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Comp.Sys.Acorn FAQ List. Last alterations 13/Nov/1994 ===================================================== ---------------------------------------------------------------------------- Recent alterations :- Section 2.7 added. Section 7.5 added. ---------------------------------------------------------------------------- Contained below is a list of the most commonly asked questions about Acorn machines in comp.sys.acorn. Before posting to comp.sys.acorn, if you are new to the group, check to see if your question(s) are already answered below. Corrections and/or additions to the list can be emailed to :- banks_p@kosmos.wcc.govt.nz And I'll try to add them as soon as possible.... This FAQ is posted bi-weekly to comp.sys.acorn, comp.sys.acorn.announce and news.answers. The posted sections of the FAQ is available from an email server at MIT. To request the FAQ from this server send an email to mail-server@rtfm.mit.edu. No subject is needed and the body should be :- send /pub/usenet/news.answers/acorn/faq Also the FAQ itself and sub-sections of it are stored in an email server I personally run. See section 7.4 for further details on how to access this email server. Lastly this list is copyright to Philip R. Banks but permission is granted for free distribution of the entire list or quoted segments of it. If you wish to include segments of the list into other documents then proper attribution must be performed and if you wish to include and part of the list, or the list in full, in any commercial product then express permission must be obtained from myself. Index of Questions. =================== The questions have been catagorised loosely into related sections, in an effort to make finding the desired information simpler and quicker. Section 1: Acorn Hardware and Operating Systems. ------------------------------------------------ 1.1) What kind of Acorn machines are there? 1.2) What versions of the processor are there and what are their capabilities? 1.3) What are the main new features of RISC OS 3? 1.4) What are the differences between RISC OS 3.5 and RISC OS 3.11 & 3.10? 1.5) How compatible with other systems is an Acorn machine? 1.6) What are the graphics capabilities of the Acorn machines? 1.7) Is Virtual Memory possible under RISC OS? Section 2: Upgrades and Expansion. ---------------------------------- 2.1) What are the memory limits of the various Acorn machines? 2.2) What is a second processor and what second processors are there? 2.3) Can PC VGA Monitors be added to an Acorn machine? 2.4) Are there any cards for IBM PC or compatible machines that Acorn have produced? 2.5) What is a VIDC enhancer? Will I need one for my new multisync monitor? 2.6) What configuration of serial cable should I use on my machine for modem work? 2.7) How can I get unfiltered sound from an Acorn machine? Section 3: Configuration. ------------------------- 3.1) What is ADFSBuffers and what is the best setting for it? 3.2) How do I enable solid drags in RISC OS 3? Section 4: Hardware problems. ----------------------------- 4.1) My hard drive gives me disc errors when I use, what do the error numbers mean? 4.2) My disc gives me a 'Broken Directory' or my Free Space Map is corrupt, what can I do? 4.3) What does the power on self-test check and how does it signal errors back to you? 4.4) My Real Time Clock has paused, how do I restart it? Section 5: Software Issues. --------------------------- 5.1) When using DOS discs I often find the last parts of files haven't been written correctly, what am I doing wrong? 5.2) I have obtained [PD] program X but find it needs [version Y.YY of] module Z, which I don't have. Where can I get it? 5.3) What is the current File-type allocation ranges and why won't Acorn provide a full file-type list? 5.4) Is there a Modula 2 compiler for the Arc? 5.5) What version of module X can I assume that all users have? 5.6) What's the minimum version of module X that my program needs? What features were introduced/what bugs were fixed in which versions? Section 6: Viruses. ------------------- 6.1) How can I protect against viruses? 6.2) Where can I obtain !Killer? Section 7: Net resources. ------------------------- 7.1) What archives/FTP sites are available? 7.2) What Acorn related companies are available on the net via email? 7.3) Why have there been no postings to comp.{binaries,sources}.acorn recently? 7.4) How to retreive the FAQ from the source... { Or how to use my email server. } 7.5) What WWW pages are out there for Acorn topics? ---------------------------------------------------------------------------- Section 1: Acorn Hardware and Operating Systems ---------------------------------------------------------------------------- 1.1) What kind of Acorn machines are there? 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 the currently manufactured by Acorn. A full list is maintained in my email server under the filename 'MachineLst'. 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. A4 - Acorns first portable machine. The A4 is functionally an A5000 in portable form. Featuring power save modes, an LCD screen and software configuration of the power saving features it was released July 1992. It is called the A4 because it's footprint on a desk is apparently that of an A4 piece of paper. 2048k Memory Advanced Disc Filing System by default with High Density drives. ARM 3 processor. (24 MHz normally, 6 MHz in power save mode.) 12 MHz RAM. (3 MHz in power save mode.) 2048k OS in ROM. ~13.25 MIPS. A30x0 - Two models of this machine exist the A3010 and the A3020. Both are designed as low end 'family solution' machines. They are also among the first machines to feature the ARM250 processor offering improved performance over an ARM2 (but less than an ARM3) and are designed to supplement the A3000 machine as a low cost entry machine into the Acorn world. Its other main claim to fame is it is the first Archimedes series machine that features joystick ports (only in 3010 model, the 3020 has a network connector instead.). Launched August 27th 1992. 1024k Memory Advanced Disc Filing System by default with High Density drives. IDE 60 Mb Hard Drive (only in A3020 with HD option). ARM 250 processor 12 MHz RAM. 2048k OS in ROM. ~7.2 MIPS A4000 - This is a higher end more expandable version of the A30x0 series machines and is in a three box format similar to the A5000. It also is driven by an ARM 250 processor however it features over the A30x0 machines optional Ethernet & Econet ports, a high density floppy drive and an 80Mb IDE drive by default. The aim of this machine is strongly towards the home office and more 'serious' applications than the A30x0 series. Launched August 27th 1992. 