The Amiga 500 known as the A500, is the first low-end Commodore Amiga 16/32-bit multimedia home/personal computer. It was announced at the winter Consumer Electronics Show in January 1987 – at the same time as the high-end Amiga 2000 – and competed directly against the Atari 520ST. Before Amiga 500 was shipped, Commodore suggested that the list price of the Amiga 500 was US$595.95 without a monitor. At delivery in October 1987, Commodore announced that the Amiga 500 would carry a US$699/£499 list price. In Europe, the Amiga 500 was released in May 1987. In the Netherlands, the A500 was available from April 1987 for a list price of 1499 HFL; the Amiga 500 represents a return to Commodore's roots by being sold in the same mass retail outlets as the Commodore 64 – to which it was a spiritual successor – as opposed to the computer-store-only Amiga 1000, as well as being another computer whose keyboard is included in the same case. The original Amiga 500 proved to be Commodore's best-selling Amiga model, enjoying particular success in Europe.
Although popular with hobbyists, arguably its most widespread use was as a gaming machine, where its advanced graphics and sound were of significant benefit. It has been claimed that over 6 million A500s were sold worldwide, according to Commodore UK, the entire sales of all Amigas in both Europe and the USA were 4-5 million. While not the first computer to have an open architecture, the Amiga is considered due to its expandability as one of the early examples. In October 1989, the Amiga 500 dropped its price from £499 to £399 and was bundled with the Batman Pack in the United Kingdom which included the games Batman, F/A-18 Interceptor, The New Zealand Story and the bitmap graphics editor, Deluxe Paint 2. Included was the Commodore A520 RF Modulator, an adaptor which allowed the A500 to be used with a conventional CRT television set, via its RF antenna socket. In late 1991, an enhanced model known as the Amiga 500 Plus replaced the original 500 in some markets; the Amiga 500 series was discontinued in June 1992 and replaced by the specified and priced Amiga 600, although this new machine had been intended as a much cheaper model, which would have been the A300.
In late 1992, Commodore released the "next-generation" Amiga 1200, a machine closer in concept to the original Amiga 500, but featuring significant technical improvements. Despite this, neither the A1200 nor the A600 replicated the commercial success of its predecessor, as by this time, the popular market was definitively shifting from the home computer platforms of the past to commodity Wintel PCs and the new "low-cost" Macintosh Classic, LC and IIsi models. Outwardly resembling the Commodore 128 and codenamed "Rock Lobster" during development, the Amiga 500 houses the keyboard and CPU in one shell, unlike the Amiga 1000, it utilizes a Motorola 68000 microprocessor running at 7.09379 MHz. The CPU implements a 32-bit model, has 32-bit registers and 32-bit internal data bus, but it has a 16-bit main ALU, uses a 16-bit external data bus and 24-bit address bus, providing a maximum of 16 MB of address space; the earliest Amiga 500 models use nearly the same Original Amiga chipset as the Amiga 1000.
So graphics can be displayed in multiple resolutions and color depths on the same screen. Resolutions vary from 320×200 to 640×400 for NTSC and 320×256 to 640×512 for PAL The system uses planar graphics, with up to five bitplanes allowing 2-, 4-, 8-, 16-, 32-color screens, from a palette of 4096 colors. Two special graphics modes are available: Extra HalfBrite, which uses a 6th bitplane as a mask to cut the brightness of any pixel in half, Hold And Modify which allows all 4096 colors to be used on screen simultaneously. Revisions of the chipset are PAL/NTSC switchable in software; the sound chip produces four hardware-mixed channels, two to the left and two to the right, of 8-bit PCM at a sampling frequency of up to 28 kHz. Each hardware channel has its own independent volume level and sampling rate, can be designated to another channel where it can modulate both volume and frequency using its own output. With DMA disabled it's possible to output with a sampling frequency up to 56 kHz. There's a common trick to output sound with 14-bit precision that can be combined to output 14-bit 56 kHz sound.
