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Xref: bloom-picayune.mit.edu comp.sys.acorn.announce:74 comp.sys.acorn:12758 news.answers:4638 Newsgroups: comp.sys.acorn.announce,comp.sys.acorn,news.answers Path: bloom-picayune.mit.edu!khantazi.welly.gen.nz!banksie From: banksie@khantazi.welly.gen.nz (Philip R. Banks) Subject: Comp.Sys.Acorn FAQ List Posting (Automatic) Message-ID: <1992Dec17.144917.7204@athena.mit.edu> Followup-To: comp.sys.acorn Keywords: Frequent Questions Answers Sender: news@athena.mit.edu (News system) Nntp-Posting-Host: pit-manager.mit.edu Reply-To: banks_p@kosmos.wcc.govt.nz Organization: My Arc. Date: Thu, 17 Dec 1992 14:49:17 GMT Approved: announce@acorn.co.uk Lines: 917 Archive-name: acorn/faq Comp.Sys.Acorn FAQ List. Last alterations 10/Dec/1992 ----------------------------------------------------- ------------------------------------------------------------------------------- Recent alterations :- -Minor fix to the Master 512 co-processor entry. -Question 20 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.... When reading this FAQ List it is reccomended that you use a text editor if you are not interested in reading every question's answer. Each answer is seperated by a line of '-' characters. To find the answer you are interested in try searching for (in !Edit) "--\x0AQ##)" using Magic characters where ## is the question number you are interested in the answer to. This will leap directly to the answer. 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 stored there is Gerben Vos's Acorn Archive list. This can be obtained in a similar manner to the faq with the email body being :- send /pub/usenet/news.answers/acorn/archives Finally sections of this FAQ are stored in another email server to reduce bandwidth when posting it due to these sections being commonly asked but not quite often enough to warrant the continual posting. To obtain these sections from the email server send mail to the address 'banks_p@kosmos.wcc.govt.nz' with the subject (case and spelling important ignore the quotes.) "ServerMail". The body of the message should be of the form :- Start: [line-limit: <x lines per message>] Section: FAQData Send: <filename> End: All commands in the body of the message are case insensitive. The line-limit command is completely optional and multiple send commands are possible if you to request more than one file at a time. Please remember that this server is a) in Beta test. I only coded it recently and there may be some lurking bugs in it yet. & b) at the other end of a 2400 baud modem. Thus frivoulous requests for large files will not be appreciated. Also if you get the Subject lines case or spelling wrong that email will be sent to me instead of the server. Not unsurprisingly I probably won't be terribly appreciative to receive email server requests in my personal email section... Index of Questions ------------------ Q1) 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? Q2) What version of module X can I assume that all users have? Q3) What's the minimum version of module X that my program needs? What features were introduced/what bugs were fixed in which versions? Q4) I have had problems with my printer. It's a dot matrix printer, when printing graphics or a document, it sometimes mangles a line of output, usually printing a $ sign, too. Q5) Why have there been no postings to comp.{binaries,sources}.acorn recently? Q6) What archives/FTP sites are available? Q7) How can I protect against viruses? Q8) Where can I obtain !Killer? Q9) What is a VIDC enhancer? Will I need one for my new multisync monitor? Q10) What are the main new features of RISC OS 3? Q11) How do I enable solid drags in Risc OS 3? Q12) What kind of Acorn machines are there? Q13) What are the memory limits of the Acorn machines? Q14) What is a second processor and what second processors are there? Q15) Are there any cards for IBM PC or compatable machines that Acorn have produced? Q16) What configuration of cable should I use on my Arc for modem work? Q17) Can PC VGA Monitors be added to an Archimedes? Q18) What is ADFSBuffers and what is the best setting for it? Q19) What is the current File-type allocation ranges and why won't Acorn provide a full file-type list? Q20) My disc gives me a 'Broken Directory' or my Free Space Map is corrupt, what can I do? ---------------------------------------------------------------------------- Q1) 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 and current versions of Clib and its ilk are sited on the NZ info-server and can be obtained from there. Ideally your local 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 info-server if you request them, so that they are up to-date.) ---------------------------------------------------------------------------- Q2) 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 ---------------------------------------------------------------------------- Q3) 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. ---------------------------------------------------------------------------- Q4) I have had problems with my printer. It's a dot matrix printer, when printing graphics or a document, it sometimes mangles a line of output, usually printing a $ sign, too. Get your dealer to carry out Field Change Order XXX (which corrects the problem). Or if you are competant enough do it yourself like this :- 1) Remove the circuit board from the computer. 