Acorn computers are a British built line of computers that started with 6502 based machines and now are based on ARM processors. Oddly enough Acorn computers are made by the Acorn Computer Group ( see http://www.acorn.com/ for more details.) Section 1.2 details those machines currently in manufacture and how to fetch a full list of all machines known to have been made by Acorn. Acorn machines are known for their innovation, flexibility and reliability of hardware/software.
From January 1999 Acorn Computers Ltd., has been renamed Element-14, focussing more on their Digital TV technology. More information is available from http://www.element-14.com
Reading through section 1 should give newcomers to the Acorn scene a reasonable appreciation of what the machines can do by default. They were fairly strong in education and it was Acorn's primary market, although the Acorn group of companies are making moves into other markets and have consolidated primarily on the Digital TV market for the future. For those people who wish to see RISC OS in typical use then visiting http://www.geocities.com/~banksp/Power/Acorn/RISCOS.html will provide you with some images and text about using RISC OS.
The full list of Acorn made machines is somewhat lengthy now and are
mostly no longer in manufacture. Accordingly this list distributed in the
FAQ includes only Archimedes/ARM based machines, which are those currently
manufactured by Acorn. A full
list is maintained on Philip Banks email server under the filename
'MachineLst'. (see question
7.4 for how to use his email server.) This is, as far as I am aware, a
complete list of all Acorn machines made with the possible exception of the
latest machines for which I have yet to get the detailed specifications.
This is the next generation and architecture of machines - superseding, but compatible with, the Archimedes range of machines. All of them feature a highly configurable and modular system that makes a bewildering variety of options available. All are founded on the 'second generation' chipset featuring VIDC20, IOMD and the newer ARM6, and better, cell processors. This new range was launched on the 15th of April 1994 with the RiscPC 600 series of machines.
The new machines feature the processor card option, the concept of which was first shown in the A540 as well as a unique second processor slot allowing the machines to have two processors in the system, at once, of radically different types. Simply by slipping a 486 chip in, on an appropriate board of course, Intel based software can be run on the machine adjacent to native ARM programs. Both processors share the system resources and can be allocated memory and the like to use. Memory management has been improved with memory paging always being done in 4K pages.
Further more the podule interface has been extended with DMA to and from podules, extended addressing, 32bit data pathways from the IO system as well as a vastly expanded memory map for each podule. Realtime video from the IO system becomes a reality with high speed and data transfer applications being boosted considerably. These machines are to be the ones to carry Acorn for the next three to six years and look set to do so nicely.
Launched 12th of July 1995.
RiscPC 700 4M HD425 4096Kb Advanced Disc Filing System by default with a High Density drive. IDE interface by default. (425 Mb.) ARM710 processor. (40 MHz) 16 MHz RAM. 4096k OS in ROM. ~32 MIPS. (Arbitrary estimate.) RiscPC 700 9M HD425 4096Kb (1 Mb of VRAM) Advanced Disc Filing System by default with a High Density drive. IDE interface by default. (425 Mb.) ARM710 processor. (40 MHz) 16 MHz RAM. 4096k OS in ROM. ~32 MIPS. (Arbitrary estimate.) RiscPC 700 10M HD850 8192Kb (2 Mb of VRAM) Advanced Disc Filing System by default with a High Density drive. IDE interface by default. (850 Mb.) ARM710 processor. (40 MHz) 16 MHz RAM. 4096k OS in ROM. ~32 MIPS. (Arbitrary estimate.)
Acorn, around October 1995, restructured itself into separate companies. Consequently the originating company will be noted by the machine model name, in brackets, from here on down.
4096k Memory (expandable to 16384kb) IP Stack by default, capable of using extra drives as required. Smartcard interface by default. ARM 7500FE processor. (40 MHz) 12 MHz RAM. 4096k OS in ROM. ~35.9 MIPS.
2048k Memory (expandable to 32768kb) CDFS by default. Optional CDROM drive. ARM 7500FE processor. (32 MHz) 12 MHz RAM. 4096k OS in ROM. ~28.7 MIPS.
The design has been available since mid 1996.
8192Kb Memory (expandable to 256Mb) ADFS by default. IDE interface. (425 Mb) ARM 7500 processor. (32 MHz) 12 MHz RAM. 4096k OS in ROM. ~29 MIPS.
Available since Mid 1996.
8192Kb Memory (expandable to 256Mb) ADFS by default. IDE interface. (420 Mb) ARM 7500 processor. (40 MHz) 12 MHz RAM. 4096k OS in ROM. ~35.9 MIPS.
As part of an image strengthening procedure Acorn have reconsolidated to present one company image to the world. Consequently I won't be marking which subdivision 'makes' the machine anymore - all machines are 'Acorn' machines now.