The stock system comes with AmigaOS version 1.2 or 1.3 and 512 KiB of chip RAM, one built-in double-density standard floppy disk drive, programmable and can read 720 KiB IBM PC disks, 880 KiB standard Amiga disks, up to 984 KiB using custom-formatting drivers. Despite the lack of Amiga 2000-compatible internal expansion slots, there are many ports and expansion options. There are two DE9M Atari joystick ports for stereo audio. There is a floppy drive port for daisy-chaining up to three extra floppy disk drives via an DB23F connector; the then-standard RS-232 serial port and Centronics parallel port are included. The power supply is; the system displays video in analog RGB 50 Hz PAL or 60 Hz NTSC through a proprietary DB23M connector and in NTSC mode the line frequency is 15,750 Hz HSync for standard video modes, compatible with NTSC television and CVBS/RGB video, but out of range for most VGA-compatible monitors, while a multisync monitor is required for some of the higher resolutions. This connection can also
The Commodore Plus/4 is a home computer released by Commodore International in 1984. The "Plus/4" name refers to the four-application ROM resident office suite. Internally, the Plus/4 shared the same basic architecture as the lower-end Commodore 16 and 116 models, was able to use software and peripherals designed for them; the Plus/4 was incompatible with some of its hardware. Although the Commodore 64 was more established than the Plus/4 it was aimed at the more business orientated part of the personal computer market. While the Plus/4 had some success in Europe, it was a failure in the United States, where it was derided as the "Minus/60". In the early 1980s, Commodore found. Companies like Texas Instruments and Timex Corporation were releasing computers that undercut the price of Commodore's PET line. Commodore's MOS Technology division had designed a video chip but could not find any third-party buyers; the VIC-20 resulted from the confluence of these events and it was introduced in 1980 at a list price of $299.95.
Spurred by the competition, Commodore was able to reduce the VIC's street price to $99, it became the first computer to sell over 1 million units. The Commodore 64, the first 64-KB computer to sell for under US$600 in the USA, was another salvo in the price war but it was far more expensive to make than the VIC-20 because it used discrete chips for video, I/O. Still, the C64 went on to become a best-seller and was selling for $199 at the time of the Plus/4's introduction. While C64 sales were rising, Commodore president Jack Tramiel wanted a new computer line that would use fewer chips and at the same time address some of the user complaints about the VIC and C64. Rumors spread in late 1983 of a new computer in 1984 called the "Commodore 444" or "Ted", with built-in word processing and spreadsheet software, that it would be one of four new computers that would replace the VIC-20 and 64, which the company would discontinue; the company's third salvo – which, as it turned out, was fired just as most of Commodore's competition was leaving the home computer market – was the C116, C16, 264, which became the Plus/4.
There were prototypes of a 232 a 32 KB version of the Plus/4 without the software ROMs, a V364 which had a numeric keypad and built-in voice synthesis. The latter two models never made it to production. All these computers used a 6502 compatible MOS 7501 or 8501, clocked 75% faster than the CPUs used in the VIC-20 and C64, a MOS Technology TED all-in-one video, I/O chip; the Plus/4's design is thus philosophically closer to that of the VIC-20 than that of the C64. The Plus/4 was the flagship computer of the line; the Plus/4 had 64 KB of memory while the C16 and 116 had 16 KB. The Plus/4 had built-in software; the Plus/4 and C16 had full-travel keyboards. The C116 was only sold in Europe. All of the machines were distinguished by light gray keys; this was a reversal of the color scheme on the 64 and VIC, which used lighter cases and darker-colored keys. The Plus/4 was introduced in June 1984 and priced at US$299, it was discontinued in 1985. Commodore's intent with the Plus/4 was not to replace the C64, but to expand the home computer market and sell the Plus/4 to users who were more interested in serious applications than in gaming.
