design of the Channel F cartridges, but he quit to join Atari in 1976. The interior of the cartridge that Asher and Hardy designed was sufficiently different to avoid patent conflicts, but the exterior components were directly influenced by the Channel F to help work around the static electricity concerns.

Atari was still recovering from its 1974 financial woes and needed additional capital to fully enter the home console market, though Bushnell was wary of being beholden to outside financial sources. Atari obtained smaller investments through 1975, but not at the scale it needed, and began considering a sale to a larger firm by early 1976. Atari was introduced to Warner Communications, which saw the potential for the growing video game industry to help offset declining profits from its film and music divisions. Negotiations took place during 1976, during which Atari cleared itself of liabilities, including settling a patent infringement lawsuit with Magnavox over Ralph H. Baer's patents that were the basis for the Magnavox Odyssey. In mid-1976, Fairchild announced the Channel F, planned for release later that year, beating Atari to the market.

By October 1976, Warner and Atari agreed to the purchase of Atari for US$28 million. Warner provided an estimated US$120 million which was enough to fast-track Stella. By 1977, development had advanced enough to brand it the "Atari Video Computer System" (VCS) and start developing games.

Launch and success

The unit was showcased on June 4, 1977, at the Summer Consumer Electronics Show with plans for retail release in October. The announcement was purportedly delayed to wait out the terms of the Magnavox patent lawsuit settlement, which would have given Magnavox all technical information on any of Atari's products announced between June 1, 1976, and June 1, 1977. However, Atari encountered production problems during its first batch, and its testing was complicated by the use of cartridges.

The Atari VCS was launched in September 1977 at US$199 1977, with two joysticks and a Combat cartridge; eight additional games were sold separately. Most of the launch games were based on arcade games developed by Atari or its subsidiary Kee Games: for example, Combat was based on Kee's Tank (1974) and Atari's Jet Fighter (1975). Atari sold between 350,000 and 400,000 Atari VCS units during 1977, attributed to the delay in shipping the units and consumers' unfamiliarity with a swappable-cartridge console that is not dedicated to only one game.

In 1978, Atari sold only 550,000 of the 800,000 systems manufactured. This required further financial support from Warner to cover losses. Bushnell pushed the Warner Board of Directors to start working on "Stella 2", as he grew concerned that rising competition and aging tech specs of the VCS would render the console obsolete. However, the board stayed committed to the VCS and ignored Bushnell's advice, leading to his departure from Atari in 1979. Atari sold 1 million consoles in 1979, particularly during the holiday season, but there was new competition from the Mattel Electronics Intellivision and Magnavox Odyssey², which also use swappable ROM cartridges. The 2019 book They Create Worlds has Atari selling about 600,000 VCS systems in 1979, bringing the installed base to a little over 1.3 million.

Atari obtained a license from Taito to develop a VCS conversion of its 1978 arcade hit Space Invaders. This is the first officially licensed arcade conversion for a home console. Its release in March 1980 doubled the console's sales for the year to more than 2 million units, and it was considered the Atari VCS's killer application. Sales then doubled again for the next two years. According to They Create Worlds, Atari sold 1.25 million Space Invaders cartridges and over 1 million VCS systems in 1980, nearly doubling the install base to over 2 million, and then an estimated 3.1 million VCS systems in 1981. By 1982, 10 million consoles had been sold in the United States, while its best-selling game was Pac-Man at over 8 million copies sold by 1990. Pac-Man propelled worldwide Atari VCS sales to 12 million units during 1982, according to a November 1983 article in InfoWorld magazine. An August 1984 InfoWorld magazine article says more than 15 million Atari 2600 machines were sold by 1982. A March 1983 article in IEEE Spectrum magazine has about 3 million VCS sales in 1981, about 5.5 million in 1982, as well as a total of over 12 million VCS systems and an estimated 120 million cartridges sold.

In Europe, the Atari VCS sold 125,000 units in the United Kingdom during 1980, and 450,000 in West Germany by 1984. In France, where the VCS released in 1982, the system sold 600,000 units by 1989. The console was distributed by Epoch Co. in Japan in 1979 under the name "Cassette TV Game", but did not sell as well as Epoch's own Cassette Vision system in 1981.

In 1982, Atari launched its second programmable console, the Atari 5200. To standardize naming, the VCS was renamed to the "Atari 2600 Video Computer System", or "Atari 2600", derived from the manufacture part number CX2600. By 1982, the 2600 cost Atari about US$40 to make and was sold for an average of US$125 1982. The company spent US$4.50 to US$6 to manufacture each cartridge, plus US$1 to US$2 for advertising, wholesaling for US$18.95 1982.

Third-party development
Activision, formed by Crane, Whitehead, and Miller in 1979, started developing third-party VCS games using their knowledge of VCS design and programming tricks, and began releasing games in 1980. Kaboom! (1981) and Pitfall! (1982) are among the most successful with at least one and four million copies sold, respectively. In 1980, Atari attempted to block the sale of the Activision cartridges, accusing the four of intellectual property infringement. The two companies settled out of court, with Activision agreeing to pay Atari a licensing fee for their games. This made Activision the first third-party video game developer and established the licensing model that continues to be used by console manufacturers for game development.

Activision's success led to the establishment of other third-party VCS game developers following Activision's model in the early 1980s,  including U.S. Games, Telesys, Games by Apollo, Data Age, Zimag, Mystique, and CommaVid. The founding of Imagic included ex-Atari programmers. Mattel and Coleco, each already producing its own more advanced console, created simplified versions of their existing games for the 2600. Mattel used the M Network brand name for its cartridges. Third-party games accounted for half of VCS game sales by 1982.