2) Locate and identify resistor R24. Cut the leg of R24 closest to IC9, and carefully move the free end of R24 away from the adjacent resistor. Secure R24 to the PCB with adhesive (for example Loctite TAC PAC), leaving the free end of R24 available for soldering. 3) Prepare new IC (74HC14) by: Removing pins 5,6,8,9,10,11,12 and 13 Lift pins 1 and 4 ready to solder leads Lift pins 2 and 3, and solder them together 4) Position new IC onto IC15 piggyback fashion so that pin 1 of the new IC is directly above pin 1 of IC15. Solder pins 7 and 14 of the new IC to pins 7 and 14 of IC15. 5) Solder thin insulated lead from pin 1 of the new IC to the free end of R24. Solder a second insulated lead from pin 4 of the new IC to the vacated pad of R24. Keep these leads as short as possible, and secure them to the PCB with adhesive. 6) Reassemble the computer and check operation of the printer port. The 74HC14 IC is widely available.........(Acorns part No).... Please note that it is particularly important that a profile of this modification is kept as low as possible, to ensure that there is no fouling of the modification on any podules that may be fitted to the computer. Be warned that modifying your Archimedes invalidates the warranty on it and should preferrably be carried out by an Acorn sanctioned technician. ---------------------------------------------------------------------------- Q5) Why have there been no postings to comp.{binaries,sources}.acorn recently? The moderators run 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. ---------------------------------------------------------------------------- Q6) What archives/FTP sites are available? See the regular (fortnightly) posting by Gerben Vos. ---------------------------------------------------------------------------- Q7) How can I protect against viruses? Acorn 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 virues and removes quite a few as well and serves as a good secondary defense if Killer is unavailable to you. Scanner should be available on various FTP/Email servers. ---------------------------------------------------------------------------- Q8) 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 Early versions (up to 1.26) are PD, but should not be used now as they are ineffective against the new crop of virus that have subsequently appeared since it's release. ---------------------------------------------------------------------------- Q9) 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 A5000 and the A540) 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. ---------------------------------------------------------------------------- Q10) What are the main new features of RISC OS 3? Most of the features of Risc OS 3 are behind the scenes stuff for programmers, improving the program to OS interfaces. However there are quite a few improvements to the user interface :- * Multitasking Filer operations. Copying, moving, and deleting files no longer takes control away from the user. The user can now go on using the computer while the filing operations are taking place. * Multitasking Format/Verify/Backup These operations, which used to take a long time on RISC OS 2.00 are now performed in the background, enabling the user to continue and make other use of the computer while they are taking place. * Multitasking Free space display. The free space display for floppy and hard discs now gives a continuous view of the free space on the disc while the computer is being used. * Additional Filer operations. It is now possible to search for a file, set a file's type, and date stamp a file from the Filer menu. * Applications in ROM. Improved versions of many of the main applications that were provided on disc with RISC OS 2.00 are now resident in ROM. These applications can be accessed using the Apps icon on the left hand side of the icon bar. * Automatic starting of applications Any of the ROM applications can be set to start automatically when the computer is powered on. * Fonts in ROM Many of the fonts that were provided on disc with RISC OS 2.00 are now resident in the RISC OS 3 ROM. * No