By 1984, however, in the USA, most of these customers were beginning to switch to the new, low-cost IBM PC compatibles such as the Leading Edge Model D and Tandy 1000 series. Although, like the Commodore B128, Plus/4 systems remained available from liquidators for years after its discontinuation, the Plus/4 disappeared from Commodore's major markets by 1988; the Plus/4 was used in Denmark, as part of a bundled product from the then-national telecompany to help hearing-impaired people communicate over telephone lines. Outgoing calls were made from the Plus/4 via modem to a call center where a service assistant would read the written input from the user, call the other party and read the text aloud. Vice versa, incoming calls could be made from other users to the call center, who would dial the Plus/4 modem. A strobe light connected to the Plus/4 would notify the hearing impaired about the incoming call; the Plus/4 enjoyed lasting popularity in Hungary due to CBM's decision to saturate the Central European market with the failed product at a reduced price.
A number of unofficial ports of C64 games were produced by Hungarian users. The TED offered 121-color video, a palette matched only by Atari's 8-bit computer line at the time, 320×200 video resolution, similar to many computers intended to be capable of connecting to a television; the Plus/4's memory map, which used bank switching far more extensively than the C64, gave it a 56% larger amount of user-accessible memory than the C64 for programming in BASIC, its BASIC programming language was vastly improved, adding sound and graphics commands as well as looping commands that improved program structure. Commodore released a high-speed floppy disk drive for the Plus/4, the Commodore 1551, which offered much better performance than the C64/1541 combination because it used a parallel interface rather than a serial bus; the 1551 plugged into the cartridge port. The TED chip had identical resolutions and video modes to the VIC-II (bitmap or character graphics which could be hi
The Amiga 1200, or A1200, is Commodore International's third-generation Amiga computer, aimed at the home computer market. It was launched on October 21, 1992, at a base price of £399 in the United Kingdom and $599 in the United States; the A1200 was launched a few months after the Amiga 600 using a similar, slimline design that replaced the earlier Amiga 500 Plus and Amiga 500. Whereas the A600 used the 16-bit Motorola 68000 of earlier Amigas, the A1200 was built around a faster, more powerful variant of the Motorola 68020. Physically the A1200 is an all-in-one design incorporating the CPU, disk drives in one physical unit; the A1200 has a similar hardware architecture to Commodore's Amiga CD32 game console. Only 30,000 A1200s were available at the UK launch. During the first year of its life the system sold well, but Commodore ran into cash flow problems and filed for bankruptcy. Worldwide sales figures for the A1200 are unknown, but 95,000 systems were sold in Germany before Commodore's bankruptcy.
After Commodore's demise in 1994, the A1200 disappeared from the market but was relaunched by Escom in 1995. The new Escom A1200 was priced at £399, it came bundled with two games, seven applications and AmigaOS 3.1. It was criticized for being priced 150 pounds higher than the Commodore variant, sold for two years prior, it came with a modified PC floppy disk drive, incompatible with some Amiga software. The A1200 was discontinued in 1996 as the parent company folded; the A1200 offers a number of advantages over earlier lower-budget Amiga models. It is a 32-bit design; the AGA chipset used in the A1200 is a significant improvement. AGA increases the color palette from 4096 colors to 16.8 million colors with up to 256 on-screen colors and an improved HAM mode allowing 262,144 on-screen colors. The graphics hardware features improved sprite capacity and faster graphics performance due to faster video memory. Additionally, compared to the A600 the A1200 offers greater expansion possibilities. Although it is a significant upgrade, the A1200 did not sell as well as the 500 and proved to be Commodore's last lower-budget model before filing for bankruptcy in 1994.
