Risc PC
The Risc PC is a RISC- based computer from Acorn . Like its predecessor, the Acorn Archimedes , he has an ARM - CPU , operating system is RISC OS used in version 3.5 or later. The first Risc PC was presented in 1994 with an ARM610 processor clocked at 30 MHz; a year later a model with ARM710 (40 MHz) appeared. In 1996 the significantly faster StrongARM processor (up to 287 MHz) was available for the Risc PC.
technical description
A basic version of the operating system is stored in exchangeable ROM modules so that the computer can be started without a hard disk. The widespread EDO-SIMMs were used as working memory, which , unlike the Archimedes, no longer had to share the main processor with the graphics card, but could still be used if no graphics RAM module was inserted. The main memory could be upgraded to a maximum of 256 MiB. The system has two slots for processor plug-in cards, one of which is the main processor of the system. Another processor can be installed in the second slot, which makes it possible to upgrade to newer processors without any problems. For example, a 486 can be used as a second CPU in order to operate it as an “ embedded PC ”. This makes it possible to run DOS or Windows under RISC OS. The housing is almost screw-free, has a modular structure and is very easy to open.
Basic technical data
These data are the same for all models.
- Modular housing with proprietary power supply and mono speakers
- IOMD - input, output and memory controller ASIC
- VIDC20 - video & sound controller ASIC
- Operation with and without VRAM possible, without VRAM recourse to shared memory method
- SVGA ( 800 × 600) with 32 bit color depth
- XGA (1024 × 768) with 16 bit
- UXGA (1600 × 1200) with 8 bits
- Sound: 8 bit logarithmic (Issue 1 and Issue 2 mainboards) or 16 bit linear samples (Issue 3 mainboards)
- Open processor architecture (2 processor slots, 1 of which is occupied by an ARM card)
- 2 × 72 pin SIMM socket for PS / 2- / EDO-RAM up to 256 MB (2 × 128 MB)
- 1 × VRAM socket for a DIMM module with 1 or 2 MB, experimentally also with more memory
- 2 × ROM sockets for RISC OS ROMs
- 1 × network adapter socket for Ethernet or Econet network cards
- 240 byte battery-backed CMOS-RAM for basic configuration and real-time clock
- DEBI expansion bus with full DMA support for slot 0 and 1 (counting starting on the motherboard from 0 to 7)
- DEBI: DMA Extended Bus Interface
- up to 8 slots with a 4-tier backplane
- Socket for 16-bit sound card (only Issue 1 and 2 mainboards, Issue 3 mainboards had 16-bit sound on board)
- 1 × mixer connection for analog audio (only Issue 3 mainboards)
- 1 × IDE / ATAPI connection for up to 2 IDE / ATAPI drives ( hard drives , CD-ROM , removable disks, tape drives )
- 1 × floppy connector
- When it comes to the floppy connection, there were two different models for the Risc PC 600, which differed in that one model only supports one drive, while the other supports two.
- Connection of 3.5 ″ and / or 5.25 ″ disk drives (SD and HD)
- 3.5 ″ formats: 1.6 MB ( ADFS ), 1.8 MB (ADFS Extended), 1.44 MB (FAT), 800 kB (ADFS), 720 kB (FAT, ATARI)
- All connections on the back
- PS / 2 keyboard connector
- Logitech Mousebus mouse connector (mechanical three-button mouse included)
- 1 × parallel port, bidirectional
- 1 × serial port, 115200 bit / s
- 1 × 3.5 mm stereo jack plug audio out
- 1 × VGA D-Sub 15 connection
- External connections of all expansions are led out of the housing to the rear
Models
| model | Risc PC 600 | Risc PC 700 | Risc PC SA |
|---|---|---|---|
| Launch | 1994 | 1995 | 1997 |
| processor | ARM 610 | ARM 710 | Strong ARM |
| RISC OS | 3.5 | 3.6 | 3. |
The Risc PC first appeared under this name. The name extensions with trailing numbers (600,700) were only introduced after the appearance of the processor card with the ARM710.
The Risc PC was originally delivered with an ARM610 processor card and 4 MB RAM as well as a 210 MB hard disk. At the time, the mainboard only had 8-bit sound and the VideoRAM was initially only installable up to 1 MB, as the 2 MB bars were initially not available. This machine was offered in various combinations with Acorn's own monitors (AKF60, AKF85), a larger hard disk (420 MB), a CD-ROM, the 1 MB VideoRAM module, expansion to 8 MB RAM.