2048k Memory Advanced Disc Filing System by default with High Density drives. IDE 80 Mb Hard Drive by default. ARM 250 processor 12 MHz RAM. 2048k OS in ROM. ~7.2 MIPS A5000 (alpha variant) - This is an improved variant on the A5000 featuring a considerably faster processor, 33 MHz, with the ability to have a similarly clocked FPA unit installed. It also features a considerably larger base hard drive size of 160 Mb on the 4 Mb model, the lower 2 Mb model still as an 80 Mb drive. Finally it has improved alterations to it allowing easy expansion of the machine to 8 Mb of memory by default. (IE without having to use third party solutions.) Released 10th September 1993. 2048k Memory Advanced Disc Filing System by default with High Density drives. IDE interface by default. ARM 3 processor. (33 MHz) 12 MHz RAM. 2048k OS in ROM. ~16.96 MIPS. Acorn Risc PC series This is the next generation and architecture of machines - superceding, 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 4Kb 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. Real-time video from the IO system becomes a reality with high speed and data transfers 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. RiscPC 600 2M HD210 2048Kb Memory. (No VRAM) Advanced Disc Filing System by default with a High Density drive. IDE interface by default. (210 Mb.) ARM 610 processor (30 MHz) 16 MHz RAM. 2048k OS in ROM. ~26 MIPS. (Arbitrary estimate.) RiscPC 600 5M HD210 4096Kb Memory. (1Mb of VRAM) Advanced Disc Filing System by default with a High Density drive. IDE interface by default. (210 Mb.) ARM 610 processor (30 MHz) 16 MHz RAM. 2048k OS in ROM. ~26 MIPS. (Arbitrary estimate.) RiscPC 600 9M HD420 8192Kb Memory. (1Mb of VRAM) Advanced Disc Filing System by default with a High Density drive. IDE interface by default. (420 Mb.) ARM 610 processor (30 MHz) 16 MHz RAM. 2048k OS in ROM. ~26 MIPS. (Arbitrary estimate.) ---------------------------------------------------------------------------- 1.2) What versions of the processor are there and what are their capabilities? The details of all current ARM chips and their capabilities are contained within a file stored in my email server, the filename is 'ARMChips'. See the instructions near the end of the FAQ for requesting this file. ---------------------------------------------------------------------------- 1.3) What are the main new features of RISC OS 3? This information is now contained in my email server. If you wish to know the 'new' features of RO3 over RO2 then send a request to my email server, as detailed at the start of the FAQ, for the filename 'RO3diffs'. ---------------------------------------------------------------------------- 1.4) What are the differences between RISC OS 3.5 and RISC OS 3.11 & 3.10? There are alot of behind the scenes differences but the most obvious changes are :- -The system font has been replaced by an outline font. -The Filer uses solid drag icons, including a 'package' icon for multiple file drags. -Error dialogue boxes can now have a button for requesting interactive help on the error. -Windows can have textured backgrounds by default. (This feature can be used independantly of the application supporting it.) -Applications can have up to 28Mb of memory apiece, if available. -The Palette utility has been replaced by the Display Manager, offering an alternative method of choosing screen modes from the older mode number method. -The Task Manager allocates memory via logarithmicly scaled slider bars. -Rogue tasks can be stopped, or killed, by pressing Alt-Break. -The CMOS & hard drive can be protected from alteration. Also, due to the new hardware, there are alot of behind the scenes extensions to the OS including the provision of new dynamic areas, extended podule support, hard drive locking and a wealth of other features. ---------------------------------------------------------------------------- 1.5) How compatible with other systems is an Acorn machine? PC :- The Archimedes can handle DOS discs (720k; the A5000 and later models can also handle 1.44M floppies). In RO3, this is built in, under RO2 you have to use one of the (PD) utilities. There are two PC (software) emulators that can handle most PC software, three if you count the fact that Acorn's offering is split into two emulator programs. There are also PC cards, containing an 80x86 processor and other PC hardware, which uses the Archimedes' disc and video. All emulators are multitasking (and not PD). RiscPC machines, by adding a 486 processor card, can fully emulate a PC. Unix :- Unix software can be ported (and in fact many packages already have been) with the help of UnixLib, which is PD. Memory-hungry ports, such as gcc, can be run with the aid of !Virtual (also PD). Of course if your really desperate to run Unix software it might be advisable to buy RISCiX, the Acorn flavour of Unix. Mac :- Software has been released that reads Macintosh High Density discs and there is some out there which claims to read the low density ones as well (I have yet to verify this personally though) so that the shifting of files to and from a Macintosh is possible. Also most modern Macintoshs can, like Acorn machines, read and write PC format discs so transfer is possible via that medium as well. There is no Mac emulator available. Atari ST :- Like PC floppies, the Archimedes can read, write and format ST-format floppies. No emulator for the ST is known. Amiga :- The amiga uses an unusual disc format that is not easily read by other machines. Accordingly there is currently no Amiga format disc reader available. But Amiga's can read PC discs, so again transfers can occur via that medium. There is no Amiga emulator. Spectrum :- There are emulators around for this and Amstrad, the owners of the Sinclair copyright, have released permission for the ROM images, needed to run these emulators, to be copied and released with the emulators. Apple][ :- Again emulators are available for this. However they, like the Spectrum emulators, require a copy of the ROM image to work. The copyright of the ROM image for these machines, as far as I am aware, prevents them being distributed, so you have to source your own copy of it. ---------------------------------------------------------------------------- 1.6) What are the graphics capabilities of the Acorn machines? All the Acorn machines are highly upgradable 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. 