Decline and redesign
In addition to third-party game development, Atari also received the first major threat to its hardware dominance from the Colecovision. Coleco had a license from Nintendo to develop a version of the arcade game Donkey Kong (1981), which was bundled with every Colecovision console. Coleco gained about 17% of the hardware market in 1982 compared to Atari's 58%. With third parties competing for market share, Atari worked to maintain dominance in the market by acquiring licenses for popular arcade games and other properties to make games from. Pac-Man has numerous technical and aesthetic flaws, but nevertheless more than 7 million copies were sold. Heading into the 1982 holiday shopping season, Atari had placed high sales expectations on E.T. the Extra-Terrestrial, a game programmed in about six weeks. Atari produced an estimated four million cartridges, but the game was poorly reviewed, and only about 1.5 million units were sold.

Warner Communications reported weaker results than expected in December 1982 to its shareholders, having expected a 50% year-to-year growth but only obtaining 10–15% due to declining sales at Atari. Coupled with the oversaturated home game market, Atari's weakened position led investors to start pulling funds out of video games, beginning a cascade of disastrous effects known as the video game crash of 1983. Many of the third-party developers formed prior to 1983 were closed, and Mattel and Coleco left the video game market by 1985.

In September 1983, Atari sent 14 truckloads of unsold Atari 2600 cartridges and other equipment to a landfill in the New Mexico desert, later labeled the Atari video game burial. Long considered an urban legend that claimed the burial contained millions of unsold cartridges, the site was excavated in 2014, confirming reports from former Atari executives that only about 700,000 cartridges had actually been buried. Atari reported a US$536 million loss for 1983 as a whole, and continued to lose money into 1984, with a US$425 million loss reported in the second quarter. By mid-1984, software development for the 2600 had essentially stopped except that of Atari and Activision.

Warner, wary of supporting its failing Atari division, started looking for buyers in 1984. Warner sold most of Atari to Jack Tramiel, the founder of Commodore International, in July 1984 for about US$240 million, though Warner retained Atari's arcade business. Tramiel was a proponent of personal computers, and halted all new 2600 game development soon after the sale.

The North American video game market did not recover until about 1986, after Nintendo's 1985 launch of the Nintendo Entertainment System in North America. Atari Corporation released a redesigned model of the 2600 in 1986, supported by an ad campaign touting a price of "under 50 bucks". With a large library of cartridges and a low price point, the 2600 continued to sell into the late 1980s. Atari released the last batch of games in 1989–90 including Secret Quest and Fatal Run. By 1986, over 20 million Atari VCS units had been sold worldwide. The final Atari-licensed release is the PAL-only version of the arcade game KLAX in 1990.

After more than 14 years on the market, the 2600 line was formally discontinued on January 1, 1992, along with the Atari 7800 and Atari 8-bit computers. In Europe, last stocks of the 2600 were sold until Summer/Fall of 1995.

Console
The Atari 2600's CPU is the MOS Technology 6507, a version of the 6502, running at 1.19 MHz in the 2600. Though their internal silicon was identical, the 6507 was cheaper than the 6502 because its package included fewer memory-address pins—13 instead of 16. The designers of the Atari 2600 selected an inexpensive cartridge interface that has one fewer address pins than the 13 allowed by the 6507, further reducing the already limited addressable memory from 8 KB (213 = 8,192) to 4 KB (212 = 4,096). This was believed to be sufficient as Combat was only 2 KB. Later games circumvented this limitation with bank switching.

The console has 128 bytes of RAM for scratch space, the call stack, and the state of the game environment.

The top bezel of the console originally had six switches: power, TV type selection (color or black-and-white), game selection, left and right player difficulty, and game reset. The difficulty switches were moved to the back of the bezel in later versions of the console. The back bezel also included the controller ports, TV output, and power input.

Graphics

The Atari 2600 was designed to be compatible with the cathode-ray tube television sets produced in the late 1970s and early 1980s, which commonly lack auxiliary video inputs to receive audio and video from another device. Therefore, to connect to a TV, the console generates a radio frequency signal compatible with the regional television standards (NTSC, PAL, or SECAM), using a special switch box to act as the television's antenna.

Atari developed the Television Interface Adaptor (TIA) chip in the VCS to handle the graphics and conversion to a television signal. It provides a single-color, 20-bit background register that covers the left half of the screen (each bit represents 4 adjacent pixels) and is either repeated or reflected on the right side. There are 5 single-color sprites: two 8-pixel wide players; two 1 bit missiles, which share the same colors as the players; and a 1-pixel ball, which shares the background color. The 1-bit sprites all can be controlled to stretch to 1, 2, 4, or 8 pixels.

The system was designed without a frame buffer to avoid the cost of the associated RAM. The background and sprites apply to a single scan line, and as the display is output to the television, the program can change colors, sprite positions, and background settings. The careful timing required to sync the code to the screen on the part of the programmer was labeled "racing the beam"; the actual game logic runs when the television beam is outside of the visible area of the screen. Early games for the system use the same visuals for pairs of scan lines, giving a lower vertical resolution, to allow more time for the next row of graphics to be prepared. Later games, such as Pitfall!, change the visuals for each scan line or extend the black areas around the screen to extend the game code's processing time.