This is because the 1200 failed to repeat the technological advantage over competitors like the first Amiga systems. The AGA chipset was something of a disappointment. Commodore had been working on a much-improved version of the original Amiga chipset, codenamed "AAA", but when development fell behind they rushed out the less-improved AGA, found on the A4000 and CD32 units. While AGA is not notably less capable than its competition, when compared to VGA and its emerging extensions, the Amiga no longer commanded the lead it had in earlier times. Additionally, the Amiga's custom chips cost more to produce than the ubiquitous commodity chips utilized in PCs, making the A1200 more expensive; some industry commentators felt that the 68020 microprocessor was too outdated and that the new system should have been fitted with a 68030 to be competitive. Another issue was that the A1200 never supported high-density floppy disks without a special external drive or unreliable hacks, despite the PC HD drive in Escom models.
The gaming market, a major factor in the A500's popularity, was becoming more competitive with the emergence of more advanced and less expensive fourth generation console gaming systems, multimedia-enabled IBM PC compatibles. As a result, fewer retailers carried the A1200 in North America; the A1200 received bad press for being incompatible with a number of Amiga 500 games. Further criticism was directed at the A1200's power supply, inadequate in expanded systems, limiting upgrade options, popular with earlier Amiga models. Due to fewer sales and short lifetime, not as many games were produced for the A1200 than for the previous generations of Amiga computers; the Amiga 1200 was developed and released during the waning days of the home computer market its manufacturer once dominated. While Commodore never released any official sales figures, Commodore Frankfurt gave a figure of 95,000 Amiga 1200 systems sold in Germany. Worldwide sales of the A1200 would have been less than 1 million units; the A1200 has a Motorola 68EC020 CPU.
It is noteworthy that, like the 68000, the 68EC020 has a 24-bit address space, allowing for a theoretical maximum of 16 MB of memory. A stock A1200 has 2 MB of in-built "chip RAM".. Up to 8 MB of "fast RAM" can be added in the "trap-door" expansion slot, which doubles the speed of a stock machine. Various CPU upgrades featuring 68020, 68030, 68040, 68060 and PowerPC processors were made available by third-party developers; such upgrades utilize faster and greater capacity memory. The A1200 shipped with Commodore's third-generation Amiga chipset, the Advanced Graphics Architecture, which features improved graphical abilities in comparison to the earlier generations. However, the sound hardware remains identical to the design used in the Amiga 1000, though the AGA chipset allows higher sampling rates for sound playback, either by using a video mode with higher horizontal scan rate or by using the CPU to drive audio output directly. Like earlier models, the A1200 features several Amiga-specific connectors including two DE9M ports for joysticks and light pens, a standard 25-pin RS-232 serial port and a 25-pin Centronics parallel p
An operating system is system software that manages computer hardware and software resources and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may include accounting software for cost allocation of processor time, mass storage and other resources. For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is executed directly by the hardware and makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computer – from cellular phones and video game consoles to web servers and supercomputers; the dominant desktop operating system is Microsoft Windows with a market share of around 82.74%. MacOS by Apple Inc. is in second place, the varieties of Linux are collectively in third place. In the mobile sector, use in 2017 is up to 70% of Google's Android and according to third quarter 2016 data, Android on smartphones is dominant with 87.5 percent and a growth rate 10.3 percent per year, followed by Apple's iOS with 12.1 percent and a per year decrease in market share of 5.2 percent, while other operating systems amount to just 0.3 percent.
Linux distributions are dominant in supercomputing sectors. Other specialized classes of operating systems, such as embedded and real-time systems, exist for many applications. A single-tasking system can only run one program at a time, while a multi-tasking operating system allows more than one program to be running in concurrency; this is achieved by time-sharing, where the available processor time is divided between multiple processes. These processes are each interrupted in time slices by a task-scheduling subsystem of the operating system. Multi-tasking may be characterized in co-operative types. In preemptive multitasking, the operating system slices the CPU time and dedicates a slot to each of the programs. Unix-like operating systems, such as Solaris and Linux—as well as non-Unix-like, such as AmigaOS—support preemptive multitasking. Cooperative multitasking is achieved by relying on each process to provide time to the other processes in a defined manner. 16-bit versions of Microsoft Windows used cooperative multi-tasking.
