When the RiscPC was released, in May 1994, the following details comprised its technical overview and base specification:
Like its predecessor the ARM 3, the ARM610 is designed by Advanced RISC Machines (ARM) Limited and is a 32-bit RISC CPU with a 4 KB cache. The new processor gives the Acorn Risc PC exceptional performance, particularly in full-colour modes (when fitted with VRAM). For example, it is approximately twice as fast as the Acorn A5000 in 16 colour VGA mode.
Future upgradeability is guaranteed as faster versions of the ARM 600 and future generations of the ARM700 (Q4 1994) and ARM800 will be available for use in the Acorn RISC family for seamless migration.
Risc PC can address up to 256MB of memory, and although current technology limits its physical memory to 128MB using commercially available DRAM, the Risc PC has more than enough RAM to load and manipulate the largest full-colour images and combine them with text, graphics, video and sound. Risc PC also supports up to 2MB of VRAM.
The Risc PC's open architecture makes it possible to fit a second processor to the computer, sharing all the memory, input and output facilities of the main ARM610 processor. This represents a tremendous cost advantage over traditional processors mounted on an expansion card, which often required memory to be duplicated. Any processor may be used, provided its card contains all necessary arbitration logic.
The first of these second processors to be offered on the Risc PC will be a 25/33 Mhz 486SX PC card including DOS and Windows. With a PC Card fitted, the Risc PC will behave just like an ordinary 486 PC with Windows and a graphics accelerator offering SVGA video (800 by 600 with 16 million colours).
A special Application Specific IC (ASIC) is currently being developed embodying all the speed dependent PC logic. Performance will be further enhanced by an optional 32KB or 128KB secondary cache on the processor chip, which will be managed by a cache controller included in the ASIC.
It is expected that even higher performance PC cards, using the P24T type Pentium processors, will soon be introduced. Other uses of the dual processor capability are also being planned by independent developers.
The Risc PC can take two single-width expansion cards in its standard configuration, plus two more for every centre-section added to the system. The DEBI bus also supports Direct Memory Access (DMA), so data can be read from and written to system RAM by expansion cards, without interrupting the CPU.
The new DEBI bus makes it possible to implement even higher performance expansion cards handling large amounts of data, such as video-capture and direct-drive printer cards, which can have substantial on-card buffer memory, directly addressable to the ARM processor.
Acorn has consistently been a pioneer in the development of multimedia, from the earliest days of the BBC Micro, with sound, colour and graphics, to the latest innovations in full motion video and in the natural integration of CD-ROM technology with computers. As described above, every Risc PC comes with full 24-bit colour capability; the support for up to 256MB RAM and 2MB of VRAM; and a large hard disk (minimum of 210MB). Stereo sound and video playback are also standard. An integral CD-ROM drive providing Photo CD support is also available as an added option. This all makes the new Risc PC the ideal choice for multimedia applications.
The Risc PC has eight channels of stereo sound as standard and has a built-in speaker and stereo headphones socket. This is complemented by Acorn Replay—Acorn's full motion video system. A world leader, Acorn Replay has made it possible for thousands of users to put together multimedia publications on Acorn computers at low cost. Acorn Replay's playback software, ARPlayer, is included with every Risc PC, together with a number of movies demonstrating the capabilities of Acorn Replay.
Acorn's heritage in multimedia means a strong base of multimedia authoring applications already exist. These enable the user to combine video, audio, text and images in hypertext-linked documents which can be designed for interactive training, reference and project work.
The preferred means of networking is Ethernet and Acorn supports both thick and thin media. Additional multi-session cards will enable one or more protocol stacks (e.g. TCP/IP and IPX) to be run simultaneously regardless of the type of media. The use of industry standards enables Acorn users to run mixed network environments with different types of machines where they are running standard software.
The Risc PC offers a choice of up to 16 million colours and up to 1600 by 1200 resolution. Industry standard TIFF and JPEG 24-bit colour images can be loaded into the Risc PC, decompressed on the fly and displayed as RISC OS bit image files.
Made possible by a new ARM VIDC20 video chip, a new colour picker or palette allows the user to work in one of the three colour modes - RGB, CMYK and HSV.
The Risc PC has an empty 5.25" drive bay, ready to receive an optional CD-ROM, providing an integrated, neat CD-ROM solution. Both RISC OS and (using a PC card) DOS CD-ROMs can be used. Acorn Replay movies can be played from CD-ROM, and (subject to copyright) images copied from both RISC OS and DOS format disc, translated into sprites, edited and used in RISC OS applications.
The optional CD-ROM drive enables the user to read Kodak Photo CD-format discs, while the video performance of the Risc PC ensures that none of the original picture quality is lost. Once displayed on the computer, PhotoCD images can be edited and dropped into multimedia publications.
The Acorn Risc PC range features an innovative case design. Leading design house Cambridge Product Design has combined contemporary styling and ergonomics to produce a product that is both aesthetically pleasing and practical. Constructed in a high-impact-resistant plastic, which is usually used in the manufacture of visors and riot shields, the case is robust and hard wearing. To cut down electrical emissions, the inside has been metal sprayed.
The case's modular construction makes upgrading simple as the Risc PC can be taken apart in seconds without any tools. The Risc PC supports an almost limitless range of configurations and upgrades (memory, disc drives, CD-ROM drives, expansion cards, network cards and even additional processors) and therefore this ease of access is important.
The base system contains a 3.5" floppy disk drive, a hard disk (at least 210 MB), one vacant bay for a 5.25" device (e.g. CD-ROM), two available expansion slots and a space for a networking card. Each additional system layer, or 'slice', enables the user to add an additional 3.5" device, a 5.25" device and two more expansion cards. Up to six additional slices can be added in total (the maximum number of expansion cards per system is eight.) Adding extra devices or cards is achieved very simply. Cards are slotted directly into the back of the computer; network cards and additional 3.5" or 5.25" devices involve simply removing the lid and plugging in.
The AKF60 Super VGA 14" monitor is included as standard with all initial Risc PC confirgurations. As an option, users of any of the Risc PC models can upgrade to an AKF85 17" monitor. The AKF85 will provide a high quality alternative monitor for users needing up to 1600 by 1200 resolution.
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