Regional releases of the Atari 2600 use modified TIA chips for each region's television formats, which require games to be developed and published separately for each region. All modes are 160 pixels wide. NTSC mode provides 192 visible lines per screen, drawn at 60 Hz, with 16 colors, each at 8 levels of brightness. PAL mode provides more vertical scanlines, with 228 visible lines per screen, but drawn at 50 Hz and only 13 colors. SECAM mode, also a 50 Hz format, is limited to 8 colors, each with only a single brightness level.

Controllers
The first VCS bundle has two types of controllers: a joystick (part number CX10) and pair of rotary paddle controllers (CX30). Driving controllers, which are similar to paddle controllers but can be continuously rotated, shipped with the Indy 500 launch game. After less than a year, the CX10 joystick was replaced with the CX40 model designed by James C. Asher. Because the Atari joystick port and CX40 joystick became industry standards, 2600 joysticks and some other peripherals work with later systems, including the MSX, Commodore 64, Amiga, Atari 8-bit computers, and Atari ST. The CX40 joystick can be used with the Master System and Sega Genesis, but does not provide all the buttons of a native controller. Third-party controllers include Wico's Command Control joystick. Later, the CX42 Remote Control Joysticks, similar in appearance but using wireless technology, were released, together with a receiver whose wires could be inserted in the controller jacks.

Atari introduced the CX50 Keyboard Controller in June 1978 along with two games that require it: Codebreaker and Hunt & Score. The similar, but simpler, CX23 Kid's Controller was released later for a series of games aimed at a younger audience. The CX22 Trak-Ball controller was announced in January 1983 and is compatible with the Atari 8-bit computers.

There were two attempts to turn the Atari 2600 into a keyboard-equipped home computer: Atari's never-released CX3000 "Graduate" keyboard, and the CompuMate keyboard by Spectravideo which was released in 1983.

Minor revisions
The initial production of the VCS was made in Sunnyvale during 1977, using thick polystyrene plastic for the casing as to give the impression of weight from what was mostly an empty shell inside. The initial Sunnyvale batch had also included potential mounts for an internal speaker system on the casing, though the speakers were found to be too expensive to include and instead sound was routed through the TIA to the connected television. All six console switches on the front panel. Production of the unit was moved to Taiwan in 1978, where a less thick internal metal shielding was used and thinner plastic was used for the casing, reducing the system's weight. These two versions are commonly referred to as "Heavy Sixers" and "Light Sixers" respectively, referencing the six front switches.

In 1980, the difficulty switches were moved to the back of the console, leaving four switches on the front and replacing the previous all lowercase font for the switch labels to fully capitalized wording. Otherwise, these four-switch consoles look nearly identical to the earlier six-switch models. In 1982, to coincide with the release of the Atari 5200, Atari rebranded the console as the "Atari 2600", a name first used on a version of the four-switch model without woodgrain, giving it an all-black appearance. This all-black model is commonly referred to by fans as the "Vader" model, due to its resemblance to the Star Wars character of the same name.

Sears Video Arcade
Atari continued its OEM relationship with Sears under the latter's Tele-Games brand, which started in 1975 with the original Pong. This is unrelated to the company Telegames, which later produced 2600 cartridges. Sears released several models of the VCS as the Sears Video Arcade series starting in 1977. The final Sears-specific model was the Video Arcade II, released during the fall of 1982.

Sears released versions of Atari's games with Tele-Games branding, usually with different titles. Three games were produced by Atari for Sears as exclusive releases: Steeplechase, Stellar Track, and Submarine Commander.

Atari 2800
The Atari 2800 is the Japanese version of the 2600 released in October 1983. It is the first Japan-specific release of a 2600, though companies like Epoch had distributed the 2600 in Japan previously. The 2800 was released a short time after Nintendo's Family Computer (which became the dominant console in Japan), and it did not gain a significant share of the market. Sears previously released the 2800 in the US during late 1982 as the Sears Video Arcade II, which came packaged with two controllers and Space Invaders. Around 30 specially branded games were released for the 2800.

Designed by engineer Joe Tilly, the 2800 has four controller ports instead of the two of the 2600. The controllers are an all-in one design using a combination of an 8-direction digital joystick and a 270-degree paddle, designed by John Amber. The 2800's case design departed from the 2600, using a wedge shape with non-protruding switches. The case style is the basis for the Atari 7800, which was redesigned for the 7800 by Barney Huang.

1986 model
The cost-reduced 1986 model, sometimes referred to as the "2600 Jr.", has a smaller form factor with an Atari 7800-like appearance. It was advertised as a budget gaming system (under US$50) with the ability to run a large collection of games. Released after the video game crash of 1983, and after the North American launch of the Nintendo Entertainment System, the 2600 was supported with new games and television commercials promoting "The fun is back!". Atari released several minor stylistic variations: the "large rainbow" (shown), "short rainbow", and an all-black version sold only in Ireland. Later European versions include a joypad.

Unreleased prototypes
The Atari 2700 was a version of the 2600 with wireless controllers.

The CX2000, with integrated joystick controllers, was a redesign based on human factor analysis by Henry Dreyfuss Associates.

The circa-1982 Atari 3200 was a backwards compatible 2600 successor with "more memory, higher resolution graphics and improved sound".

Related hardware
The Atari 7800, announced in 1984 and released in 1986, is the official successor to the Atari 2600 and is backward compatible with 2600 cartridges.