32-bit versions of both Windows NT and Win9x, used preemptive multi-tasking. Single-user operating systems have no facilities to distinguish users, but may allow multiple programs to run in tandem. A multi-user operating system extends the basic concept of multi-tasking with facilities that identify processes and resources, such as disk space, belonging to multiple users, the system permits multiple users to interact with the system at the same time. Time-sharing operating systems schedule tasks for efficient use of the system and may include accounting software for cost allocation of processor time, mass storage and other resources to multiple users. A distributed operating system manages a group of distinct computers and makes them appear to be a single computer; the development of networked computers that could be linked and communicate with each other gave rise to distributed computing. Distributed computations are carried out on more than one machine; when computers in a group work in cooperation, they form a distributed system.
In an OS, distributed and cloud computing context, templating refers to creating a single virtual machine image as a guest operating system saving it as a tool for multiple running virtual machines. The technique is used both in virtualization and cloud computing management, is common in large server warehouses. Embedded operating systems are designed to be used in embedded computer systems, they are designed to operate on small machines like PDAs with less autonomy. They are able to operate with a limited number of resources, they are compact and efficient by design. Windows CE and Minix 3 are some examples of embedded operating systems. A real-time operating system is an operating system that guarantees to process events or data by a specific moment in time. A real-time operating system may be single- or multi-tasking, but when multitasking, it uses specialized scheduling algorithms so that a deterministic nature of behavior is achieved. An event-driven system switches between tasks based on their priorities or external events while time-sharing operating systems switch tasks based on clock interrupts.
A library operating system is one in which the services that a typical operating system provides, such as networking, are provided in the form of libraries and composed with the application and configuration code to construct a unikernel: a specialized, single address space, machine image that can be deployed to cloud or embedded environments. Early computers were built to perform a series of single tasks, like a calculator. Basic operating system features were developed in the 1950s, such as resident monitor functions that could automatically run different programs in succession to speed up processing. Operating systems did not exist in their more complex forms until the early 1960s. Hardware features were added, that enabled use of runtime libraries and parallel processing; when personal computers became popular in the 1980s, operating systems were made for them similar in concept to those used on larger computers. In the 1940s, the earliest electronic digital systems had no operating systems.
Electronic systems of this time were programmed on rows of mechanical switches or by jumper wires on plug boards. These were special-purpose systems that, for example, generated ballistics tables for the military or controlled the pri
The Commodore 16 is a home computer made by Commodore International with a 6502-compatible 7501 or 8501 CPU, released in 1984 and intended to be an entry-level computer to replace the VIC-20. A cost-reduced version, the Commodore 116, was sold only in Europe; the C16 and C116 belong to the same family as the higher-end Plus/4 and are internally similar to it. As a result, software is compatible among all three provided it can fit within the C16's smaller RAM and does not utilize the user port on the Plus/4. While the C16 was a failure on the US market, it enjoyed some success in certain European countries and in Mexico; the C16 was intended to compete with other sub-$100 computers from Timex Corporation and Texas Instruments. Timex's and Mattel's computers were less expensive than the VIC-20, although the VIC-20 offered better expandability, a full-travel keyboard, in some cases more memory, the C16 offered a chance to improve upon those advantages; the TI-99/4A was priced in-between Commodore's VIC-20 and Commodore 64, is somewhat between them in capability, but TI was lowering its prices.
