RISC OS harddisc sizes

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Ian K (N)

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Aug 17, 2007, 3:40:37 PM8/17/07
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Hello All

Can someone tell me the maximum harddisc size supported by ADFS on RISC OS
3.5, 3.6 and 3.7. Their seems to be some confusion round and about the
internet as to what the official limits are.

Regards
Ian K

Jess

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Aug 17, 2007, 4:06:44 PM8/17/07
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In message <4f13eef...@iank.org.uk>

"Ian K (N)" <ne...@iank.org.uk> wrote:

> Hello All
>
> Can someone tell me the maximum harddisc size supported by ADFS on RISC OS
> 3.5,

This is the same as 3.1, 512MB (but as I understand it is far better
to go for 499MB for cluster size.)

> 3.6 and 3.7. Their seems to be some confusion round and about the
> internet as to what the official limits are.

3.6 and 3.7 are the same. Apparently they can go quite large (128GB?)
but become incredibly inefficient above a few GB (so perhaps using
archives is advisable for small files.) Also ADFS buffers has to be
set to zero to avoid disc corruption with large drives (above 2GB?).

Hopefully someone will confirm or correct these figures.
--
Jess Iyonix
Hotmail is my spam trap use this for reply:
mailto:nos...@jess.itworkshop-nexus.net or
http://jess.itworkshop-nexus.net

P M Noble

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Aug 17, 2007, 4:22:22 PM8/17/07
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In article <4f13eef...@iank.org.uk>,

Ian K (N) <ne...@iank.org.uk> wrote:
> Hello All

On the same line, what are the sizes for RO 5. I understand that it is
128GB, but can I get a 250GB drive and create 2 partitions on it, or is it
that each drive can only be useful upto 128GB.

Peter

--
Peter Noble

Goto www.ishanipeter.com - for our website

druck

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Aug 17, 2007, 4:32:50 PM8/17/07
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> Hello All

On Risc PC / A7000(+) hardware:-

3.5 or earlier : 512MB
3.6 and later : 128GB

---druck

--
The ARM Club Free Software - http://www.armclub.org.uk/free/
The 32bit Conversions Page - http://www.quantumsoft.co.uk/druck/

Jess

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Aug 17, 2007, 4:38:47 PM8/17/07
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In message <4f13f2c77...@yahoo.co.nz>

P M Noble <pm_n...@yahoo.co.nz> wrote:

> In article <4f13eef...@iank.org.uk>,
> Ian K (N) <ne...@iank.org.uk> wrote:
>> Hello All
>
>> Can someone tell me the maximum harddisc size supported by ADFS on RISC
>> OS 3.5, 3.6 and 3.7. Their seems to be some confusion round and about
>> the internet as to what the official limits are.
>
> On the same line, what are the sizes for RO 5. I understand that it is
> 128GB, but can I get a 250GB drive and create 2 partitions on it, or is it
> that each drive can only be useful upto 128GB.

No. I have a 160GB drive on mine. I think it is that DMA only works in
the first 128GB after that it slows down.

Message has been deleted

Alan Adams

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Aug 18, 2007, 6:26:34 AM8/18/07
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In message <4f1405ee74inval...@invalid-domain.co.uk>
Paul Vigay <invalid-em...@invalid-domain.co.uk>
wrote:

> In article <3448f41...@itworkshop.invalid>,
> Jess <phant...@hotmail.com> wrote:

>> No. I have a 160GB drive on mine. I think it is that DMA only works in
>> the first 128GB after that it slows down.

> I've got a 160GB external USB2 drive which works fine on the Iyonix.

What's the performance like? I'm thinking about my Panther, which has
space for 6 drives, but no available IDE connections. I was thinking
about mounting USB drives inside the case...