limit on number of open windows. There is no longer a limit on the number of windows that can be opened at once. * Ability to move windows off screen. Windows can now be moved partly off screen, to increase the usable screen space. * Desktop saving Ability to save the computer's state and restore it when the user next uses the machine. * Computer shutdown. An option is provided to safely close the computer down, ready for turning it off. * Pinboard. Frequently used files can now be held on the desktop background for easy access. A background picture can also be displayed on the desktop. * Iconized windows. An open window can be shrunk to an icon, and stored on the desktop background. It can later be restored to its previous size be clicking on the icon. This helps reduce the space used by windows when they are not being actively used. * Improved printer support. A new printer driver manager !Printers is provided with RISC OS 3 which makes printing easier. RISC OS 3 makes it possible to have more than one printer connected to your computer at the same time, with all connected printers accessible from the desktop. * Ability to read MS DOS(tm) format discs. It is now possible to use discs that were created on a computer running MS DOS(tm) from RISC OS 3 to move data between the Acorn range of computers and any computer running MS DOS(tm). * Support for new A5000 high density floppy formats. It is now possible to use 1.6MB floppy discs on computers which support it such as the A5000. * Broadcast Loader. RISC OS 3 includes support for broadcast loading on Econet networks. This greatly improves the speed at which applications and data are loaded on multiple computers on the network. * ARM3 support. RISC OS 3 includes built in support for the ARM3 processor that is used on the A540,R260 and A5000 computers. * Ability to use named hard discs. Hard discs which are given a name now have their name displayed under their icon on the icon bar, eliminating the need to refer to the same disc by both its name and number. * Grouping of icon bar icons. On RISC OS 3 icons of the same type will appear on the icon bar in a group, regardless of the order they were added to the icon bar. For instance all hard disc icons will appear in a group, and so will all the fileserver icons. This makes finding the icon you want easier. * Enhanced interactive help. When running !Help, help can now be provided on menu items as well as on icons and windows, making it easier to learn how to use new application software. * Extension modules in ROM. All of the standard extension modules for RISC OS 2.00 such as ColourTrans, the floating point emulator, the outline font manager and the shared C library are now in the RISC OS 3 ROM leaving more memory for application software. * Up to 128 tasks. RISC OS 3 can support up to 128 tasks running together in the computer as opposed to the 32 allowed by RISC OS 2.00. * New hot keys. New hot keys are provided to open a task window, move the icon bar to the front, and start a shutdown. * Screen blanker. A screen blanker is included in the RISC OS 3 ROM to help preserve the monitor screen. (lifted from Ran Mokady's RO3 Q&A posting. Thanks Ran....) ---------------------------------------------------------------------------- Q11) 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. (thanks go to Micheal J Hardy for this one.) ---------------------------------------------------------------------------- Q12) What kind of Acorn machines are there, and what are their specifications? 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 current commonly ecountered Acorn machines. 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. A500 - never sold commercially this machine will be a little hard to find. It was the development machine for the A300/A400 series of machines. One of its major `idiosyncracies` is that it uses the older VIDC1 chip which used different logic for sound output than all commercialy released Arcs and thus most sound modules sound very odd on it... 4096k Memory. Advanced Disc Filing System by default. ARM 2 processor. 8 MHz RAM. (Ocassional unit with 12MHz RAM.) 512k OS in ROM. ~4 MIPS A3xx - the first of the Archimedes range of computers it was powered by a custom designed chip set based around the ARM a 32 bit RISC chip. The range started with half a Meg of memory up ran up to 1 Meg of memory. They came out with the Arthur Operating system that while it was more advanced than the 8 bit machines OS's it was not an OS doing justice to the hardware it was running on. Released around late 1987 they heralded the start of new shift in Acorn machines away from their previous 6502 only base. A305 512k Memory. Advanced Disc Filing System by default. ARM 2 processor. 