8 bit machines. This covers the BBC Model B, BBC Model B+, Master 128 and ABC range of machines. The display hardware was based on the 6845CRTC chip and was highly flexible for it's time. Resolutions possible :- X res. Y res. Colours 640 256 2 320 256 2,4 160 256 4,16 As 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. 8 MHz ARM based machines. This is the original Archimedes range of machines and covers the A300 series, A400 series, R140 and A3000 machines. The increased capability of the VIDC1a chip dramatically enhanced the resolutions and colours depths possible, namely :- 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 2 As 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. 12 MHz ARM based machines. This covers the A3010, A3020, A4000, A4, A500, A540 & R260 machines. Here the VIDC1a was still used but it had an extra oscillators added and the primary oscillator was faster (32 MHz) giving finer pixel resolutions. The extra oscillator provided true PC VGA style compatibility for monitors instead of a 24 MHz 'faked' version which sometimes caused problems with intolerant VGA monitors. 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 2 Because the display hardware was essentially the same as the 8MHz machines' the palette handling was identical. Risc PC machines. This covers all Risc PC in the Risc PC 600 series. Here the newer VIDC20 chip has been used and the display capabilities are somewhat extended. Namely :- 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 VRAM With 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. 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. 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. ---------------------------------------------------------------------------- 1.7) Is Virtual Memory possible under RISC OS? 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. Future 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 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. --------------------------------------------------------------------------- Section 2: Upgrades and Expansion. ---------------------------------------------------------------------------- 2.1) What are the memory limits of the various Acorn machines? For the most part the 8 bit machines were limited to a maximum of around 256k of memory. Although various expansion systems including second processors effectively meant the upper limit was about 1 Meg. (Although I have been told of a second processor with 4 Meg of memory in it. ) For the early 32 bit machines *the* upper limit currently is 16 Meg of memory. Not all of the range of machines are capable of this however and the list looks something like this :- A3xx - 8 Mb maximum through third party, 1 Mb official limit. A4xx - 8 Mb maximum through third party, 4 Mb official limit. A4xx/I - 8 Mb maximum through third party, 4 Mb official limit. A3000 - 4 Mb maximum through third party, 2 Mb official limit. A540 - 16 Mb maximum. A5000 - 8 Mb maximum through third party, 4 Mb official limit. A4 - 4 Mb official limit. A30x0 - 4 Mb official limit. A4000 - 4 Mb official limit. A5000 - 8 Mb official limit. (alpha variant of the A5000) Newer RiscPC machines have an official upper limit of 256 Mb, plus 2 Mb of VRAM, on all models. However this does require you using 128 Mb SIMMS which are currently not very common... ---------------------------------------------------------------------------- 2.2) What is a second processor and what second processors are there? A second processor was the generic name for a range of parasite processors that could be linked to Acorn's 8 bit machines via what was called the `Tube` interface. Basically the host machine became dedicated to handling the Input and Output while the second processor would do the higher level functions (like running your programs). The second processor ran asyncronously to the host processor allowing incredible increases in execution speed for programs. A wide range of processors were supported this way allowing Acorn's eight bit range of machines to remain viable and useful for much longer than their technology would suggest. The Second Processors that existed are :- Z80 second processor. 6 MHz RAM. 64k Memory. CP/M OS. External second processor for all eight bit machines. 6502 second processor. 3 MHz RAM. 64k Memory. Extended version of the BBC MOS. External processor for all eight bit machines. 32016 second processor. 6 MHz RAM. 256k-4096k Memory. Panos. External processor for all eight bit machines. ARM 2 second processor. 8 MHz RAM. (At a guess...) 4096k Memory. Brazil OS. External processor for all eight bit machines. 6502 co-processor. (internal second processor). 4 MHz RAM. 64k Memory. Extended version of BBC MOS. Internal processor for Master 128 machines but could be fitted external to the other eight bit machines. 80186 co-processor. 10 MHz RAM. 512k Memory. DR-DOS+ with GEM. Internal processor for Master 128 machines but could be fitted external to the other eight bit machines. ---------------------------------------------------------------------------- 2.3) Can PC VGA Monitors be added to an Acorn machine? It depends on what monitor you have, and what Acorn machine you have. There are two main types of PC VGA monitors out there... 1) Fixed Frequency These monitors will only display video signals with certain line and refresh rates. They will typically only display CGA / EGA / VGA modes. 