Launched 18th of May 1997 at the Wakefield Show.
8192Kb EDO Memory (expandable up to 136Mb) ADFS by default. IDE interface. (1.2 Gb hard drive) ARM 7500 FE processor. (48 MHz) 32 MHz RAM. 4096k OS in ROM. ~43.08 MIPS.
Launched 7th October 1997.
4096k Memory. (Expandable to 256 Mb, comes with 2 Mb VRAM as well) IP Stack by default, capable of using extra drives as required. Smartcard interface by default. Digital SA110 processor. (233 MHz) 16 MHz RAM. 8192k OS in ROM. ~233 MIPS.
The details of all current ARM chips and their capabilities are contained within a file stored on Philip Banks email server, the filename is 'ARMChips'. See question 7.4 for how to request this file.
This information is now contained on Philip Banks email server. If you wish to know the 'new' features of RO3 over RO2 then send a request to his email server, as detailed at the start of the FAQ, for the filename 'RO3diffs'.
Quite a few, although nothing particularly drastic OS wise, mostly
improvements although the lifting of the FileCore partition limit and the
incorporation of JPEG handling into the OS are quite substantial improvements.
Here is the list :-
Like RISC OS 3.6, RISC OS 3.7 is primarily changed behind the scenes and is an incremental improvement of the OS. The changes mostly have been geared towards rendering the OS StrongARM compatible. Here is the list :-
RISC OS 3.8 was a developmental version of RISC OS 4 released to developers just before the closure of Acorn's Workstation division and cancellation of the Phoebe project. It has now been completed by the newly formed RISC OS Ltd and RISC OS 4 is the first new version of RISC OS to be released by a company other than Acorn, A comprehensive list of features was released onto their own web site during April 1999. This can be obtained from http://www.riscos.com/Features.html
In a nutshell some of the major new features are:-
All the Acorn machines are highly upgradeable so that they can achieve colour depths and resolutions beyond what is listed here. What is listed here is the default capabilities of the machines as supplied by Acorn. As such it should be taken as a guide to the minimum abilities of the hardware.
X res. Y res. Colours 640 256 2 320 256 2,4 160 256 4,16As well a Teletext character graphics mode and two text only modes were provided by default. The palette range was 16 colours with modes using less than 16 colours capable choosing any mix of the 16 colours, up to the number displayable of course, for display.
X res. Y res. Colours 160 256 4,16,256 320 256 2,4,16,256 640 250 4,16 640 256 2,4,16,256 640 480 2,4,16,256 640 512 2,4,16,256 1056 250 16 1056 256 16,256 1152 896 2As can be seen this quite a wide variety of default screen modes. Most are provided to allow driving the various kinds of monitors out there easier, since they are suited to that monitor. The palette range was 4096 colours (12 bit) but the VIDC1a only had 16 hardware palette registers. This meant that in screen modes with sixteen colours or less then the colours could be mapped to any of the 4096 available. However in 256 colour modes 4bits of the colour data are hardware derived and cannot be adjusted. The net result was in a 256 colour a block of 16 colours could be assigned as desired with that block of 16 covering a range of the 4096 available colours.
X res. Y res. Colours 160 256 4,16,256 320 256 2,4,16,256 640 200 2,4,16,256 640 250 16 640 256 2,4,16,256 640 352 2,4,16,256 640 480 2,4,16,256 640 512 2,4,16,256 768 288 2,4,16,256 800 600 2,4,16 896 352 2,4,16,256 1056 250 16 1056 256 16,256 1152 896 2Because the display hardware was essentially the same as the 8MHz machines' the palette handling was identical.
X res. Y res. Colours 160 256 4,16,256 320 256 2,4,16,256 640 200 2,4,16,256 640 250 4,16 640 256 2,4,16,256 640 352 2,4,16,256 640 480 2,4,16,256 640 512 2,4,16,256 768 288 2,4,16,256 800 600 2,4,16,256,32k*,16M** 896 352 2,4,16,256 1024 768 16,256*,32k** 1056 250 16 1056 256 16,256 1152 896 2 1280 1024 4,16*,256** 1600 1200 16*,256** * Requires 1 MB of VRAM ** Requires 2 MB of VRAMWith the addition of Video RAM (VRAM) to the Risc PC the base capabilities are a touch variable, thus the note next to some of entries. All other modes are available with standard DRAM, and these the only modes the A7000 can access. The A7000+, thanks to it's faster memory speeds, functions equivalently to a RiscPC with 1 Mb of VRAM even though it doesn't have any VRAM itself.
