Thread View: comp.sys.acorn.announce
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Started by Philip R. Banks
Wed, 05 Oct 1994 19:14
Comp.Sys.Acorn FAQ List Posting (Automatic)
Author: Philip R. Banks
Date: Wed, 05 Oct 1994 19:14
Date: Wed, 05 Oct 1994 19:14
1340 lines
59668 bytes
59668 bytes
Archive-name: acorn/faq
Comp.Sys.Acorn FAQ List. Last alterations 16/Sep/1994
-----------------------------------------------------
----------------------------------------------------------------------------
Recent alterations :-
Q25 updated slightly.
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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 recommended that you use a text editor
if you are not interested in reading every question's answer. Each answer is
separated 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 frivolous 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) When using DOS discs I often find the last parts of files haven't been
written correctly, what am I doing wrong?
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 compatible machines that Acorn have
produced?
Q16) What configuration of serial 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?
Q21) My hard drive gives me disc errors when I use, what do the error
numbers mean?
Q22) What does the power on self-test check and how does it signal errors
back to you?
Q23) Is there a Modula 2 compiler for the Arc?
Q24) Is Virtual Memory possible under RISC OS?
Q25) How compatible with other systems is an Archimedes?
Q26) What Acorn related companies are available on the net via email?
Q27) What versions of the processor are there and what are their
capabilities?
Q28) What are the graphics capabilities of the Acorn machines?
Q29) What are the differences between RISC OS 3.5 and RISC OS 3.11 & 3.10?
Q30) My Real Time Clock has paused, how do I restart it?
----------------------------------------------------------------------------
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 if you are sited in NZ.
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 info-server if you request them, so that they are up to-date.)
Finally some versions of the patch modules (mostly the newer ones for RISC OS
3) are sited at the Acorn ftp site. In the future it is expected that the
Acorn ftp site will become the primary place for sourcing the current module
version on the internet.
----------------------------------------------------------------------------
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
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.
----------------------------------------------------------------------------
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
and the particular program, if properly done, will inform you of which
versions of the module you need as required.
----------------------------------------------------------------------------
Q4) 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.
----------------------------------------------------------------------------
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. Please be
aware the submissions address for the binaries and sources groups is
cba@acorn.co.nz and *not* the moderators 'home' addresses - the distinction
is important as they have to pay for incoming email at these addresses.
----------------------------------------------------------------------------
Q6) What archives/FTP sites are available?
See the regular (fortnightly) posting by Gerben Vos.
----------------------------------------------------------------------------
Q7) 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.
----------------------------------------------------------------------------
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
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 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 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.
----------------------------------------------------------------------------
Q10) 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'.
----------------------------------------------------------------------------
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 Michael 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 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. It is interesting to note that the A4 is *not* an
A5000 squeezed into portable form but rather the A5000 is the A4 in
desktop form, whereby the A5000 design was largely a spin off from the
design of the A4.
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.)
----------------------------------------------------------------------------
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. (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 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 - 4 Megs official limit.
A4000 - 4 Megs official limit.
A5000 (alpha variant) - 8 Megs official limit.
Newer RiscPC machines have an official upper limit of 256 Megs, plus 2
Megs of VRAM, on all models. However this does require you using 128 Mbyte
SIMMS which are currently not very common...
----------------------------------------------------------------------------
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.
32016 second processor.
6 MHz RAM.
256k-4096k Memory.
Panos.
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 serial 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, 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.
----------------------------------------------------------------------------
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) 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 to handle the needed timing and signals.
----------------------------------------------------------------------------
Q18) 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 to 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.
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....
----------------------------------------------------------------------------
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?
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.
----------------------------------------------------------------------------
Q21) 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
----------------------------------------------------------------------------
Q22) 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.
----------------------------------------------------------------------------
Q23) 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.
----------------------------------------------------------------------------
Q24) 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.
----------------------------------------------------------------------------
Q25) How compatible with other systems is an Archimedes?
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.
----------------------------------------------------------------------------
Q26) 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.
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)
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
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.
----------------------------------------------------------------------------
Q27) 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 start of the FAQ for requesting this file.
----------------------------------------------------------------------------
Q28) 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
320 256 4
160 256 4
160 256 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
320 256 2
640 256 2
640 480 2
640 512 2
1152 896 2
160 256 4
320 256 4
640 250 4
640 256 4
640 480 4
640 512 4
160 256 16
320 256 16
640 250 16
640 256 16
640 480 16
640 512 16
1056 250 16
1056 256 16
160 256 256
320 256 256
640 256 256
640 480 256
640 512 256
1056 256 256
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
320 256 2
640 200 2
640 256 2
640 480 2
640 352 2
640 512 2
768 288 2
800 600 2
896 352 2
1152 896 2
160 256 4
320 256 4
640 200 4
640 250 4
640 256 4
640 352 4
640 480 4
640 512 4
768 288 4
800 600 4
896 352 4
160 256 16
320 256 16
640 200 16
640 250 16
640 256 16
640 352 16
640 480 16
640 512 16
768 288 16
800 600 16
896 352 16
1056 250 16
1056 256 16
160 256 256
320 256 256
640 200 256
640 256 256
640 352 256
640 480 256
640 512 256
768 288 256
896 352 256
1056 256 256
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
320 256 2
640 200 2
640 256 2
640 480 2
640 352 2
640 512 2
768 288 2
800 600 2
896 352 2
1152 896 2
160 256 4
320 256 4
640 200 4
640 250 4
640 256 4
640 352 4
640 480 4
640 512 4
768 288 4
800 600 4
896 352 4
1280 1024 4
160 256 16
320 256 16
640 200 16
640 250 16
640 256 16
640 352 16
640 480 16
640 512 16
768 288 16
800 600 16
896 352 16
1024 768 16
1056 250 16
1056 256 16
1280 1024 16 1 MB of VRAM
160 256 256
320 256 256
640 200 256
640 256 256
640 352 256
640 480 256
640 512 256
768 288 256
800 600 256
896 352 256
1024 768 256 1 Mb of VRAM
1056 256 256
1280 1024 256 2 Mb of VRAM
1600 1200 256 2 Mb of VRAM
800 600 32,000 1 Mb of VRAM
1024 768 32,000 2 Mb of VRAM
800 600 16,000,000 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.
----------------------------------------------------------------------------
Q29) 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.
----------------------------------------------------------------------------
Q30) 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 puase 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.
----------------------------------------------------------------------------
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.
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