The direct predecessor machine, the A5000, could contain 4 MB RAM by simply expanding it with a 2MB plug-in module or had it soldered directly onto the board as a maximum expansion; more complex conversions (retrofitting a MEMC memory controller for each additional 4 MB and installing a socket for the original MEMC) made 8 MB or 12 MB RAM possible. Therefore, the basic 4 MB RAM of the Risc PC was quite generous at the time.
The purchase price of the Risc PC in Germany for the small model (ARM610.4MB, 210HDD) was exactly 2999 DM.
Important hardware extensions that were available individually from Acorn were a plug-in sound module with 16-bit sound output (i.e. CD quality), the VideoRAM upgrade, and the PC compatibility card.
From Acorn's point of view, the latter was an essential part of the overall understanding of the machine - the entire device is designed with this option in mind (OpenBus). It initially appeared in the form of a version equipped with a 486SX from Texas Instruments . This certainly allowed the operation of DR-DOS from the scope of delivery, but also of MS-DOS , Windows 3.1 , later Windows 95 . However, of course, with limited gaming capabilities.
Due to its modular structure, the Risc PC can be expanded step by step. In the course of time, the manufacturer itself also offered additional processor cards, RAM modules, network cards, PC cards, and sold certain combinations as complete devices under their own official device number (ACBxx). Therefore, there are also “milestones” of development with a special designation, as in the table above.
During the manufacturing period, the mainboard was slightly revised twice, but the main features remained essentially unchanged. The third version then already contains 16-bit sound on-board and a video unit adapted to European standards (which did not improve the picture).
This also means that you do not have to rely on a suitable newer board to operate a StrongARM card, for example. Instead, devices of the first or second generation can also be upgraded to a full configuration. Often a ROM exchange is still necessary because the OS must also support the new processor.
Acorn itself planned an upgrade path from the ARM600 via the ARM700 (1995) to an announced ARM800. In addition, there were fixed, guaranteed upgrade prices when the Risc PC was introduced, in order to enable a planned upgrade. All these chips were planned with clock rates in normal chip evolution, starting with the 30 MHz of the ARM610 in the Risc PC (comparison with A5000 25Mhz or 33 MHz and A540 with 26 MHz, all with ARM3). The ARM710 processor card of the Risc PC 700 was operated at 40 MHz and was approx. 25% faster than the ARM610.
In 1996 the StrongARM CPU appeared, which was developed by the Digital Equipment Corporation (DEC) with and for ARM. Much of Digital's knowledge of manufacturing high-speed RISC processors such as the Alpha processor was incorporated into their development . Among other things, there were separate caches for data and instructions ( Harvard architecture ) instead of the simple cache of the older ARM processors, and the instruction pipeline was extended from three to five levels. When using this chip in the Risc PC, this resulted in some changes in the operating system ( RISC OS 3.7 required) and many programs. In return, the StrongARM card was a processor card available at the end of 1996 that again provided high computing power for microcomputers at a clock rate of 202 MHz.
particularities
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The second processor slot is a hardware solution that is rarely found in this form, as it allows a second processor of completely different design (ARM vs. x86) in real parallel operation to control the entire system bus including all devices (RAM, graphics, I / O), albeit under the condition that the actual bus master must always be an ARM processor, which must therefore also be plugged into the first slot. The second processor is connected to the system via a special IC, which can be found on all PC cards and which converts it to the bus protocol of the Risc PC.
In this sense, it is also not a dual or multi-processor system of the type known from other manufacturers, such as SUN SPARCstation 10, SUN Ultra 2, SGI Octane or the Abit BP6 mainboard for Celerons.
Acorn also tried to operate the Risc PC in dual processor mode. The expression for this is the existence of a processor card with another ARM610, the Acorn "Duet" card.
This approach was also followed by the English company SIMTEC Electronics and took shape in the form of a whole plug-in card system called Hydra with which up to 5 (!) ARM processor cards can be installed on the 2 existing processor slots. In contrast to the Duet card, the Hydra Multiprocessor Board was actually available for purchase and demonstrated using a Mandelbrot generator.
