website/content/museum/acorn-computer-risc-pc.md

title, categories, types, origins, years, cpus, params

title	categories	types	origins	years	cpus	params
Acorn Computer Risc PC	Computers	Professional Computer	United Kingdom	1994	ARM 610	name image company company_name specs tabs forum_thread photos adverts hardware oc_id source Risc PC /media/museum/photos/acorn_riscpc_system_s1.jpg /companies/acorn-computer Acorn Computer label value NAME Risc PC label value MANUFACTURER Acorn Computer label value TYPE Professional Computer label value ORIGIN United Kingdom label value YEAR 1994 label value BUILT IN LANGUAGE BBC Basic label value KEYBOARD Full 102 Key PS/2 PC style label value CPU ARM 610 label value SPEED 30 MHz label value CO-PROCESSOR Choice of IBM-PC CPU’s including 486/586 label value RAM 4 MB (Up to 256 MB) label value ROM 4 MB containing most of the OS label value GRAPHIC MODES Numerous - 1280 x 1024 at 256 colours, 800 x 600 16M colours label value COLORS Full 24bit 16M colours (video memory permiting) label value SOUND 16bit stereo 8 voice synthesiser (PC sound blaster compatible) label value SIZE / WEIGHT 35.5 (W) x 38.5 (D) x 12 (H) cm label value I/O PORTS Parallel, RS232, 2 x PS/2, VGA, 3.5mm sound jack, single width expansion slots (two per ‘slice’) label value BUILT IN MEDIA 3.5'' floppy disk, 3.5'' IDE hard disk, CD-ROM label value OS RISC OS 3.5 (mainly in ROM, aditional resources on hard disk) label value POWER SUPPLY Built-in switching power supply unit label value PRICE From around £1200 photos adverts hardware 989 title subtitle text image LARGE VIEW The rounded front plastic cover slides inside the machine. /media/museum/photos/acorn_riscpc_system_s2.jpg title subtitle text image SIDE VIEW A nice case design /media/museum/photos/acorn_riscpc_rightside_s1.jpg title subtitle text image RISC AND WINDOWS OS'S The same machine could run alternately RISC OS-3.5 or MS-Dos/Windows OS's thanks to a second Intel processor card. /media/museum/photos/acorn_riscpc_dualos.jpg title subtitle text image REAR CONNECTORS **(1)** Rsset switch\ **(2)** Stereo sound output jack\ **(3)** 15-pin video output plug\ **(4)** Keyboard mini-Din plug. Any standard PC/AT keyboard can be connected\ **(5)** Acorn mouse mini-Din plug\ **(6)** Expansion slots\ **(7)** Parallel printer DB25 connector\ **(8)** Serial DB9 connector. /media/museum/photos/acorn_riscpc_backside_s1.jpg title subtitle text image MAGIC CASE #1 The base unit and the first 'slice' holding the floppy and CD-ROM drives. Up to eight slices could be stacked to expand the system. /media/museum/photos/acorn_riscpc_storageunit.jpg title subtitle text image MAGIC CASE #2 /media/museum/photos/acorn_riscpc_inside_s2.jpg title subtitle text image MAGIC CASE #3 This working system had 10 slices and an array of gadgets including a working pizza oven and remote controlled sink!!! More detailed information [here](http://www.worldofwibble.com/aboutriscpc.html). /media/museum/photos/acorn_riscpc_pizza.jpg title subtitle text image MAIN BOARD **(1)** IDE hard disk, here a 1 GB model.\ **(2)** Floppy disk and hard disk connectors\ **(3)** IOMD20 - I/O controller and memory manager custom chipset\ **(4)** Connector of the ARM processor card\ **(5)** Connector of the Intel/PC processor card\ **(6)** Floppy disk and hard disk controller chipset\ **(7)** 256 MB ROM chips holding the RISC OS, here the 3.6 version\ **(8)** Network card connector\ **(9)** RAM module connectors\ **(10)** Video controller custom chipset\ **(11)** Backplane slot. Early RiscPCs came with the backplane for plugging in Podule cards. /media/museum/photos/acorn_riscpc_inside.jpg title subtitle text image PROCESSOR CARDS The twin processor cards hold the ARM processor and the Intel-PC processor, here an ARM 710 and a Texas Instruments 486DX-4/100. /media/museum/photos/acorn_riscpc_proccards_s1.jpg title subtitle text image ADVERTISING PICTURE /media/museum/pubs/acorn_riscpc_pub_s1.jpg title subtitle text image ARM 710 PROCESSOR CARD /media/museum/hardware/acorn_riscpc_arm710card_s1.jpg title subtitle text image 486 PROCESSOR CARD /media/museum/hardware/acorn_riscpc_486card_s1.jpg 1015 url date https://web.archive.org/web/20230609185904/http://www.old-computers.com/museum/computer.asp?c=1015 2023-06-09

In April 1994, Acorn announced the release of the second generation of ARM machines – the Acorn RISC PC 600. Code named the Medusa project, this was set to replace the then ailing flagship A5000 machine.

As the name suggests, one of the main features of this computer was that it could run both Acorn and IBM-PC software side by side. This was achieved by a second CPU slot that could accept a daughter board with a PC CPU, such as a 486 or 586. This second processor then had shared access with the primary CPU to all the system resources. No more CPU intensive software PC emulation required!

As well as the second processor, other major enhancements included an updated video controller with the option for dedicated video RAM. The graphics chip in previous Archimedes range machines had shared the system memory with the rest of the computer which often proved to be a bottle neck without true DMA. Now the video controller could have video memory of it’s own, removing the bottle neck.

The system data bus was doubled in size to 32bits wide, and the MEMU and IOC chips were combined to create the IOMD20. This resulted in much better overall I/O, yet another bottle neck removed from previous machines. The system memory was also upgraded to a maximum of 256MB and the memory bus was designed to use the more widely available EDO SIMM’s.

A unique feature of the RISC PC was its case. This came in the form of the base holding the motherboard and power supply, a mid section for mounting one 3.5" device, one 5.25" device and two single width expansion cards, and then a lid. The magic was that you could add up to 8 slices at any time, giving you a very easily expandable computer, and all held together with clips and springs negating the need for a screwdriver. Very neat.

There were 2 other Acorn RISC PC's. The RISC PC 700 was released July 1995 and the RISC PC-2 was much publicised by Acorn and then dramatically cancelled at the last minute.

Thanks to Paul Hadfield for his kind help.