2) Multi Frequency These monitors will display any video signal within a certain range, typically 30-50Khz line rate and 50-80Hz refresh rate. Type 1 almost always require separate syncs as the monitor uses the polarity of the syncs (mainly positive going negative or mainly negative going positive) to determine what the line and refresh rate should be. Type 2 vary. Some require seperate syncs (vertical and horizontal) and others will work with composite syncs (vertical and horizontal EOR together). As PC monitors typically start at a line rate of 30Khz compared to the TV broadcast modes (mode 12 etc.) that have a line rate of 15Khz, VIDC has to do more work to obtain a 30Khz line rate. This means that you computer will slow down silghtly if you use a 30Khz+ line rate monitor. If you have an ARM 3 fitted such slow downs will probably be negligible. Now, depending on what type of Archimedes you have depends on what type of monitor you can use. A540 / A5000 / A4 / A3010 / A3020 /A4000 Has software control over the polarity of the syncs and what frequency VIDC is clocked at. The A540 with RISC OS 2 can only use modes 26-28 (640x480) and 31 (800x600). However, by changing links and a *configure option, you can get the computer to generate seperate syncs with no problem. The other machines with RISC OS 3 can do even better. If you tell the computer that you have a VGA monitor it will re-map all of the 15Khz line rate modes up to 30KHz line rate. This means that you can play your games that require mode 12 / 13. However, as a PC monitor is designed to display 320 lines minimum then you will get a 'letterbox' effect as mode 12 has only 256 lines. All these machines have 24Mhz, 25.175Mhz and 36Mhz crystals to drive VIDC with. The 25.175Mhz crystal is needed to obtain the correct video rates for PC monitors displaying 640x480 screens. The 36Mhz crystal is used to obtain higher resolution modes, like 800x600x16 colours. A3000 This can generate seperate syncs but requires links to be set to determine the polarity. It has only a 24Mhz crystal and can therefore only drive 'forgiving' monitors correctly that don't mind the 640x480 video mode timings being slightly incorrect. The links to change, to set the sync polarity, are as follows: Link 24: Change from SOUTH to NORTH Link 25: Change from OPEN to CLOSED In order to obtain proper timings, and software control of the sync polarity, you will need a VGA VIDC Enhancer for the A3000. A400 series. The situation gets more complex. Due to an 'error' in the PCB / circuit diagram, the A400 series cannot generate seperate syncs satisfactorily. The video signal loses the green component when seperate syncs is selected. As standard, there is no polarity control over the syncs. In common with the A3000, there is only a 24Mhz crystal. If the PC monitor can handle composite syncs then the monitor can be used in 640x480 mode only. A300 series. Most, if not all, of the A300 series had the circuit board hardwired into composite mode continuously. There is only a 24Mhz crystal, and only composite PC VGA monitors can be used. RiscPC series. This has a *very* flexible VIDC in it and is quite capable of driving PC monitors with no trouble. However to connect an older machine (A3000,A300,400 series) to a VGA monitor, you will need a means of connecting the standard 15-pin VGA plug to the 9-pin socket in the computer. A number of companies sell 'converters', but all this boils down to is a lead with the following configuration :- .------------------------. VGA 15-pin socket \ 1 2 3 4 5 / \ 6 7 8 9 10 / \ 11 12 13 14 15 / '------------------' .------------------------. Arc 9-pin plug \ 1 2 3 4 5 / \ / \ 6 7 8 9 / '------------------' Signal VGA pin Arc pin Gnd 10 9 Red 1 1 Green 2 2 Blue 3 3 R gnd 6 6 G gnd 7 7 B gnd 8 8 H 13 4 V 14 5 In conclusion, apart from the A5000 and newer machines, no computer as standard can drive either a fixed frequency or multi-frequency PC monitor in all of the Archimedes modes satisfactorily. However VIDC enhancer boards can be bought to upgrade an Archimedes series machine to handle the needed timing and signals. ---------------------------------------------------------------------------- 2.4) Are there any cards for IBM PC or compatable machines that Acorn have produced? Yes. Three cards in total :- Springboard. ARM 2 processor. 4096k Memory. 8 MHz RAM. Brazil OS. PC ARM development system. Precursor to Springboard. Hardware functionally identical. Ecolink. An econet link card for the PC. ---------------------------------------------------------------------------- 2.5) What is a VIDC enhancer? Will I need one for my new multisync monitor? A VIDC enhancer is basically a clock change for your VIDC. Most Arcs (bar the A540 and newer machines) have 24 MHz VIDC chips installed in them. A VIDC enhancer increases this to 36 MHz allowing much higher resolution screen modes to be displayed on your Arc. (800x600x16 or SVGA standard becomes available.) You do *not* need one to use a Multisync monitor - the standard VIDC handles that just fine. However having a VIDC enhancer is only really useful if you do have a Multi-sync monitor. Note a VIDC enhancer is unneccesary and incompatible with the RiscPC range of machines. ---------------------------------------------------------------------------- 2.6) What configuration of serial cable should I use on my machine for modem work? Here follows a diagram of the necessary connections for common terminal programs to work properly. They are as far as I know the informal standard agreed upon by commercial comms software developers for the Arc. Pins 1, 4, and 8 must be connected together inside the 9 pin plug. This is to avoid the well known serial port chip bugs. The modem's DCD (Data Carrier Detect) signal has been rerouted to the Arc's RI (Ring Indicator) most modems broadcast a software RING signal anyway, and even then it's not really necessary to detect it for the modem to answer the call. Arc (9 pin) Modem (25 pin) ----------- -------------- +---1---DCD | | 2---RxD------------------------RxD----3 | | 3---TxD------------------------TxD----2 | +---4---DTR------------------------DTR---20 | | 5---0v-------------------------SG-----7 | | 6---DSR------------------------CTS----5 | | 7---RTS------------------------RTS----4 | +---8---CTS 9---RI-------------------------DCD----8 Of course you can connect the Modem pin 20 to any one of pins 1, 4, or 8 on the Archimedes plug, as they are all connected together anyway. Chocks Away Extra Missions (the flight simulator from 4th Dimension) suggests that the serial cable be wired as above except that pins 1-4-6 are connected together and the modem's CTS (pin 5) be connected to the Arc's pin 8 (ie the connections at pins 6 and 8 be swapped over at the Arc's end). This has been and it also seems to work fine. However newer Arc's like the A5000 have come out (and indeed the occasional A310) with a `corrected` serial port. This newer serial port operates as it should and is directly compatible with standard PC cables. Most comms software about at the moment does not take this in account and assumes that you have a cable patched in the manner described above. If you do