On paper, the C16 is a closer match for the TI-99/4A than the aging VIC-20. Commodore president Jack Tramiel feared that one or more Japanese companies would introduce a consumer-oriented computer and undercut everyone's prices. Although the Japanese would soon dominate the U. S. video game console market, their feared dominance of the home computer field never materialized. Additionally, Mattel, TI departed the computer market before the C16 was released. Outwardly the C16 with a dark-gray case and light-gray keys; the keyboard layout differs from the earlier models, adding an escape key and four cursor keys replacing the shifted-key arrangement the C-64 and VIC inherited from the PET series. Performance-wise located between the VIC-20 and 64, it has 16 kilobytes of RAM with 12 KB available to its built-in BASIC interpreter, a new sound and video chipset offering a palette of 121 colors, the TED; the ROM resident BASIC 3.5, however, is more powerful than the VIC-20's and C64's BASIC 2.0, in that it has commands for sound and bitmapped graphics, as well as simple program tracing/debugging.
From a practical user's point of view, three tangible features the C16 lacks are a modem port and VIC-20/C64-compatible Datasette and game ports. Commodore sold a C16-family-specific Datassette and joysticks, but third-party converters to allow the use of the abundant, hence much less expensive, VIC-20/C64-type units soon appeared; the official reason for changing the joystick ports was to reduce RF interference. The C16's serial port was the same as that of the VIC-20 and Commodore 64, which meant that printers and disk drives, at least, were interchangeable with the older machines. For cost reasons, the user port, designed for modems and other devices, was omitted from the C16. Despite costing less than the Plus/4, the C16's keyboard was easier to type on; the Commodore 16 is one of three computers in its family. The even-less-successful Commodore 116 is functionally and technically similar but was shipped in a smaller case with a rubber chiclet keyboard and was only available in Europe; the family's flagship, the Commodore Plus/4, was shipped in a similar case but has a 59-key full-travel keyboard, 64 KB of RAM, a modem port, built-in entry-level office suite software.
Although shipped with 16k from the factory, it was possible to modify the C16 for 64k, making it able to run any Plus/4 software except applications that required the user port or built-in programs. Hardware designer Bil Herd notes that the C116 is the original member of this family of computers and is the original vision as imparted by Jack Tramiel to the engineering department, it was designed to sell for $49 to $79. The C16 and the Plus/4 came and were driven by the company trying to figure out what to do with the new computer family after Tramiel's departure from Commodore. In an early stage of development of the C16, Commodore was planning to have single layer PCBs built in as an attempt of cost reducing, it was the first and only attempt of Commodore using single layer PCBs inside their computers, only one such PCB is known to be preserved. The C16 was a major failure in the US and was discontinued within a year, but it sold reasonably well in Europe as a low-end game machine and in Mexico as well.
The C16's failure in the US market was due to a lack of software support, incompatibility with the C64, lack of importance to Commodore after its competitors withdrew from the market. A total of 1 million Plus/4s, C16s, C116s were sold, with the latter two accounting for about 60% of its total volume. Beginning in 1986, remaining C16, C116 and Plus/4 inventories were sold at a much reduced price on the Eastern Bloc market, chiefly Hungary. Hungary did not produce any home computers at the time, while the Soviet and East German models were far too expensive for most Hungarians, most Western models were out of reach. Th
The Commodore SX-64 known as the Executive 64, or VIP-64 in Europe, is a portable, briefcase/suitcase-size "luggable" version of the popular Commodore 64 home computer and the first full-color portable computer. The SX-64 features a built-in 1541 floppy drive, it weighs 10.5 kg. The machine is carried by its sturdy handle, it was announced in January 1983 and released a year at 995 USD. Aside from its built-in features and different form factor, there are several other differences between the SX-64 and the regular C64; the default screen color is changed to blue text on a white background for improved readability on the smaller screen. This can cause compatibility problems with programs; the default device for load and save operations is changed to the floppy drive. The Datasette port and RF port were omitted from the SX-64; because it has a built-in disk drive and monitor, Commodore did not perceive a need for a tape drive or television connector. However, the lack of a Datasette port poses a problem for a number of C64 Centronics parallel printer interfaces, since several popular designs "borrowed" their +5V power supply from the port.
