Acorn Archimedes

The Acorn Archimedes was one of 1987 produced until the mid- 1990s computer series from Acorn.

Performance

The Archimedes was characterized by a very high for that time Home computer speed, which he owed to the ARM microprocessors specially developed. Acorn Archimedes was the first RISC computer that was made ​​available to the wider public.

From work to speed, the 8 MHz clocked and then about 3500 DM expensive Archimedes outperformed most other computer systems in the price range to about 20,000 DM first Archimedes models ( A305 and A310 ) and A3000 wore on the keyboard next to the Archimedes Logo or the text " British Broadcasting Corporation Microcomputer system" and had the typical BBC computer red function keys.

A PC emulator made ​​it possible to have PC programs run, and indeed almost with the speed of a real PC.

Graphic

The Acorn Archimedes mastered without interlace higher resolutions up to 1152 × 896 in 2 colors and 640 × 512 at 256 colors. In its graphics chip ( VIDC ) to resolutions and color depths within wide limits could be programmed as desired, but this presupposed a correspondingly flexible monitor (very popular was the Multisync II, NEC ). The Archimedes was able to choose from a total of 4096 colors, one of which could be displayed simultaneously, depending on the mode 2, 4, 16 or 256.

The Archimedes mastered only a hardware sprite ( which was used primarily as a mouse pointer). In addition, he had no special graphics chips so that game development was difficult. Nevertheless, there was also the Archimedes elaborate games, including conversions of Amiga games that corresponded to their originals.

The operating system RISC OS already supported vector fonts and many more features, so it was relatively easy for programmers to use it in complex applications. Impressively shows that when included in the ROM of the Archimedes program! Draw, which is functionally able to compete with the former versions of Corel Draw, but also ran faster and was completely contained in the ROM of the computer.

Sound and Music

The Archimedes offered, as with today's sound hardware common to only one DMA channel and had to assemble the audio data of each channel before output via software. The output of the samples was not linearly realized, but logarithmically converted what the human ear comes closer than the linear conversion now commonly used. Characterized could be obtained with the 8 - bit samples, a dynamic range of approximately 12 bits. The operating system of Archimedes set 8 votes available. 16 -note tracker as that! Coconizer were available.

Operating system

The operating system RISC OS was integrated in ROM. In addition to the entire graphical interface it included already numerous additional programs like! Paint ( a bitmap drawing program )! Draw ( a vector-oriented desktop publishing program )! Edit ( write a program). The Archimedes programs started in the so-called taskbar, the licensed Microsoft for Windows 95. Included were also the CLI (Command Line Interpreter ), a complex, modeled on Unix operating system shell, the batch was run, and the BBC BASIC, which also included an in-line assembly language.

RISC OS 2 allowed so that the system booting without hard disk or floppy. Settings are saved in a battery-backed CMOS RAM. RISC OS 3 was also able to boot without a floppy or hard disk, but boot floppies are included that have reloaded several extensions.

The operating system offered cooperative multitasking. Cooperative means that the applications from RISC OS were called and again independently completed a cycle so that the RISC OS was passed to the next application. The memory controller MEMC Archimedes could all memory Umblenden (Memory Mapping), so that each program was carried out apparently in the same memory area and of the other programs saw nothing.

The operation took place almost exclusively with the mouse, which was equipped with three buttons. With the middle mouse button was open to all objects on the desktop and in the programs shortcut menus. The operating system supported through drag and drop.

The task manager of the RISC OS listed on all programs and their resource consumption.

However, the system is less protected by the cooperative multitasking against program error than systems with pre-emptive multitasking, such as Windows NT or Unix derivatives, since the programs to control independently must transfer to the operating system by operating system call again. The crash of a program was thus, as far as the error did not finish the program sometimes crash the whole computer. The low incidence of problems is motivated by the fact that there was no dynamic link libraries, but only the single ROM with the firm and relatively low-error modules.

Programming of Archimedes

The built- in ROM BBC BASIC also supported inline assembly language. The graphical user interface of the first Archimedes operating system, ARTHUR, was still partially programmed in BBC BASIC. The later operating system RISC OS was finally written entirely in assembly language.

For the operating system calls the ARM offered its own assembler instruction, SWI (software interrupt). How could the operating system functions from the assembler in the form of, for example, SWI " OS_WriteC " ( for Write Character ) are called. As parameters were used here, the 16 registers of the ARM. Detailed manuals listed the all SWIs of RISC OS and documented the inputs and outputs of the registers and functions.

Own operating system calls could be programmed via new modules and extended the operating system as required.

Archimedes models

  • Archimedes A305 (1987 ), the entry level model with ARM2 CPU at 8 MHz, 512 KB RAM, was usually already upgraded by the dealer to 1 MByte in Germany (where the A305 - lettering was pasted over with an A310 lettering )
  • Archimedes A310 (1987 ), such as A305, with 1 MB of RAM
  • Archimedes A410, was indeed (multiple) announced but was (probably ) never really available
  • Archimedes A440 (1987 ), such as A310, but with 4 MB RAM, ST -506 disk controller and a hard drive with 20 MB
  • Archimedes A410 / 1 (1989), such as A440, but with a new (around 10% faster ) Memory Controller MEMC1a, 1 MB of RAM and no hard drive
  • Archimedes A420 / 1 (1989), such as A410 / 1, but with 2 MB
  • Archimedes A440 / 1 (1989), such as A410 / 1, but with 4 MB of RAM and a ST506 hard disk with 53 MB
  • Archimedes A540 (1990 ), the first Archimedes with ARM3 CPU with 26 MHz, 4 MB RAM (expandable to 16 MB ) and optional math co, SCSI hard disk drive with 100 MB

The following models were not considered by Acorn Archimedes as, but are technically almost identical to the Archimedes:

  • A3000 (1989 ), computer keyboard, similar to the Amiga 500 (or the BBC Master 128)
  • R140 (1989 ) as A440 / 1, but with a hard drive with 60 MB and (in addition to RISC OS) with RISCix (Unix derivative)
  • R260 (1990 ), such as A540, but 8 MB RAM, a SCSI hard disk drive with 100 MB, Ethernet interface and RISCix
  • R225 (1990 ), such as R260, but with 4 MB RAM and no drives
  • A5000 (1991 ), ARM3 with initially 25 MHz (obtained so that the A540 as a top model remained ), and later with up to 33 MHz and optional math co ( FPA10 ), the first model with standard IDE controller, and 2 Mbytes (gross) floppy drive
  • A3010 (1992 ), keyboard computer, ARM250 (processor ARM2, memory controller MEMC1a, IO controller IOC and graphics chip VIDC1a in a chip combines ), 12 MHz, 1 MB RAM, 1.6 MB floppy, the first and only " Archimedes " with built-in joystick ports and TV modulator
  • A3020 (1992 ), such as A3010, but with 2 MB RAM, no joystick ports, no TV modulator, but with built-in IDE controller and optional hard disk
  • A4000 (1992 ), designed specifically for British schools " hybrid" between A3020 and A5000, as the A5000 with remote keyboard, but technically at the level of the A3020 ( ARM250, 12 MHz)
  • A4 ( 1992), the notebook, which was technically the predecessor of the A5000 (although it only after it came on the market ), with ARM3 (24 MHz), 4 MB of RAM and a grayscale display with 640 × 480 pixels, the case was identical to the station Walk of Triumph-Adler and the S20 Olivetti (at the time Acorn was 79 % owned by Olivetti ). It had no built-in pointing device such as a trackball or touchpad.
  • A7000 (1995 )
  • A7000 ( 1997)

Successors were the Risc PCs from Acorn.

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