8 MHz RAM. 512k OS in ROM. ~4 MIPS A310 1024k Memory Advanced Disc Filing System by default. ARM 2 processor. 8 MHz RAM. 512k OS in ROM. ~4 MIPS A4xx - released at the same time as the 300 series of machines the 400 series features an in built st506 hard drive controller and some models came equiped with hard drives built in as standard and the series also , by default, was capable of handling 4 expansion cards including a co-processor card unlike the 300 series. A410 1024k Memory Advanced Disc Filing System by default. St506 Hard Drive interface by default. ARM 2 processor. 8 MHz RAM. 512k OS in ROM. ~4 MIPS A420 2048k Memory Advanced Disc Filing System by default. St506 Hard Drive interface by default. ARM 2 processor. 8 MHz RAM. 512k OS in ROM. ~4 MIPS A440 4096k Memory Advanced Disc Filing System by default. St506 Hard Drive interface by default with Hard Drive. (43 Meg) ARM 2 processor. 8 MHz RAM. 512k OS in ROM. ~4 MIPS A680 - development machine for RISCiX. This is another development machine and again was never sold commercialy. Thus it is somewhat rare. It was different from most Arcs in the respect that it does not have RiscOS in ROM at all and can only use high resolution monochrome monitor for display. It came with a 67 Meg SCSI drive by default. 8192k Memory. SCSI by default. (67 Meg drive) ARM 2 processor. 8 MHz RAM. Unknown. (Runs RISCiX...) ~4 MIPS R140 - Acorn's entry machine into the Unix market, it suffered problems due to the Archimedes chip set not being optimal for running Unix on. Functionally identical to an A440 machine it had 4 Meg of memory and was provided with an 52 Meg st506 drive with RISCiX (Acorns brand of Unix) on it. 4096k Memory Advanced Disc Filing System by default. St506 Hard Drive interface by default with Hard Drive. (53 Meg) ARM 2 processor. 8 MHz RAM. 512k OS in ROM. RISCiX OS supplied on Hard Drive. ~4 MIPS A3000 - this is the low end Arc. It was the first machine to be released with the newer and faster MEMC1a built in as standard as well as the newer Risc OS by default. Designed to be a cost effective cheap Arc it features only one full expansion port with a single internal `mini` expansion card slot limiting expansion somewhat. It also came by default without a serial port. This machine has proved very popular with schools as a cheap entry into the new Archimedes machines. 1024k Memory Advanced Disc Filing System by default. ARM 2 processor. 8 MHz RAM. 512k OS in ROM. ~4.7 MIPS A4xx/I - this series was functionally identical to the 400 series but featured a newer memory controller the MEMC1a that gave it a slightly faster speed. It also came with a 53 Megabyte hard drive in the higher end models that came with HD's rather than the 400 series's 20 Meg one. A420/I 2048k Memory Advanced Disc Filing System by default. St506 Hard Drive interface by default. ARM 2 processor. 8 MHz RAM. 512k OS in ROM. ~4.7 MIPS A440/I 4096k Memory Advanced Disc Filing System by default. St506 Hard Drive interface by default with Hard Drive. (53 Meg) ARM 2 processor. 8 MHz RAM. 512k OS in ROM. ~4.7 MIPS A540 - the current high end Archimedes machine this machine comes with 4 Meg of memory by default and an ARM 3 processor running at 26 MHz. It comes with a 100 Meg SCSI drive by default and a slightly newer version of Risc OS updated to cope with up to 16 Meg of memory and features for handling the ARM 3 processor. 4096k Memory Advanced Disc Filing System by default. SCSI Hard Drive interface by default with Hard Drive. (100 Meg) ARM 3 processor. 12 MHz RAM. 512k OS in ROM. ~13.5 MIPS (I am guessing here...) R260 - functionally identical to the A540 the R260 comes with Unix (well RISCiX ) by default and due to the increased power of the hardware runs it much better. 8192k Memory Advanced Disc Filing System by default. SCSI Hard Drive interface by default with Hard Drive. (100 Meg) ARM 3 processor. 12 MHz RAM. 512k OS in ROM. RISCiX OS supplied on Hard Drive. ~13.5 MIPS R225 - A diskless version of the R260 it was designed to be a cheap networked Unix station. Released at the same time as the R260. 4096k Memory Advanced Disc Filing System by default. ARM 3 processor. 12 MHz RAM. 512k OS in ROM. RISCiX OS booted off from Network connections. ~13.5 MIPS A5000 - the A5000 is the first machine to feature high density (quad - 1.6 Meg formated) drives by default as well as the latest version of Risc OS - version 3. It also features an inbuilt IDE drive on it's higher end model. Released late 1991. 1024k Memory Advanced Disc Filing System by default with High Density drives. IDE interface by default. ARM 3 processor 12 MHz RAM. 2048k OS in ROM. ~13.5 MIPS. 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 (6 MHz in power save mode.) 12 MHz RAM. (3 MHz in power save mode.) 2048k OS in ROM. ~13.5 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 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. Launched August 27th 1992. 