This was not an issue for interfaces which were supplied with an AC adapter power supply, or those which can use the +5V line supplied by the Centronics port on the printer itself, if the printer implements it. Alternatively, a +5V supply is available from the joystick ports; the audio/video port is still present, so an external monitor can still be used. Differences electrically and in placement on the board, means that there are compatibility problems with some C64 cartridges; the original SX-64's power supply limits the machine's expandability. Compatibility with Commodore RAM Expansion Units varies. Early SX-64 power supplies cannot handle the extra power consumption from the REU; the physical placement of the cartridge port can prevent the REU from seating properly. The 1700 and 1750, 128K and 512K units intended for the C128, are said to work more reliably with the SX-64 than the 1764 unit, intended for the regular C64; some SX-64 owners modify Commodore REUs to use an external power supply in order to get around the power supply issues.
A version of the SX-64 with dual floppy drives, known as the DX-64, was announced, but the press reported by early 1985 that plans for its release had been suspended. A few have been reported to exist, but it is rare. Instead of an extra floppy drive, a modem could be built in above the first drive; some hobbyists installed a second floppy drive themselves in the SX-64's empty drive slot. SX-64 units use the larger power supply intended for the DX-64. A version with a monochrome screen called the SX-100 was never released; the SX-64 did not sell well, its failure has been variously attributed to its small screen, high weight, poor marketing, smaller business software library than that of its competitors, which included the Osborne 1 and Kaypro II and Compaq Portable. The exact number of SX-64 sold from 1984 to 1986, when it was discontinued, is unknown; the serial numbers of over 130 SX-64s from series GA1, GA2, GA4, GA5 and GA6, with serial numbers ranging over 49,000 for series GA1, 1,000 for GA2, 17,000 for GA4, 11,000 for GA5, 7,000 for GA6 have been reportedSome would-be buyers waited instead for the announced DX-64, which never became available due to the slow sales of the SX-64, creating a Catch 22 situation similar to that endured by Osborne after announcing an improved version of its computer.
The SX-64 did however gain a following with user groups and software developers, who could pack and unpack the machine to use for copying software or giving demonstrations. Ahoy! Favorably reviewed the SX-64, stating that the keyboard was better than the 64's, the monitor "isn't hard to read at all", the disk drive was durable enough for travel. While criticizing the lack of any provision for internal or external battery power, the magazine concluded that the average $750-800 retail price was "worth every penny!". Like the Commodore 64, except the following: Built-in storage: 170 kB 5¼" floppy disk drive Built-in display: 5" inch composite color monitor Keyboard: Separate unit, connected by cord to CPU unit Cartridge port: Placed on top of CPU unit, w/spring-loaded fold-in lid, cartridges inserted vertically I/O connectors: Serial "488" interface Video out connector User Port Cartridge Port No Datassette interface No RF modulator & connector Non-standard 25-pin keyboard connector below right side of front panel.
The connectors are similar but not identical to D-subminiature connectors and notoriously hard to find today Standard three-prong IEC C14 AC power connector Power supply: Internal unit with transformer and rectifiers Extra features: Floppy disk storage compartment above disk drive which could be used to build in an extra floppy drive or compatible sized modem SX64 Dot Net SX-64 schematics Commodore SX-64 Paper Model Disk Preservation Project Preserving original C64 hardware and software
The Commodore 128 known as the C128, C-128, C= 128, or CBM 128, is the last 8-bit home computer, commercially released by Commodore Business Machines. Introduced in January 1985 at the CES in Las Vegas, it appeared three years after its predecessor, the bestselling Commodore 64; the C128 is a expanded successor to the C64, with nearly full compatibility. The newer machine has 128 KB of RAM in two 64 KB banks, an 80-column color video output, it has keyboard. Included is a Zilog Z80 CPU which allows the C128 to run CP/M, as an alternative to the usual Commodore BASIC environment; the presence of the Z80 and the huge CP/M software library it brings, coupled with the C64's software library, gives the C128 one of the broadest ranges of available software among its competitors. The primary hardware designer of the C128 was Bil Herd, who had worked on the Plus/4. Other hardware engineers were Dave Haynie and Frank Palaia, while the IC design work was done by Dave DiOrio; the main Commodore system software was developed by Fred Bowen and Terry Ryan, while the CP/M subsystem was developed by Von Ertwine.