Multiple retro-style consoles and microconsoles have been released since the lifespan of the original Atari 2600:
 * The TV Boy includes 127 games in an enlarged joypad.
 * The Atari Classics 10-in-1 TV Game, manufactured by Jakks Pacific, emulates the 2600 with ten games inside a Atari-style joystick with composite-video output.
 * The Atari Flashback 2 (2005) contains 40 games, with four additional programs unlocked by a cheat code. It is compatible with original 2600 controllers and can be modified to play original 2600 cartridges.
 * In 2017, Hyperkin announced the RetroN 77, a clone of the Atari 2600 that plays original cartridges instead of preinstalled games.
 * The Atari VCS (2021 console) can download and emulate 2600 games via an online store.
 * Atari, Inc. released the Atari 2600+, an 80% scale replica of the 1980 CX2600-A model, on November 17, 2023. The 2600+ includes support for original Atari 2600 and 7800 cartridges.

Games
In 1977, nine games were released on cartridge to accompany the launch of the console: Air-Sea Battle, Basic Math, Blackjack, Combat, Indy 500, Star Ship, Street Racer, Surround, and Video Olympics. Indy 500 shipped with special "driving controllers", which are like paddles but rotate freely. Street Racer and Video Olympics use the standard paddle controllers. Atari, Inc. was the only developer for the first few years, releasing dozens of games.

Atari determined that box art featuring only descriptions of the game and screenshots would not be sufficient to sell games in retail stores, since most games were based on abstract principles and screenshots give little information. Atari outsourced box art to Cliff Spohn, who created visually interesting artwork with implications of dynamic movement intended to engage the player's imagination while staying true to the gameplay. Spohn's style became a standard for Atari when bringing in assistant artists, including Susan Jaekel, Rick Guidice, John Enright, and Steve Hendricks. Spohn and Hendricks were the largest contributors to the covers in the Atari 2600 library. Ralph McQuarrie, a concept artist on the Star Wars series, was commissioned for one cover, the arcade conversion of Vanguard. These artists generally conferred with the programmer to learn about the game before drawing the art.

An Atari VCS port of the Breakout arcade game appeared in 1978. The original is in black and white with a colored overlay, and the home version is in color. In 1980, Atari released Adventure, the first action-adventure game, and the first home game with a hidden Easter egg.

Rick Maurer's port of Taito's Space Invaders, released in 1980, is the first VCS game to have more than one million copies sold—eventually doubling that within a year and totaling more than 6 million cartridges by 1983. It became the killer app to drive console sales. Versions of Atari's own Asteroids and Missile Command arcade games, released in 1981, were also major hits.

Each early VCS game is in a 2K ROM. Later games, like Space Invaders, have 4K. The VCS port of Asteroids (1981) is the first game for the system to use 8K via a bank switching technique between two 4K segments. Some later releases, including Atari's ports of Dig Dug and Crystal Castles, are 16K cartridges. One of the final games, Fatal Run (1990), doubled this to 32K.

Many early VCS titles were able to display in both monochrome (black and white) and full color through the use of the "TV type" switch on the console. This allowed the VCS games to function on both monochrome and color televisions. However, beginning around the rebranding from "VCS" to "2600", support for black and white display modes diminished greatly, with most releases during this period only displaying in color and the TV type switch serving no function. Other later titles, such as Secret Quest, began using the TV type switch for gameplay functions, such as pausing.

Two Atari-published games, both from the system's peak in 1982, E.T. the Extra-Terrestrial and Pac-Man, are cited as factors in the video game crash of 1983.

A company named American Multiple Industries produced a number of pornographic games for the 2600 under the Mystique Presents Swedish Erotica label. The most notorious, Custer's Revenge, was protested by women's and Native American groups because it depicted General George Armstrong Custer raping a bound Native American woman. Atari sued American Multiple Industries in court over the release of the game.

Legacy

The 2600 was so successful in the late 1970s and early 1980s that "Atari" was a synonym for the console in mainstream media and for video games in general. Jay Miner directed the creation of the successors to the 2600's TIA chip—CTIA and ANTIC—which are central to the Atari 8-bit computers released in 1979 and later the Atari 5200 console.

The Atari 2600 was inducted into the National Toy Hall of Fame at The Strong in Rochester, New York, in 2007. In 2009, the Atari 2600 was named the number two console of all time by IGN, which cited its remarkable role behind both the first video game boom and the video game crash of 1983, and called it "the console that our entire industry is built upon".

In November 2021, the current incarnation of Atari announced three 2600 games to be published under "Atari XP" label: Yars' Return, Aquaventure, and Saboteur. These were previously included in Atari Flashback consoles.

title: Atari 2600


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Atari 5200

The Atari 5200 SuperSystem or simply Atari 5200 is a home video game console introduced in 1982 by Atari, Inc. as a higher-end complement for the popular Atari Video Computer System. The VCS was renamed to the Atari 2600 at the time of the 5200's launch. Created to compete with Mattel's Intellivision, the 5200 wound up a direct competitor of ColecoVision shortly after its release. While the Coleco system shipped with the first home version of Nintendo's Donkey Kong, the 5200 included the 1978 arcade game Super Breakout which had already appeared on the Atari 8-bit computers and Atari VCS in 1979 and 1981 respectively.

The CPU and the graphics and sound hardware are almost identical to that of the Atari 8-bit computers, although software is not directly compatible between the two systems. The 5200's controllers have an analog joystick and a numeric keypad along with start, pause, and reset buttons. The 360-degree non-centering joystick was touted as offering more control than the eight-way Atari CX40 joystick of the 2600, but was a focal point for criticism.

On May 21, 1984, during a press conference at which the Atari 7800 was introduced, company executives revealed that the 5200 had been discontinued after less than two years on the market. Total sales of the 5200 were reportedly in excess of 1 million units, far short of its predecessor's sales of over 30 million.