not use such a patched cable on these `fixed` serial ports the software will generally fail to work. ---------------------------------------------------------------------------- 2.7) How can I get unfiltered sound from an Acorn machine? All Acorn machines are equipped with a sound filter designed to remove high frequency harmonics from the sound output. However this does cause a muffled feel to the sound as on some machines the filter is a little too excessive and it filters out valid frequencies. Also the filter is optimised for 20.833 kHz output and has less desirable results when the output rate is changed. Accordingly people who do audio work often want to bypass the filter. On all machines bar the A3000 there is the Internal Auxiliary Audio Connector (usually called link LK3), which can be easily plugged into to provide the unfiltered output. This connector has 10 pins on it and is usually found near the headphone socket on the motherboard. The pins are :- 1 Unfiltered Left 2 Ground 3 Filtered Left 4 Ground 5 Auxiliary Input 6 Ground 7 Filtered Right 8 Ground 9 Unfiltered Right 10 Ground Simply hook into the Unfiltered outputs. On an A3000 you need two 10uF 16V ALEC capacitors. Look for chip LM324 (IC39) and hook the capacitors like this :- Pin 1 --> --|+ |--- Unfiltered Left Pin 2 --> --|+ |--- Unfiltered Right The Risc PC & A400 machines have a connector similar to the A5000. There are several caveats to this procedure. Opening your machine may void your warranty and most definitely should not be attempted if you are unsure of the procedure. Do *not* unplug/plug the unfiltered audio output while the machine is turned on, by bypassing the filter you also bypass the normal protective circutry for the audio output. Finally you will hear higher harmonics present in the audio signal so you will need to connect the signal to a filter of somekind to reduce this extra noise. ---------------------------------------------------------------------------- Section 3: Configuration. ---------------------------------------------------------------------------- 3.1) What is ADFSBuffers and what is the best setting for it? ADFSBuffers are Read Ahead and Write Behind buffers for ADFS on your Archimedes. These are designed to improve the speed of filing operations by doing work at optimum times. There are some side effects of using them though. When active under RISC OS v2.00 and v2.01 discs *must* be dismounted before being removed from the floppy drive. Failure to do so results in the dreaded 'FileCore in use.' error. However if you are prepared to sacrifice the speed improvement they give configuring the buffers to 0 does remove this problem. (Or so I am informed.) Under RISC OS v3.00, as supplied with the early A5000 machines, these buffers generate a different problem and must *always* be configured off. Failure to do so results in spurious errors when using the Hard Drive on an early A5000. Symptoms include reformatting of crucial sectors of the disc, disc address errors and general failure to save files to the drive. So when using an A5000 with RISC OS 3.00 remember to configure them off! With RISC OS v3.10 all of the old problems have been cured with a new one introduced. Namely that if you have only a few ADFSBuffers configured and are accessing the floppy drive then your machine can occasionally lock up completely for you. It appears that any value of ADFSBuffers above 8 causes that problem to be largely alleviated (read it only occurs rarely at these settings). So under RISC OS 3.10 it is reccomended that you set your ADFSBuffers to 8+. There is a patch module available, called ADFSUtils, that does fix this problem - contact your local dealer for a copy of it. RISC OS 3.5 seems to have all of these problems cured and no new bugs introduced. Under 3.5 the number of ADFSBuffers can be left at the OS's discretion and generally the OS chooses a number based on the amount of memory present in your RiscPC. As for the optimum settings for ADFSBuffers, as far as I am aware no one has done any speed tests to see what is the best setting. Presumably though Acorn will have arranged for the system to start up (Well except for RO3.00...) in the optimum state for most uses. I would be interested in anyone who has done speed tests sending me the results of their investigations.... ---------------------------------------------------------------------------- 3.2) How do I enable solid drags in RISC OS 3? Solid drags are controlled by bit 1 in byte 28 of the CMOS RAM. Setting this bit enables solid drags on all solid drag 'aware' applications. However setting this bit using a *FX command from the command line is a foolish way to do it, as this will unset/set the other 7 bits in that byte which have meaning to FileSwitch and the Wimp. Accordingly the reccomended way to set this bit is using a program like this BASIC one enclosed below :- REM Toggle state of DragASprite bit in CMOS REM Read byte SYS "OS_Byte",161,&1C TO ,,byte% REM EOR byte with mask for bit 1 byte% = byte% EOR 1<<1 REM Write byte back again SYS "OS_Byte",162,&1C,byte% END Which safely sets bit 1 while preserving the settings of the other bits. ---------------------------------------------------------------------------- Section 4: Hardware problems. ---------------------------------------------------------------------------- 4.1) My hard drive gives me disc errors when I use, what do the error numbers mean? The error numbers returned indicate the type of error encountered. Exactly why slightly more meaningful messages are not returned I am unsure. The error codes meanings are as follows :- ST506 error codes &01 ABT Command abort has been accepted &02 IVC Invalid command &03 PER Command parameter error &04 NIN Head positioning, disc access, or drive check before SPC has been issued &05 RTS TST command invalid after SPC &06 NUS USELD for a selected drive has not been returned &07 WFL Write fault has been detected on the ST506 interface &08 NRY Ready signal has been negated &09 NSC Seek completed (SCP) wasn't returned before a timeout &0A ISE SEK, or disc access command issued during seek &0B INC Next cylinder address greater than number of cylinders &0C ISR Invalid step rate: highest-speed seek specified in normal seek mode &0D SKE SEK or disc access command issued to drive with seek error &0E OVR Data overrun (memory slower than drive) &0F IPH Head address greater then number of heads &10 DEE Error