Furthermore the new VIDC20 has 256 palette registers, compared to the VIDC1a's 16, and a palette range of 16 million colours. Exactly how the colour mapping in 32,000 modes is handled is not yet clear. Again these are just standard screen modes provided, and even perhaps not all of them - the Risc PC is completely configurable in display resolutions and capabilities.
However each monitor type must have a mode definition file set up for
it, to allow you to take advantage of this flexability. A library of
common monitor definition files can be found at :-
http://acorn.cybervillage.co.uk/mdf.htm
It must be stressed again that these are merely the resolutions and colour depths defined by the machines operating systems. In all of the machines cases there are both hardware and software extensions that alter and increase the list.
Short answer, full VM is not possible under the current versions of RISC OS. The problem is that most of RISC OS works in SVC mode, if a DataFetch abort occurs then R14_svc is corrupted. This makes returning from the SWI somewhat problematic. This is a hardware limitation with the ARM2 and ARM3 cell chips. Hardware using ARM6 or better processor cells have special memory abort modes that alleviate this problem so future machines and incarnations of RISC OS may well have VM available. Indeed the new RiscPC machines make prime candidates for having virtual memory, however there are still re-entrancy issues that make this problematic for RISC OS. (Consider loading data from a file into paged out virtual memory...)
However limited solutions are available now. !Virtual is one such solution allowing VM for a user process using a limited subset of SWI's that are carefully 'protected' against R14_svc being corrupted. Such solutions suffer from the restricted set of SWI's they support and are mostly useful for batch style processing jobs like compilation or memory intensive processing jobs. !Virtual currently does not work with Risc PCs due to the fact that it requires a page size which is a multiple of 8kb. (This means !Virtual will not work with A305s.)
Also available commercially, from Clares Micro Supplies, is Virtualise for the RiscPC machines. This provides virtual memory on dynamic areas. As more and more software starts to use dynamic areas for data storage and manipulation this will become increasingly useful.
Due to the rapid development of Linux exact details about the latest incarnation of Linux are not kept in this FAQ. However for the latest information you might like to consult these web pages, or email the people involved with the port :-
Native Linux page :-
http://www.arm.uk.linux.org/~rmk/armlinux.html (rmk@ecs.soton.ac.uk)
PC card Linux :-
http://www.ph.kcl.ac.uk/~amb/linux.html (amb@physig.ph.kcl.ac.uk)
If you have the Acorn Clan disc and would like to install ArmLinux, I have written a Dummies Guide to Installing ArmLinux which is available at http://www.vigay.com/riscos/linux.html
It has been a long tradition with Acorn OSes to have hidden sections that give credit to the people involved in the creation of that OS. The BBC Model B ROMs had the names of the people involved hidden in the memory space occupied by Fred, Jim and Shelia. With the release of the ARM powered machines this tradition has continued on.
REM Extract Names and Pictures from RISC OS 3.50, 3.60 and 3.70 ROMs REM REM Based on an original program (for RISC OS 3.50) by Nick Craig-Wood. REM Updated by Matt Rix <BigRISC@CyberJunkie.Com> SYS "OS_Byte",129,0,255 TO ,version% CASE version% OF WHEN &A5: S=&1F47AC :REM RISC OS 3.50 WHEN &A6: S=&358F18 :REM RISC OS 3.60 - Thanks to Terry Adams for finding this WHEN &A7: S=&3A0868 :REM RISC OS 3.70 OTHERWISE: ERROR 0,"Cannot run on this ROM version.":END ENDCASE S+=&3800000 E=S+&3130 O=65536 SYS "Squash_Decompress",%1000,-1 TO Q DIM R Q,P O SYS "Squash_Decompress",%0100,R,S,E-S,P,O TO,,,,,U path$="Pipe:$." piccy$=path$+"Pictures" names$=path$+"Names" run$="Filer_Run " SYS "OS_File",10,piccy$,&FF9,,P+8,P+P!4+8 SYS "OS_File",10,names$,&FFF,,P+P!4+8,P+O-U OSCLI "SetType "+piccy$+" Sprite" OSCLI "SetType "+names$+" Text" OSCLI run$+piccy$ OSCLI run$+names$ END
Due to the rapid development of RiscBSD exact details about the latest
incarnation of it are not kept in this FAQ. RiscBSD being a port of NetBSD,
a Unix variant, to the RiscPC. However for the latest information you might
like to consult these web pages, listen to the RiscBSD email list or email the
people involved with development of it :-
Risc BSD page :-
http://www.ph.kcl.ac.uk/~amb/riscbsd/ (amb@physig.ph.kcl.ac.uk)
RiscBSD email list :-
listserver@ic.ac.uk place "subscribe riscbsd <RealName>" in the message body.