1024k Memory Advanced Disc Filing System by default with High Density drives. IDE 60 Mb Hard Drive (only in A3020). 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 that the A300x0 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 ---------------------------------------------------------------------------- Q13) What are the memory limits of the 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. For the 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 Megs maximum through third party, 1 Meg official limit. A4xx & A4xx/I - 8 Megs maximum through third party, 4 Megs official limit. A3000 - 4 Megs maximum through third party, 2 Megs official limit. A540 - 16 Megs maximum. A5000 - 8 Megs maximum through third party, 4 Megs official limit. A4 - 4 Megs official limit. A30x0 - 2 Megs official limit. A4000 - 4 Megs official limit. ---------------------------------------------------------------------------- Q14) 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. 16032 second processor. Unknown. 256k-4096k Memory. Unknown. (Panos at a guess) External processor for all eight bit machines. ARM 2 second processor. 8 MHz RAM. (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. ---------------------------------------------------------------------------- Q15) 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. ---------------------------------------------------------------------------- Q16) What configuration of cable should I use on my Arc 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, an 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. ---------------------------------------------------------------------------- Q17) Can PC VGA Monitors be added to an Archimedes? It depends on what monitor you have, and what Archimedes 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) Mutil 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 seperate 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 negligable. Now, depending on what type of Archimedes you have depends on what type of monitor you can use. A540 / A5000 Has software control over the polarity of the syncs and what frequency VIDC is clocked at. The A540 with RiscOS 2 can only use modes 26-28 (640x480) [I can't rember if an A540 has a mode 31, help?]. However, by changing links and a *configure option, you can get the computer to generate seperate syncs with no problem. The A5000 with RiscOS 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. Both the A540 / A5000 have a 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 incorect. 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 satisfactorly. 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 continously. There is only a 24Mhz crystal, and only composite PC VGA monitors can be used. Conclusion: Apart from the A5000, 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 to handle the needed timing and signals. ---------------------------------------------------------------------------- Q19) 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 improvment 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 A5000 machine, 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 A5000. Symptoms include reformating of crucial sectors of the disc, disc address errors and general failure to save files to the drive. So when using an A5000 remember to configure them to off! 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 the A5000...) 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.... ---------------------------------------------------------------------------- Q19) 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. ---------------------------------------------------------------------------- Q20) My disc gives me a 'Broken Directory' or my Free Space Map is corrupt, what can I do? Unfortunately due to the highly complicated nature of the filing system data there is little that can be done easily. Your simplest and best way of correcting the problem is to backup as much software as you can and reformat your drive, restoring everything from those backups you make regularly... (What you don't back up your discs? :-) ) To do anything else requires a good knowledge of how the underlying structures work and is beyond the scope of this FAQ, although this detail is covered in the Risc OS 3 PRMs. ---------------------------------------------------------------------------- Thanks go to Julian Wright for his diagrams and comments on the serial port. Also 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 a student I reserve the right to be wrong, incorrect, slow, out of date and generally how I please with the FAQList.