Correction Code (ECC) detected an error &11 DCE CRC error in data area &12 ECR ECC corrected an error &13 DFE Fatal ECC error in data area &14 NHT In CMPD command data mismatched from host and disc &15 ICE CRC error in ID field (not generated for ST506) &16 TOV ID not found within timeout &17 NIA ID area started with an improper address mask &18 NDA Missing address mark &19 NWR Drive write protected IDE errors - As ST506, except: &02 IVC Command aborted by controller &07 WFL Write fault &08 NRY Drive not ready &09 NSC Track 0 not found &13 DFE Uncorrected data error &16 TOV Sector ID field not found &17 NIA Bad block mark detected &18 NDA No data address mark &20 No DRQ when expected &21 Drive busy when commanded &22 Drive busy on command completion &23 Controller did not respond within timeout &24 Unknown code in error register ---------------------------------------------------------------------------- 4.2) My disc gives me a 'Broken Directory' or my Free Space Map is corrupt, what can I do? There are various programs out there now which fix this problem. The PD ones all are 'caveat emptor' programs but are worth trying if you vitally need to recover some files, or just don't have the floppy disc/streamer space to back your drive up. In the FAQ maintainer's experience the utility 'fsck' (a shareware utility available at good FTP sites near you) works reliably and well. Even so it is reccomended that if you have critical data on your drive you should use something like fsck to recover the data and then reformat the drive. ---------------------------------------------------------------------------- 4.3) What does the power on self-test check and how does it signal errors back to you? The purple screen at power on indicates that the self-test has begun. A brief ROM, RAM, VIDC and IOC test is performed and then the screen colour changes to blue and a full memory test is performed, along with a second test of the VIDC and IOC. When the screen returns to purple, the machine is testing for an ARM3. At the end of this sequence the screen colour is set to green (for pass) or red (for fail). If the tests have all passed then the machine starts to boot and the RISC OS 3 welcome screen is displayed. If any test fails, the screen will remain red and the disc drive light will blink a fault code. A short flash is used to indicate a binary '0' and a long flash indicates a binary '1'. The bits are grouped into eight nybbles (blocks of four bits) with the most significant bit first. The lowest seven bits are a status word. The meaning of each bit is given below in hex :- 00000001 Self-test due to power on 00000002 Self-test due to interface hardware 00000004 Self-test due to test link 00000008 Long memory test performed 00000010 ARM 3 fitted 00000020 Long memory test disabled 00000040 PC-style IO world detected Bits 8-31 indicate the fault code and are described below. Not all the bits are used. 00000200 ROM failed checksum test 00000400 MEMC CAM mapping failed 00000800 MEMC protection failed 00004000 VIDC Virq (video interrupt) timing failed 00008000 VIDC Sirq (sound interrupt) timing failed 00020000 RAM control line failure 00040000 Long RAM test failure Some third party VIDC enhancers on older hardware trigger the self test to fail. If you are getting a failed self test with a VIDC enhancer, yet the machine is working fine, enter and run this BASIC program and then save your CMOS settings :- REM Toggle state of power on self test bit in CMOS REM Read byte SYS "OS_Byte",161,&BC TO ,,byte% REM EOR byte with mask for bit 1 byte% = byte% EOR 1<<7 REM Write byte back again SYS "OS_Byte",162,&BC,byte% END This modifies the self test to cope with the VIDC enhancer. ---------------------------------------------------------------------------- 4.4) My Real Time Clock has paused, how do I restart it? This is a problem caused most often by 'rogue' software chatting to the IIC bus and incorrectly setting the pause bit on the RTC control register. Symptoms of this happening are that the time is always the same everytime you reboot and the software clock tends to run slightly slow (losing about a minute every hour or so.). If you are experiencing these symptoms this program should restart your RTC clock :- REM poke RTC control register REM Bit 0 1 REM 7 Count ResetDivider REM 6 Count HoldLastCount REM write 0 for normal operation, write &80 or &40 freezes RTC DIM cmosdata% 16 !cmosdata%=&00000000 REM write 0 twice to RTC, first 0 is address- control reg REM second is control reg value 0 is defualt i.e. clock on SYS &240, &A0, cmosdata%,2 END You will need to reset the time after running this program but hopefully your RTC will keep the correct time from here on in. If the same symptoms persist after trying this program contact your local Acorn dealer as something more serious has gone wrong. Note that to check that the symptoms are persisting you *must* reboot your machine after running this program and having set the time. This is due to the way RISC OS maintains a 'soft' copy of the real time clock and until you reboot it will not be obvious whether your RTC has indeed started working again. ---------------------------------------------------------------------------- Section 5: Software Issues. ---------------------------------------------------------------------------- 5.1) When using DOS discs I often find the last parts of files haven't been written correctly, what am I doing wrong? Under RISC OS 3 DOS, and indeed with any other ImageFS filing system, discs are treated as one large file and ADFS applies write-behind caching to nearly everything it does. (See the question on ADFSBuffers for more details about this.) This means while working on a DOS disc the entire disc is treated as one large open file. However as long as a file is held open the cache is not flushed out fully till the machine is explicitly told to do so. This means when working with non-ADFS format discs *always* dismount them before removing them from the drive. With ADFS format discs this is not so critical, as files aren't held open during most operations on them, but it is good to get into the habit of dismounting floppy discs. ---------------------------------------------------------------------------- 5.2) I have obtained [PD] program X but find it needs [version Y.YY of] module Z, which I don't have. Where can I get it? All patch modules, official Acorn OS extensions and the like can be sourced