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RiscPC

Acorn Risc PC 600 with 2 case slices, 3.5" disk drive and DVD-ROM drive.
Developer	Acorn Computers
Manufacturer	Acorn Computers, Castle Technology
Release date	April 15, 1994 (1994-04-15)
Discontinued	November 11, 2003 (2003-11-11)
Operating system	RISC OS
CPU	ARMv3/ARMv4
Dimensions	117 mm (4.6 in) (h) 355 mm (14.0 in) (w) 384 mm (15.1 in) (d)
Predecessor	Archimedes series
Successor	Phoebe, Iyonix PC, A9home
Related	A7000

The Risc PC (codenamed Medusa) was Acorn Computers's next generation RISC OS/Acorn RISC Machine computer, launched on 15 April 1994, which superseded the Acorn Archimedes.

Like the Archimedes, the Risc PC continued the practice of having the RISC OS operating system in a ROM module. Risc PC augmented the ROM-based core OS with a disk-based directory structure containing configuration information, and some applications which had previously been kept in ROM.

Specifications and technical details

• Memory type: SIMM, 2 slots, supporting a maximum memory size of 256 MB.
• Video subsystem: VIDC20 controller, with optional dual-port VRAM up to 2 MB.
• Expansion: Eurocard-sized Podule support in common with Archimedes-series machines. The Risc PC also offers DMA support in the first two podules on the bus.
• Operating System: RISC OS

RISC OS 3.5 (Risc PC 600)
RISC OS 3.6 (Risc PC 700)
RISC OS 3.7 (StrongARM Risc PC)
Fitted as standard

RISC OS 4, RISC OS Select, RISC OS Adjust and RISC OS 6
are available from RISCOS Ltd as a replacement for the Acorn-implemented versions which came fitted as standard.
Linux was ported but is no longer supported.
NetBSD has been ported.

• Case: Designed by industrial designer Allen Boothroyd of Cambridge Product Design (designer of the BBC Micro case). Custom plastic-based design with a novel 'slice' feature which allows extra case modules to be added to increase internal expansion space. Each slice adds 2 podule bays at the rear, and two drive bays (one 3.5 inch, one 5.25 inch) at the front, covered by a retractable flap to hide cosmetic inconsistencies in hue. Some slices were internally sprayed with nickel paint to meet electromagnetic and radio emissions regulations.
• Ports: Serial, Parallel, PS/2 keyboard, Acorn mouse, headphone audio out, DE15 VGA, network (optional).
• CPU: Dual-processor slots, accepting the following chips on a special daughterboard: ARM610 at 30 MHz or 33 MHz, ARM700 at 33 MHz (only as prototype), ARM710 at 40 MHz, ARM810 at 55 MHz (only as prototype), StrongARM at 203 MHz, 236 MHz or 300 MHz. 486 and 586-based co-processors at up to 133 MHz, and DSP chips (third party) were also available. A Hydra multi-processor development system from Simtec allowed an extra four ARM6 or ARM7 CPU cards. The Hydra add-on added multiprocessor functionality to the RiscPC with multiple Acorn ARM610 processors and the addition of the x86 Co-processor card.

• Dimensions: 117 (182 two centre-sections) x 355 x 384 mm (HxWxD).

Milestones

1994 – Risc PC 600 launched, featuring a 30 MHz ARM6 CPU.
1995 – ARM7 CPU upgrade and Risc PC 700 model launched.
1996 – StrongARM CPU upgrade released, offering a fivefold increase in raw processing power compared to the ARM7 used in the previous high-end machines.
1998 – Castle Technology acquire the rights to continue to market and produce the Risc PC during the breakup of Acorn Computers.
2000 – In May, Castle Technology revealed the Kinetic Risc PC range which included a faster processor card with onboard memory.
2001 – Viewfinder Podule, AGP adapter allows the use of IBM P.C. clone AGP graphics cards (e.g. a range of ATI Rage and Radeon).
2003 – Castle Technology announce the end of production and sale of the Risc PC.

Risc PC 2

Acorn set about designing the Risc PC 2, later renamed to Phoebe 2100 – a design with a 64 MHz front side bus, PCI slots, and a yellow-coloured NLX form-factor case. Slated for release in late 1998, the project was abandoned just before completion, when Acorn's Workstation Division was closed. Only two prototypes were ever built, and one was publicly displayed for historical interest at the RISC OS 2001 show in Berkshire, England; the remaining cases were bought by CTA Direct who sold them off to the public.