The Dortmund-based company ACE (Acorn Computer Enterprises) produced a switching board, the ARM switcher, which made it possible to have two different ARM processors installed in the Risc PC and to be able to decide which CPU to use when starting up before switching on. This was probably a sensible solution, especially during the transition and the adaptation to the StrongARM architecture, as it meant that existing software could continue to be used.
The Acorn 1994 also announced media processors (eg DSP , MPEG - Decoder or graphics accelerator) for the second processor slot never became generally available in this form. Perhaps this would have been a better option to use the slot; However, this was contradicted by the need for PC compatibility, to which all manufacturers with their own system architecture were subject or believed to be subject to.
The housing can be modularly expanded using several housing parts that can be stacked one on top of the other. The first lowest level is already structurally identical to all potentially following. A base plate holds the mainboard as well as the power supply unit and a hard disk installed on the front. Each additional level module offers space for a further 5.25 ″ drive and a 3.5 ″ slot, for example for floppies or other hard disks. All modules are held together and locked to the base plate by a total of four plug-in and rotatable pins on the corners of the housing. Expansion slots for plug-in cards, so-called podules, are arranged vertically via a riser card , which Acorn calls a backplane. Two expansion slots are possible for each level module. A housing with two levels can therefore accommodate four plug-in cards if the corresponding backplane is available; higher housing accordingly more. In the standard housing with one level, there are only the lower two slots, which are DMA-capable. Cards that support this mode (e.g. SCSI controller) should therefore be installed here. From four slots at the latest, the power supply must be taken into account, which in the Risc PCs is not designed for large full-scale configurations. There are two different power supply units with 70 watts and 103 watts of power.
Probably the most complex and most remarkable Risc PC structure is the machine presented at the Acorn World Show in November 1996 with a total of ten housing levels, which has become known under the name "The Rocket Ship Computer".
successor
The official Risc PC successor Phoebe or Risc PC-2 was never completed by Acorn. In 2000 the Kinetic Risc PC with StrongARM, RISC OS 4 and memory on the CPU card appeared. This was built and sold by Castle Technology Ltd., a supplier of additional hardware for the Acorn devices, after the end of Acorn. Castle Technology Ltd. later, in December 2002, released its own successor to the Risc PC based on the XScale processor, the IYONIX pc .
From the British company MicroDigital there was a particularly interesting device whose most important hardware components were represented by FPGAs ( Field Programmable Gate Array ), the Omega . This would have made hardware adjustments possible through software updates. Unfortunately, the time of the first demonstrable stable operation coincided with the appearance of the IYONIX PC, which prevented the Omega from being a great commercial success. But he deserves the honor of many former users of the RISC OS for maintaining the hope of a new generation of hardware after the break-up of the Acorn company .
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The A9home was a small mini computer from Advantage Six from 2005. Smaller than the Mac Mini , which appeared around the same time, it is, like the IYONIX PC, a newer generation device with a full 32-bit address bus . The A9home already indicates the transition to small devices with boards in mini format or even fully integrated systems in one chip , such as the Raspberry Pi .
Miniaturization has also not stopped at the housing, which is good for commercial devices such as BIK ( BeagleBoard -In-Kiste) (in England as ARMini ) from 2010 or PIK ( PandaBoard -In-Kiste) (in England as ARMiniX ) from 2011 reveals. Nowadays, using 3D printing, a self-made housing based on the large model is possible.
Currently current follow-up systems are up to 140 times faster than a riscpc and based u. a. on the BeagleBoard , the Wandboard, the Titanium from Elesar or the Raspberry Pi in all its versions.
Web links
- Title page of the first edition of RiscPC Magazin , the only German magazine that ever appeared for Risc PC (2 editions).
- A serial 3-button mouse can be configured to start up the device without the proprietary Acorn mouse .
- RISCy Business - The Acorn RiscPC - ARM in a desktop on YouTube , March 30, 2018, accessed on July 25, 2018. Comprehensive and descriptive video about the RiscPC (in English).
- Freely available version of the RiscPC emulator (also commercially available in extended form) (virtualacorn.co.uk).