from the Acorn ftp site. Ideally your dealer will also have copies of them too and you should be able to obtain them from them. (If they don't you may like to pass on the ones from the ftp site, if you request them, so that they are up to-date.) ---------------------------------------------------------------------------- 5.3) What is the current File-type allocation ranges and why won't Acorn provide a full file-type list? Acorn have reallocated the File-type ranges for applications. The new ranges are :- Non-user area &E00-&FFF Acorn &B00-&DFF Commercial software &A00-&AFF Acornsoft, and other commercial software &400-&9FF Commercial Software User area &100-&3FF Non-commercial distributed software (ie PD) &000-&0FF User's personal usage (ie non-distributed) 75% of the user area is for PD/Shareware, with allocations co-ordinated by Acorn. If your software is going to be distributed, you should have an allocated filetype to avoid clashes. Acorn cannot publish it's master list of filetypes because, at any given time, it will contain allocations made for products which have not yet been announced. Therefore, Acorn would be in breach of confidence by doing so - and the editing overhead for producing a sanitised list is too great. ---------------------------------------------------------------------------- 5.4) Is there a Modula 2 compiler for the Arc? Currently, no. Acorn did have, in the early days of the experimental ARM work, an in house compiler. However this compiler was sufficiently unstable and buggy to be unreleasable as commercial product and was only used because in house support was available immediately to the users of the compiler. When Olivetti invested in Acorn this technology went to them so that Acorn no longer have even an in house Modula 2 compiler. However some companies have stated intentions to produce Modula 2 compilers for the Arc. Whether these intentions become reality has yet to be seen. ---------------------------------------------------------------------------- 5.5) What version of module X can I assume that all users have? Currently the version numbers are :- Clib v3.75 Colours v0.52 FPEmulator v2.80 IRQUtils v0.12 Hourglass v2.02 Sound v1.13 WimpUtils v0.04 All of these modules are only needed if you intend running your applications on RISC OS 2 machines. The functionality of all these module versions have been incorporated into ROM under RISC OS 3. ---------------------------------------------------------------------------- 5.6) What's the minimum version of module X that my program needs? What features were introduced/what bugs were fixed in which versions? These details will come with the release notes accompanying the module and the particular program, if properly done, will inform you of which versions of the module you need as required. ---------------------------------------------------------------------------- Section 6: Viruses. ---------------------------------------------------------------------------- 6.1) How can I protect against viruses? Pineapple Software have produced a program called !Killer, which is the definitive means of checking for or killing viruses. See the next question. There are also a few PD programs around, but these tend to detect only a small subset of the viruses in circulation. !VKiller used to be OK, but it is no longer maintained, is now seriously out of date and fails to work under RISC OS 3. Out of the PD virus utilities the current best is Tor Houghton's Scanner. This detects most known viruses and removes quite a few as well and serves as a good secondary defence if Killer is unavailable to you. Scanner should be available on various FTP/Email servers. ---------------------------------------------------------------------------- 6.2) Where can I obtain !Killer? It is now a commercial product and will be distributed by Pineapple Software. Who can be reached at:- 39 Brownlea Gardens, Seven Kings, Ilford, ESSEX IG3 9NL Tel. +44 (81) 599 1476 Fax +44 (81) 598 2343 via email :- sales@pinesoft.demon.co.uk support@pinesoft.demon.co.uk Early versions (up to 1.26) are PD, but should not be used now as they are ineffective against the new crop of viruses that have subsequently appeared since it's release. ---------------------------------------------------------------------------- Section 7: Net Resources. ---------------------------------------------------------------------------- 7.1) What archives/FTP sites are available? See the regular (fortnightly) posting by Gerben Vos. This posting is also available from an email server at MIT. To request it from this server send an email to mail-server@rtfm.mit.edu. No subject is needed and the body should contain :- send /pub/usenet/news.answers/acorn/archives ---------------------------------------------------------------------------- 7.2) What Acorn related companies are available on the net via email? There are quite a few companies now on the net and reachable via email with more joining as time passes. Here is the list of companies that have given permission to be entered here in the FAQ. If the email address is to a person rather than either an automated system or perhaps a group of people I have placed the name of the person in brackets after the email address description. Acorn Computers (Uk) :- customer.services@acorn.co.uk Enquiries and product information. RiscPC.techquery@acorn.co.uk RiscPC information. Aleph One :- Sales@aleph1.co.uk Information about products and prices. Support@aleph1.co.uk After-sales support. Armstrong Walker Ltd :- Andy@armswalk.demon.co.uk Enquiries etc... (Andy Armstrong) Nigel@armswalk.demon.co.uk Enquiries etc... (Nigel Walker) Atomwide :- Sales@atomwide.co.uk Information about products and prices. Support@atomwide.co.uk After-sales support. Clares Micro Supplies :- DClare@Clares.demon.co.uk General enquiries. (Dave Clare) GOwen@Clares.demon.co.uk General enquiries. (Gareth Owen) DJackson@Clares.demon.co.uk Technical enquiries. (David Jackson) Sales@Clares.demon.co.uk Ordering and sales information. Colton Software :- info@colton.co.uk Automated reply, listing services available. sales@colton.co.uk general sales etc. support@colton.co.uk technical support on existing products. Computer Concepts :- info@cconcepts.co.uk Automated reply, giving information. sales@cconcepts.co.uk For credit card orders of products. support@cconcepts.co.uk Technical support for products. Comspec :- acorn_info@comrad.comspec.com