Hardware

Following the release of the Video Computer System in 1977, Atari began developing hardware for a next generation game console. Instead, it was used as the basis for the Atari 400 and 800 home computers.

Atari later decided to re-enter the console market using the same technology. Prototypes were called the "Atari Video System X – Advanced Video Computer System". Actual working Atari Video System X machines, whose hardware is 100% identical to the Atari 5200 do exist, but are extremely rare.

The initial 1982 release of the system had four controller ports, compared to two in most other consoles. The controllers have an analog joystick, numeric keypad, two fire buttons on each side of the controller, and game function keys for Start, Pause, and Reset. The 5200 also featured the innovation of the first automatic TV switchbox, allowing it to automatically switch from regular TV viewing to the game system signal when the system was activated. Previous RF adapters required the user to slide a switch on the adapter by hand. The RF box was also where the power supply connected in a unique dual power/television signal setup similar to the RCA Studio II's. A single cable coming out of the 5200 plugged into the switch box and carried both electricity and the television signal.

The 1983 revision of the Atari 5200 has two controller ports instead of four, and a change back to the more conventional separate power supply and standard non-autoswitching RF switch. It also has changes in the cartridge port address lines to allow for the Atari 2600 adapter released that year. While the adapter was only made to work on the two-port version, modifications can be made to the four-port to make it line-compatible. In fact, towards the end of the four-port model's production run, there were a limited number of consoles produced which included these modifications. These consoles can be identified by an asterisk in their serial numbers.

At one point following the 5200's release, Atari planned a smaller, cost-reduced version of the Atari 5200, which removed the controller storage bin. Code-named the "Atari 5100" (a.k.a. "Atari 5200 Jr."), only a few fully working prototype 5100s were made before the project was canceled.

Controllers

The controller prototypes used in the electrical development lab employed a yoke-and-gimbal mechanism that came from an RC airplane controller kit. The design of the analog joystick, which used a weak rubber boot rather than springs to provide centering, proved to be ungainly and unreliable. They quickly became the Achilles' heel of the system due to the combination of an overly complex mechanical design and a very low-cost internal flex circuit system. Another major flaw of the controllers was that the design did not translate into a linear acceleration from the center through the arc of the stick travel. The controllers did, however, include a pause button, a unique feature at the time. Various third-party replacement joysticks were also released, including those made by Wico.

Atari Inc. released the Pro-Line Trak-Ball controller, which is used for games such as Centipede and Missile Command. A paddle controller and an updated self-centering version of the original controller were also in development, but never made it to market.

Games were shipped with plastic card overlays that snapped in over the keypad. The card would indicate which game functions, such as changing the view or vehicle speed, were assigned to each key.

The primary controller was ranked the 10th worst video game controller by IGN editor Craig Harris. An editor for Next Generation said that their non-centering joysticks "rendered many games nearly unplayable".

Internal differences from 8-bit computers
David H. Ahl in 1983 described the Atari 5200 as "a 400 computer in disguise". Its internal design is similar to that of Atari 8-bit computers using the ANTIC, POKEY, and GTIA coprocessors. Software designed for one does not run on the other, but source code can be mechanically converted unless it uses computer-specific features. Antic magazine reported in 1984 that "the similarities grossly outweigh the differences, so that a 5200 program can be developed and almost entirely debugged [on an Atari 8-bit computer] before testing on a 5200". John J. Anderson of Creative Computing alluded to the incompatibility being intentional, caused by Atari's console division removing 8-bit compatibility to not lose control to the rival computer division.

Besides the 5200's lack of a keyboard, the differences are:
 * The Atari computer 10 KB operating system is replaced with a simpler 2 KB version, of which 1 KB is the built-in character set.
 * Some hardware registers, such as those of the GTIA and POKEY chips, are at different memory locations.
 * The purpose of some registers is slightly different on the 5200.
 * The 5200's analog joysticks appear as pairs of paddles to the hardware, which requires different input handling from the digital joystick input on the Atari computers

In 1987, Atari Corporation released the XE Game System console, which is a repackaged 65XE (from 1985) with a detachable keyboard that can run home computer titles directly, unlike the 5200. Anderson wrote in 1984 that Atari could have released a console compatible with computer software in 1981.

Reception
The Atari 5200 did not fare well commercially compared to its predecessor, the Atari 2600. While it touted superior graphics to the 2600 and Mattel's Intellivision, the system was initially incompatible with the 2600's expansive library of games, and some market analysts have speculated that this hurt its sales, especially since an Atari 2600 cartridge adapter had been released for the Intellivision II. (A revised two-port model was released in 1983, along with a game adapter that allowed gamers to play all 2600 games.) This lack of new games was due in part to a lack of funding, with Atari continuing to develop most of its games for the saturated 2600 market.

Many of the 5200's games appeared simply as updated versions of 2600 titles, which failed to excite consumers. Its pack-in game, Super Breakout, was criticized for not doing enough to demonstrate the system's capabilities. This gave the ColecoVision a significant advantage as its pack-in, Donkey Kong, delivered a more authentic arcade experience than any previous game cartridge. In its list of the top 25 game consoles of all time, IGN claimed that the main reason for the 5200's market failure was the technological superiority of its competitor, while other sources maintain that the two consoles are roughly equivalent in power.

The 5200 received much criticism for the "sloppy" design of its non-centering analog controllers. Anderson described the controllers as "absolutely atrocious".