- Happy Birthday RiscPC on YouTube , May 3, 2014, accessed on July 25, 2018. Celebration of the 20th anniversary, 1994–2014
Individual evidence
- ↑ https://bernd-leitenberger.de/cisc-risc.shtml
- ↑ a b c Archived copy ( memento of the original dated November 21, 2010 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ a b http://acorn.chriswhy.co.uk/Computers/RiscPCComputers.html
- ↑ a b http://chrisacorns.computinghistory.org.uk/Computers/RiscPCComputers.html
- ^ Technical Reference Manual, Issue 1 September 1994, Acorn Computers Ltd.
- ↑ http://www.old-computers.com/museum/photos.asp?t=1&c=1015&st=1
- ↑ http://chrisacorns.computinghistory.org.uk/docs/Acorn/DN/Acorn_DevNL33.pdf
- ↑ http://www.nxp.com/documents/data_sheet/PCF8583.pdf
- ↑ http://www.computinghistory.org.uk/det/10679/Acorn-Risc-PC-600-ACB60/
- ↑ http://www.computinghistory.org.uk/det/33639/Acorn-RISC-PC700-System/
- ↑ http://www.riscos.com/the_archive/acorn/processor/arm610/index.htm
- ↑ http://www.riscos.com/the_archive/acorn/processor/arm710/index.htm
- ↑ http://www.riscos.com/the_archive/acorn/processor/strongarm/index.htm
- ↑ http://chrisacorns.computinghistory.org.uk/32bit_UpgradesA2G/Acorn_ARM610_CPU.html
- ↑ http://chrisacorns.computinghistory.org.uk/32bit_UpgradesA2G/Acorn_ACA42_PCcard.html
- ↑ https://archive.org/stream/AcornUser162-Dec95#page/n50/mode/1up
- ↑ http://chrisacorns.computinghistory.org.uk/32bit_UpgradesA2G/Acorn_ARM710_CPU.html
- ↑ https://archive.org/stream/AcornUser157-Jul95#page/n34/mode/1up
- ↑ https://www.4corn.co.uk/articles/websites/clanhtml/RPC.html
- ↑ http://hw-museum.cz/mb/6/abit-bp6
- ↑ http://chrisacorns.computinghistory.org.uk/32bit_UpgradesA2G/Acorn_ARM6102ndProc.html
- ↑ http://chrisacorns.computinghistory.org.uk/32bit_UpgradesH2Z/Simtec_Hydra.html
- ↑ http://www.simtec.co.uk/products/AUHYDRA/gallery.html
- ↑ https://archive.org/stream/AcornUser162-Dec95#page/n7/mode/2up
- ↑ http://chrisacorns.computinghistory.org.uk/32bit_UpgradesA2G/ACE_ARMSwitcher.html
- ↑ http://www.john-ward.org.uk/personal/john/computers/html/rocket.html
- ↑ http://www.computinghistory.org.uk/det/44052/RISC-PC-Pizza-Oven/
- ↑ https://www.arcsite.de/magazin/sonst/acorngeschichte/index.html
- ↑ https://farm9.static.flickr.com/8164/7575489832_66e7d05a71_b.jpg
- ↑ https://farm9.static.flickr.com/8007/7575486988_9517e6e486_b.jpg
- ↑ https://www.4corn.co.uk/articles/phoebe/
- ↑ http://qubeserver.com/qube/systems/images/KineticRPC/KRPCCPUs.jpg
- ↑ http://www.iconbar.com/forums/viewthread.php?newsid=918
- ↑ http://www.computinghistory.org.uk/det/35676/Iyonix-PC/
- ↑ https://web.archive.org/web/20050907153423/http://www.md-omega.de/
- ↑ http://www.advantage6.com/products/A9home.html
- ↑ http://a4com.de/riscos/a9home/a9h.htm
- ↑ http://a4com.de/riscos/bik.htm
- ↑ a b http://www.armini.co.uk/
- ↑ http://a4com.de/riscos/pik.htm
- ↑ http://www.dorchester3d.com/printing/blog/2016/06/raspberry-pi-acorn-risc-os-case
- ↑ https://riscos.fr/utilisez.html
- ↑ http://www.elesar.co.uk/
- ↑ https://www.raspberrypi.org/blog/risc-os-for-raspberry-pi/
- ↑ https://www.riscosopen.org/content/downloads/raspberry-pi