Canadian Acorn dealer. Enquiries about Acorn hardware and products welcome including USA enquiries. (Domenic DeFrancesco) David Pilling Software :- david@pilling.demon.co.uk All enquiries to this address. DoggySoft :- sales@doggysft.demon.co.uk Sales enquiries. support@doggysft.demon.co.uk Support for DoggySoft products. wxiibeta@doggysft.demo.co.uk Requests for WimpExt II beta testers. Iota Software :- support@iota.co.uk Enquires & support for Iota products. Learning Curve Software Systems :- banks_p@kosmos.wcc.govt.nz Enquiries & technical support. (Philip R. Banks) howard_s@kosmos.wcc.govt.nz Enquiries. (Steve Howard) wright_j@kosmos.wcc.govt.nz Enquiries & technical support. (Julian Wright) Machine Love :- csyss1@scs.leeds.ac.uk Enquries etc... (Shane Suebsahakarn) Oregan Software Developments :- sales@oregan.demon.co.uk General enquiries, product info and credit card orders support@oregan.demon.co.uk Technical queries PEP Associates :- info@pep-assoc.co.uk Product information. support@pep-assoc.co.uk Product support. SENLAC Computing :- sykesp@senlac.demon.co.uk Enquiries etc. (Peter R. Sykes) The Serial Port :- altman@cryton.demon.co.uk Software support. bob@cryton.demon.co.uk Retail enquiries. jim@cryton.demon.co.uk To reach Jim Nagel, author of the Acorn column in Computer Shopper magazine. pcats@cryton.demon.co.uk Hardware support Sherston Software :- sales@sherston.co.uk Sales and Product information. support@sherston.co.uk Technical support/queries etc. Spacetech Imaging Technology details@spacetec.demon.co.uk Automated product list server. (Send it a blank message to receive product details.) pdesk@spacetec.demon.co.uk Mailing list about Photodesk. (Send it a blank message to join the mailing list.) sales@spacetec.demon.co.uk Sales and Product information. support@spacetec.demon.co.uk Technical Support. Uniqueway :- info@uniqway.demon.co.uk General queries, product related or otherwise. support@uniqway.demon.co.uk Support for products. (Serial number should be quoted where relevant.) sales@uniqway.demon.co.uk For credit card orders. Warm Silence Software :- Robin.Watts@prg.ox.ac.uk Enquiries etc. (Robin Watts) Wyddfa Software gwilliams@cix.compulink.co.uk Enquiries etc. (Gwyn Williams) If you are a company and you would like to included in this list please send me an email, to the address specified at the bottom of the FAQ, detailing the email addresses and their general function. I will then include them into the FAQ. ---------------------------------------------------------------------------- 7.3) Why have there been no postings to comp.{binaries,sources}.acorn recently? The moderator runs c.b.a and c.s.a in their spare time. They may not have any at the moment - they're studying hard at University. Please be aware the submissions address for the binaries and sources groups is cba@acorn.co.nz and *not* the moderator's 'home' addresses - the distinction is important as they have to pay for incoming email at these addresses. ---------------------------------------------------------------------------- 7.4) How to retreive the FAQ from the source... { Or how to use my email server. } As I frequently update the FAQ between postings you may wish to get the latest and most up-todate copy of the FAQ before it next gets posted. To allow you to do this, and to reduce the size of the FAQ itself, I maintain an email server on my personal machine for people to use. Due to the various complications at my end, and a distincct desire to minimise email charges incurred to myself, the email server shares my email address with me. To use the server send an email message looking something like this :- To: banks_p@kosmos.wcc.govt.nz Subject: ServerMail ---message text begins--- Help: In this case it will send a help file to you detailing how to use the server. Be aware that the spelling and case of the subject line is *very* important. My software searches for email with exactly this subject line automatically once a day and it is case & spelling sensitive. Failure to type this correctly will result in your message appearing in my normal email list and depending on my mood may, or may not, be adjusted to reach the email server. The server understands and uses Reply-To: headers but has distinct problems sending material to bang path addressed sites. (Well to be more accurate it has problems sending to any site that has an ! in the email address.) If you are using a site with such addressing then I am afraid the email server will be unable to help you. Also please ensure that your From: header, or your Reply-To: header if you using that, is valid. Email file requests that bounce due to this tend to annoy me and repeat offenders will be placed on the server's 'to be ignored' list. As well as the FAQ and it's related files I store a small collection of technical documents, 'special' data files and other generally useful data on the server. To obtain a listing of all the sections available to you, and the contents of those sections, send a message as detailed above but instead of help put :- Send: index in the body of the message. Please be aware that this server is at the tail end of a 2400 baud link so while you are most welcome to use it I must ask that you try to source any files from other sites before using this server and to strictly follow the guidelines outlined above. ---------------------------------------------------------------------------- 7.5) What WWW pages are out there for Acorn topics? Web pages are popping up all over the place these days, especially now that Web client software exists for Acorn machines. This list of Web pages is checked periodicly by myself for validity but I make no claims that URL's present here are currently valid. <http://www.geko.com.au/users/riscman/index/html> Australian Acorn Web site. Still growing [read: under development] ---------------------------------------------------------------------------- Thanks go to all the people who have contributed corrections and additions to the list. Without this help this list would be a hell of alot buggier (spot the programmer... :-) ) than it is... ---------------------------------------------------------------------------- All additions, corrections & suggestions for the FAQ List should be sent to -=> banks_p@kosmos.wcc.govt.nz <=- Being the maintainer of this FAQ I reserve the right to be wrong, incorrect, slow, out of date and generally how I please with the FAQ List.