David H. Ahl of Creative Computing Video & Arcade Games said in 1983 that the "Atari 5200 is, dare I say it, Atari's answer to Intellivision, Colecovision, and the Astrocade", describing the console as a "true mass market" version of the Atari 8-bit computers despite the software incompatibility. He criticized the joystick's imprecise control but said that "it is at least as good as many other controllers", and wondered why Super Breakout was the pack-in game when it did not use the 5200's improved graphics.

Technical specifications

 * CPU: Custom MOS Technology 6502C @ 1.79 MHz (not a 65C02)
 * Graphics chips: ANTIC and GTIA
 * Support hardware: 3 custom VLSI chips
 * Screen resolution: 14 modes: Six text modes (8×8, 4×8, and 8×10 character matrices supported), Eight graphics modes including 80 pixels per line (16 color), 160 pixels per line (4 color), 320 pixels per line (2 color), variable height and width up to overscan 384×240 pixels
 * Color palette: 128 (16 hues, 8 luma) or 256 (16 hues, 16 luma)
 * Colors on screen: 2 (320 pixels per line) to 16 (80 pixels per line). Up to 23 colors per line with player/missile and playfield priority control mixing. Register values can be changed at every scanline using ANTIC display list interrupts, allowing up to 256 (16 hues, 16 luma) to be displayed at once, with up to 16 per scanline.
 * Sprites: Four 8-pixel-wide sprites, four 2-pixel-wide sprites; height of each is either 128 or 256 pixels; 1 color per sprite
 * Scrolling: Coarse and fine scrolling horizontally and vertically. (Horizontal coarse scroll 4, 8, or 16-pixel/color clock increments, and vertically by mode line height 2, 4, 8, or 16 scan lines.) (Or horizontal fine scroll 0 to 3, 7, or 15 single-pixel/color clock increments and then a 4, 8, or 16-pixel/color clock increment coarse scroll; and vertical fine scroll 0 to 1, 3, 7, or 15 scan line increments and then a 2, 4, 8, or 16 scan line increment coarse scroll)
 * Sound: 4-channel PSG sound via POKEY sound chip, which also handles keyboard scanning, serial I/O, high resolution interrupt capable timers (single cycle accurate), and random number generation.
 * RAM: 16 KB
 * ROM:
 * 2 KB on-board BIOS for system startup and interrupt routing.
 * 32 KB ROM window for standard game cartridges, expandable using bank switching techniques.
 * Dimensions: 13" × 15" × 4.25"

Popular culture
Critical to the plot of the 1984 film Cloak & Dagger is an Atari 5200 game cartridge called Cloak & Dagger. The arcade version appears in the movie; in actuality the Atari 5200 version was started but never completed. The game was under development with the title Agent X when the movie producers and Atari learned of each other's projects and decided to cooperate. This collaboration was part of a larger phenomenon, of films featuring video games as critical plot elements (as with Tron and The Last Starfighter) and of video game tie-ins to the same films (as with the Tron games for the Intellivision and other platforms).

title: Atari 5200


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Atari 7800

The Atari 7800 ProSystem, or simply the Atari 7800, is a home video game console officially released by Atari Corporation in 1986 as the successor to both the Atari 2600 and Atari 5200. It can run almost all Atari 2600 cartridges, making it one of the first consoles with backward compatibility. It shipped with a different model of joystick from the 2600-standard CX40 and Pole Position II as the pack-in game. Most of the announced titles at launch were ports of 1981–1983 arcade video games.

Designed by General Computer Corporation, the 7800 has significantly improved graphics hardware over Atari's previous consoles, but the same Television Interface Adaptor chip that launched with the 2600 in 1977 is used to generate audio. In an effort to prevent the flood of poor quality games that contributed to the video game crash of 1983, cartridges had to be digitally signed by Atari.

The Atari 7800 was first announced by Atari, Inc. on May 21, 1984, but a general release was shelved until May 1986 due to the sale of the company. Atari Corporation dropped support for the 7800, along with the 2600 and the Atari 8-bit computers, on January 1, 1992.

History
Atari had been facing pressure from Mattel and Coleco with their Intellivision and ColecoVision consoles respectively, which supported graphics that more closely mirrored arcade games of the time than either the Atari 2600 or 5200. The Atari 5200 (released as a successor to the Atari 2600) aimed to address this issue, but was ultimately criticized for lack of backward compatibility with 2600 games, flawed controllers, and initially high price. Released just prior to the video game crash of 1983, the 5200 failed to meet sales expectations.

The Atari 7800 ProSystem was the first console from Atari, Inc. designed by an outside company, General Computer Corporation. It was designed in 1983–84 with an intended mass market rollout in June 1984, but was canceled after the sale of the company to Tramel Technology Ltd on July 2, 1984. The project was originally called the Atari 3600.

With a background in creating arcade games such as Food Fight, GCC designed the new system with a graphics architecture similar to arcade machines of the time. The CPU is a slightly customized 6502 processor, the Atari SALLY, running at 1.79 MHz. By some measures the 7800 is more powerful, and by others less, than the 1983 Nintendo Entertainment System. It uses the 2600's Television Interface Adaptor chip, with the same restrictions, for generating two-channels of audio.

Launch
The 7800 was announced on May 21, 1984. Thirteen games were announced for the system's launch: Ms. Pac-Man, Pole Position II, Centipede, Joust, Dig Dug, Nile Flyer (eventually released as Desert Falcon), Robotron: 2084, Galaga, Food Fight, Ballblazer, Rescue on Fractalus! (later canceled), Track & Field, and Xevious.