The C128's keyboard includes four cursor keys, an Alt key, Help key, Esc key, Tab key and a numeric keypad. None of these were present on the C64 which had only two cursor keys, requiring the use of the Shift key to move the cursor up or left; this alternate arrangement was retained for use under C64 mode. The lack of a numeric keypad, Alt key, Esc key on the C64 was an issue with some CP/M productivity software when used with the C64's Z80 cartridge. A keypad was requested by many C64 owners who spent long hours entering machine language type-in programs. Many of the added keys matched counterparts present on the IBM PC's keyboard and made the new computer more attractive to business software developers. While the 128's 40-column mode duplicates that of the C64, an extra 1K of color RAM is made available to the programmer, as it is multiplexed through memory address 1; the C128's power supply is improved over the C64's unreliable design, being much larger and equipped with cooling vents and a replaceable fuse.
The C128 does not perform a system RAM test on power-up like previous Commodore machines. Instead of the single 6510 microprocessor of the C64, the C128 incorporates a two-CPU design; the primary CPU, the 8502, is a improved version of the 6510, capable of being clocked at 2 MHz. The second CPU is a Zilog Z80, used to run CP/M software, as well as to initiate operating-mode selection at boot time; the two processors cannot run concurrently, thus the C128 is not a multiprocessing system. The C128's complex architecture includes four differently accessed kinds of RAM, two or three CPUs, two different video chips for its various operational modes. Early versions of the C128 experience temperature-related reliability issues due to the use of an electromagnetic shield over the main circuit board; the shield was equipped with fingers that contacted the tops of the major chips, ostensibly causing the shield to act as a large heat sink. A combination of poor contact between the shield and the chips, the inherently limited heat conductivity of plastic chip packages, as well as the poor thermal conductivity of the shield itself, resulted in overheating and failure in some cases.
The SID sound chip is vulnerable in this respect. The most common remedy is to remove the shield, which Commodore had added late in development in order to comply with FCC radio-frequency regulations; the C128 has three operating modes. C128 Mode has both 40 - and 80-column text modes available. CP/M Mode is able to function in both 40 - or 80-column text mode. C64 Mode is nearly 100 percent compatible with the earlier computer. Selection of these modes is implemented via the Z80 chip; the Z80 controls the bus on initial boot-up and checks to see if there is a CP/M disk in the drive, if there are any C64/C128 cartridges present, or if the Commodore key is being depressed on boot-up. Based on these conditions, it will switch to the appropriate mode of operation. In 1984, a year before the release of the Commodore 128, Commodore released the Plus/4. Although targeted at a low-end business market that could not afford the high cost and training requirements of early IBM PC compatibles, it was perceived by the Commodore press as a follow-up to the 64 and would be expected to improve upon that model's capabilities.
While the C64's graphics and sound capabilities were considered excellent, the response to the Plus/4 was one of disappointment. Upon the Plus/4's introduction, repeated recommendations were made in the Commodore press for a new computer called the "C-128" with increased RAM capacity, an 80-column display as was standard in business computers, a new BASIC programming language that made it easy for programmers to use the computer's graphics and sound without resorting to PEEK and POKEs, a new disk drive that improved upon the 1541's abysmal transfer rate, as well as total C64 compatibility; the designers of the C128 succeeded in addressing most of these concerns. A new chip, the VDC, provides the C128 with an 80-column color CGA-compatible display; the then-new 8502 microprocessor is backward-compatible with the C64's 6510, but can run at double the speed if desired. The C64's BASIC 2.0 was replaced with BASIC 7.0, which inc