Risc PC today

In 2003 it was confirmed that no more Risc PCs would be produced. However RISC OS computers based on other ARM processors machines have been manufactured by companies since this date.

• Castle Technology – Iyonix PC based on the Intel XScale ARM processor and PCI bus.
• Advantage Six – A9home based on the Samsung S3C2440 ARM processor
• RiscStation – R7500 based on the ARM7500-FE processor.

Second-hand Risc PCs command very high prices relative to PCs of similar age and specifications . Significantly better performance has been pulled out of the aged Risc PC design by using the newer 203 (and later 236) MHz StrongARM CPU, using third-party video cards, overclocking, and having specially-designed CPU cards with RAM located upon them to sidestep the speed bottleneck of the slow system bus.

Limitations

The 16 MHz front side bus is usually recognised as being the most significant fault of the computer; and the arrival of the (five times faster) StrongARM processor in 1996 meant that the Risc PC had a CPU significantly faster than that for which the computer had been designed. Acorn had originally expected ARM CPUs to progress from the 30 MHz ARM6 to the 40 MHz ARM7, and then onto the ARM8 cores, which at the time were clocked at around 50-80 MHz. In 2000, Castle released "Kinetic", a new StrongARM processor board with its own onboard memory slots augmenting main memory, reducing the need to negotiate the slow front side bus for memory accesses.

The podule bus on the Risc PC (i.e. 32-bit, on predecessor systems to the Risc PC: 16-bit) can achieve a maximum data throughput of approximately 6100 KByte/s. For comparison: the PCI bus, which was available in systems at the time of the Risc PC's introduction, is over 20 times faster (e.g. the transfer of 650 MB would take 2 minutes, compared to 5 seconds via PCI).

See also

• Acorn A7000

References

1. "Acorn announces distribution deal with Castle Technology for RISC based products". Press release. Acorn Computers Ltd. 1998-10-12. Archived from the original on 1999-05-06. Retrieved 2011-01-06. (October 12th 1998), Cambridge, UK-Acorn announced today that it has completed negotiations with Castle Technology for them to distribute Acorn products. {{cite news}}: |first= missing |last= (help)
2. ^ "Acorn launches the Risc PC" (PDF). Developers' Newsletter No. 33 – April 1994. Acorn Computers. 1994-04-30. Retrieved 2011-02-11. on Friday April 15th
3. Mike Williams (November 11, 2003). "Risc PC to Cease Production". Newsgroup: comp.sys.acorn.announce. slrnbr2fvo.ngt.n.g.boalch@compsoc.dur.ac.uk. Retrieved February 14, 2011.
4. ^ "Chris's Acorns: Risc PC Computers". Chris Whytehead. 2009. Retrieved August 19, 2009.
5. "Chris's Acorns: RISC OS Ltd". Chris Whytehead. 2009. Retrieved August 19, 2009.
6. "ARM Linux Acorn Overview". ARMLinux. 2009. Retrieved August 13, 2009.
7. "NetBSD/acorn32". NetBSD. 2009. Retrieved August 13, 2009.
8. Penman, Danny (1994-04-15). "Computers: System that holds the right cards". The Independent. London. Retrieved September 06, 2011. The modular design of the new computer allows a PC 486 processor to be added using a card {{cite news}}: Check date values in: |accessdate= (help)
9. "Chris's Acorns: ART StrongARM CPU". Chris Whytehead. 2009. Retrieved August 19, 2009.
10. ^ "Castle bids farewell to RiscPC". Drobe. 2003. Retrieved August 13, 2009.
11. "Castle reveal Kinetic to the press". Iconbar. 2000. Retrieved August 13, 2009.
12. "Viewfinder 2 revealed". Drobe. 2002. Retrieved June 28, 2010.
13. "Clan Newsletter August 1998". Acorn Computers. 1998. Retrieved August 19, 2009.
14. "RiscPC 2 at RISC OS 2001". Drobe. 2001. Retrieved August 13, 2009.
15. "Phoebe cases on sale". Iconbar. 2000. Retrieved August 19, 2009.
16. Podule Bus review

External links

• Acorn's famous 10-slice Rocket Ship RiscPC, including pizza oven and kitchen sink
• Advantage six reveal A9Home to the press
• Castle reveal Kinetic Risc PC to the press
• Risc PC 10th Birthday
• Risc PC production ceases

• Personal computers