On July 2, 1984, Warner Communications sold Atari's Consumer Division to Jack Tramiel. All projects were halted during an initial evaluation period. GCC had not been paid for their development of the 7800, and Warner and Tramiel fought over who was accountable. In May 1985, Tramiel relented and paid GCC. This led to additional negotiations regarding the launch titles GCC had developed, then an effort to find someone to lead their new video game division, which was completed in November 1985. The original production run of the Atari 7800 languished in warehouses until it was introduced in January 1986.

The console was released nationwide in May 1986 for $79.95. It launched with titles intended for the 7800's debut in 1984 and was aided by a marketing campaign with a budget in the "low millions" according to Atari Corporation officials. This was substantially less than the $9 million spent by Sega and the $16 million spent by Nintendo. The keyboard and high score cartridge planned by Warner were cancelled. The 7800 addressed many of the most common complaints with the preceding 5200, including a smaller size, built-in backward compatibility, and an improved controller design.

In February 1987, Computer Entertainer reported that 100,000 Atari 7800 consoles had been sold in the United States, including those which had been warehoused since 1984. This was less than the Master System's 125,000 and the NES's 1.1 million. A complaint from owners in 1986 was the slow release of games. Galaga in August was followed by Xevious in November. By the end of 1986, the 7800 had 10 games, compared to Sega's 20 and Nintendo's 36. Atari would sell over 1 million 7800 consoles by June 1988.

Discontinuation
On January 1, 1992, Atari Corporation announced the end of production and support for the 7800, 2600, and the 8-bit computer family including the Atari XEGS. At least one game, an unreleased port of Toki, was worked on past this date. By the time of the discontinuation, the Nintendo Entertainment System controlled 80% of the North American market while Atari had 12%. In Europe, last stocks of the 7800 were sold until summer/fall of 1995.

Retro Gamer magazine issue 132 reported that according to Atari UK Marketing Manager Darryl Still, "it was very well stocked by European retail; although it never got the consumer traction that the 2600 did, I remember we used to sell a lot of units through mail order catalogues and in the less affluent areas".

Technical specifications

 * CPU: Atari SALLY (custom variant of the 6502)
 * 1.79 MHz, which drops to 1.19 MHz when the Television Interface Adaptor or (6532 RAM-I/O-Timer) chips are accessed
 * Unlike a standard 6502, SALLY can be halted in a known state with a single pin to let other devices control the bus.
 * Sometimes referred to by Atari as "6502C", but not the same as the official MOS Technology 6502C.
 * RAM: 4 KB (2 6116 2Kx8 RAM ICs)
 * ROM: built in 4 KB BIOS ROM, 48 KB Cartridge ROM space without bank switching
 * Graphics: MARIA custom chip
 * Resolution: 160×240 (160×288 PAL) or 320×240 (320×288 PAL)
 * Color palette: 256 (16 hues * 16 luma), different graphics modes restricted the number of usable colors and the number of colors per sprite
 * Direct Memory Access (DMA)
 * Graphics clock: 7.15 MHz
 * Line buffer: 200 bytes (double buffering), 160 sprite pixels per scanline, up to 30 sprites per scanline (without background), up to 100 sprites on screen
 * Sprite/zone sizes: 4 to 160 width, height of 4, 8 or 16 pixels
 * Colors per sprite: 1 to 12 (1 to 8 visible colors, 1 to 4 transparency bits)
 * I/O: Joystick and console switch IO handled by 6532 RIOT and TIA
 * Ports
 * 2 joystick ports
 * cartridge port
 * expansion connector
 * power in
 * RF output
 * Sound: TIA as used in the 2600 for video and sound. In 7800 mode it is only used for sound.
 * At least two games include a POKEY sound chip for improved audio.

Graphics
Graphics are generated by the custom MARIA chip, which uses an approach common in contemporary arcade system boards and is different from other second and third generation consoles. Instead of a limited number of hardware sprites, MARIA treats everything as a sprite described in a series of display lists. Each display list contains pointers to graphics data and color and positioning information.

MARIA supports a palette of 256 colors and graphics modes which are either 160 pixels wide or 320 pixels wide. While the 320 pixel modes theoretically enable the 7800 to create games at higher resolution than the 256 pixel wide graphics found in the Nintendo Entertainment System and Master System, the processing demands of MARIA result in most games using the 160 pixel mode.

Each sprite can have from 1 to 12 colors, with 3 colors plus transparency being the most common. In this format, the sprite references one of 8 palettes, where each palette holds 3 colors. The background (visible when not covered by other objects) can also be assigned a color. In total, 25 colors can appear on a scan line.

The graphics resolution, color palettes, and background color can be adjusted between scan lines. This can be used to render high resolution text in one area of the screen, while displaying more colorful graphics at lower resolution in the gameplay area.

Sound
The 7800 uses the TIA chip for two channel audio, the same chip used in the 1977 Atari VCS, and the sound is of the same quality as that system. To compensate, GCC's engineers allowed games to include a POKEY audio chip in the cartridge. Only Ballblazer and Commando do this.

GCC planned to make a low-cost, high performance sound chip, GUMBY, which could also be placed in 7800 cartridges to enhance its sound capabilities further. This project was cancelled when Atari was sold to Jack Tramiel.

Digitally signed cartridges
Following the large number of low quality, third party games for the Atari 2600, Atari required that cartridges for the 7800 be digitally signed. When a cartridge is inserted into the system, the BIOS generates a signature of the cartridge ROM and compares it to the one stored on the cartridge. If they match, the console operates in 7800 mode, granting the game access to MARIA and other features, otherwise the console operates as a 2600. This digital signature code is not present in PAL 7800s, which use various heuristics to detect 2600 cartridges, due to export restrictions.

Backward compatibility
The 7800's compatibility with the Atari 2600 is made possible by including many of the same chips used in the 2600. When playing an Atari 2600 game, the 7800 uses a Television Interface Adaptor chip to generate graphics and sound. The processor is slowed to 1.19 MHz, to mirror the performance of the 2600's 6507 chip. RAM is limited to 128 bytes and cartridge data is accessed in 4K blocks.

When in 7800 mode (signified by the appearance of the full-screen Atari logo), the graphics are generated entirely by the MARIA graphics processing unit. All system RAM is available and cartridge data is accessed in larger 48K blocks. The system's SALLY 6502 runs at its normal 1.79 MHz. The 2600 chips are used to generate sound and to provide the interfaces to the controllers and console switches.

System revisions

 * Initial version: two joystick ports on lower front panel. Side expansion port for upgrades and add-ons. Bundled with two CX24 Pro-Line joysticks, AC adapter, switchbox, RCA connecting cable, and Pole Position II cartridge.
 * Second revision: Slightly revised motherboard. Expansion port connector removed from motherboard but is still etched. Shell has indentation of where expansion port was to be.
 * Third revision: Same as above but with only a small blemish on the shell where the expansion port was.

Peripherals

The Atari 7800 came bundled with the Atari Pro-Line Joystick, a two-button controller with a joystick for movement. The Pro-Line was developed for the 2600 and advertised in 1983, but delayed until Atari proceeded with the 7800. The right fire button only works as a separate fire button for certain 7800 games; otherwise, it duplicates the left fire button, allowing either button to be used for 2600 games. While physically compatible, the 7800's controllers do not work with the Sega Master System, and Sega's controllers are unable to use the 7800's two-button mode.

In response to criticism over ergonomic issues with the Pro-Line controllers, Atari later released a joypad controller with the European 7800. Similar in style to controllers found on Nintendo and Sega systems, it was not available in the United States.

The Atari XG-1 light gun, bundled with the Atari XEGS and also sold separately, is compatible with the 7800. Atari released five 7800 light gun games: Alien Brigade, Barnyard Blaster, Crossbow, Meltdown, and Sentinel.

Cancelled peripherals
After the acquisition of the Atari Consumer Division by Jack Tramiel in 1984, several expansion options for the system were cancelled:

 * The High Score Cartridge was designed to save high scores for up to 65 separate games. The cartridge was intended as a pass-through device, similar to the later Game Genie. Nine games were programmed to support the cartridge.
 * The expansion port, to allow for the addition of a planned computer keyboard and connection to laserdisc players and other peripherals, was removed in the second and third revisions of the 7800.
 * A dual joystick holder was designed for Robotron: 2084 and future games like Battlezone, but not produced.

Games

While the system can play the over 400 games for the Atari 2600, there were only 59 official releases for the 7800. The lineup emphasized high-quality versions of games from the golden age of arcade video games. Pole Position II, Dig Dug, and Galaga, by the time of the 1986 launch, were three, four, and five years old, respectively. A raster graphics version of 1979's Asteroids was released in 1987. In 1988, Atari published a conversion of Nintendo's Donkey Kong, seven years after the original arcade game and five years after the Atari 8-bit computer cartridge. Atari also marketed a line of games called "Super Games" which were arcade and computer games previously not playable on a home console such as One-On-One Basketball and Impossible Mission.

Eleven games were developed and sold by three third-party companies under their own labels (Absolute Entertainment, Activision, and Froggo) with the rest published by Atari Corporation. Most of the games from Atari were developed by outside companies under contract.

Some NES games were developed by companies who had licensed their title from a different arcade manufacturer. While the creator of the NES version would be restricted from making a competitive version of an NES game, the original arcade copyright holder was not precluded from licensing out rights for a home version of an arcade game to multiple systems. Through this loophole, Atari 7800 conversions of Mario Bros., Double Dragon, Commando, Rampage, Xenophobe, Ikari Warriors, and Kung-Fu Master were licensed and developed.

A final batch of games was released by Atari in 1990: Alien Brigade, Basketbrawl, Fatal Run, Meltdown, Midnight Mutants, MotorPsycho, Ninja Golf, Planet Smashers, and Scrapyard Dog. Scrapyard Dog was later released for the Atari Lynx.

Atari Flashback
In 2004, the Infogrames-owned version of Atari released the Atari Flashback console. It resembles a miniature Atari 7800 and has five 7800 and fifteen 2600 games built-in. Built using the NES-On-A-Chip hardware instead of recreating the Atari 7800 hardware, it was criticized for failing to properly replicate the actual gaming experience. A subsequent 7800 project was cancelled after prototypes were made.

Game development
The digital signature long prevented aftermarket games from being developed. The signing software was eventually found and released at Classic Gaming Expo in 2001. Several new Atari 7800 games such as Beef Drop, B*nQ, Combat 1990, CrazyBrix, Failsafe, and Santa Simon have been released..

Source code
In July 2009 the source code to 13 games, as well as the OS and development tools for the Atari ST system, were released. Commented assembly language source code was made available for Centipede, Commando, Crossbow, Desert Falcon, Dig Dug, Food Fight, Galaga, Hat Trick, Joust, Ms. Pac-Man, Super Stunt Cycle, Robotron: 2084, and Xevious.

title: Atari 7800