--
Alan Adams, from Northamptonshire
alan....@orchard-way.freeserve.co.uk
http://www.nckc.org.uk/

Message has been deleted

Francis Devereux

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Aug 21, 2007, 4:40:59 AM8/21/07
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On Aug 17, 9:06 pm, Jess <phantasm...@hotmail.com> wrote:
> In message <4f13eef506n...@iank.org.uk>

> "Ian K (N)" <n...@iank.org.uk> wrote:
>
> > Hello All
>
> > Can someone tell me the maximum harddisc size supported by ADFS on RISC OS
> > 3.5,
>
> This is the same as 3.1, 512MB (but as I understand it is far better
> to go for 499MB for cluster size.)
>
> > 3.6 and 3.7. Their seems to be some confusion round and about the
> > internet as to what the official limits are.
>
> 3.6 and 3.7 are the same. Apparently they can go quite large (128GB?)
> but become incredibly inefficient above a few GB (so perhaps using
> archives is advisable for small files.) Also ADFS buffers has to be
> set to zero to avoid disc corruption with large drives (above 2GB?).

ROMPatch version 2.04 (beta) has a fix for an ADFSBuffers problem,
although the fix is "not yet audited" according to the !ReadMe:

-----------------------------------------------------------------------------
8) 3.60,3.70: With ADFSBuffers non-zero and a disc of more than 2Gb,
machine
may hang.

9) 3.70,3.71: C runtime sees uncaught trap if a SWI, called through
_swi
or _swix, aborts.

Problems 1 to 7 inclusive are fixed as for ROMPatch 2.02, problems 8
and 9
are new fixes, NOT YET AUDITED - see above warning.
-----------------------------------------------------------------------------

I have ROMPatch 2.04 installed on my RISC OS 3.70 Risc PC with 6GB
hard disc and am have ADFSBuffers set to 255. I have not had any
problems with this so far but I might be living dangerously... has
anyone else tried a similar setup and if so did it work?

Francis

Jess

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Aug 21, 2007, 5:06:53 AM8/21/07
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In message <1187685659.5...@o80g2000hse.googlegroups.com>


RISC OS 4 has fixed code, (presumably 3.8 too). If there's any way of
checking if the code needed to be further revised (unless it needed to
be for the new format) that might give a clue.

Alan P Dawes

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Aug 21, 2007, 6:17:54 AM8/21/07
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In article <1187685659.5...@o80g2000hse.googlegroups.com>,

Francis Devereux <fran...@gmail.com> wrote:
> > 3.6 and 3.7 are the same. Apparently they can go quite large (128GB?)
> > but become incredibly inefficient above a few GB (so perhaps using
> > archives is advisable for small files.) Also ADFS buffers has to be
> > set to zero to avoid disc corruption with large drives (above 2GB?).

> ROMPatch version 2.04 (beta) has a fix for an ADFSBuffers problem,
> although the fix is "not yet audited" according to the !ReadMe:

> -----------------------------------------------------------------------------
> 8) 3.60,3.70: With ADFSBuffers non-zero and a disc of more than 2Gb,
> machine
> may hang.

> 9) 3.70,3.71: C runtime sees uncaught trap if a SWI, called through
> _swi
> or _swix, aborts.

> Problems 1 to 7 inclusive are fixed as for ROMPatch 2.02, problems 8
> and 9
> are new fixes, NOT YET AUDITED - see above warning.
> -----------------------------------------------------------------------------

> I have ROMPatch 2.04 installed on my RISC OS 3.70 Risc PC with 6GB
> hard disc and am have ADFSBuffers set to 255. I have not had any
> problems with this so far but I might be living dangerously... has
> anyone else tried a similar setup and if so did it work?

You may juat be lucky. Here is a posting from csa.hardware 22Nov 1998 just
after RomPatch 2.04 (which confusingly sometimes is known as 3.70/3 or
3.71/3 as this is how it shows up in tasks with OS 3.07 and 3.71) which
suggests that all may not be well:

************************
"From: Ray Briddock <R...@alphabeta.demon.co.uk>
Subject: Re: More RPC problems
Date: Sun, 22 Nov 1998 02:55:00
Newsgroups: comp.sys.acorn.hardware

In message <MPG.10bb9edb3...@news.ecs.local>
stu...@cybervillage.co.ouch.uk (Stuart Halliday) wrote:

> > I have already seen things about ROM patches, using the wrong
> > version of HForm, ADFS buffer, DMA...
>
> Hform problems were due to 2GB+ drives.
> You've got the latest RISC OS ROM patches so ADFS buffers can be set to
> whatever you like.

Warning. This is not true.
I have a 6.5Gig IDE drive. With Riscos 3.7, with RomPatches 3.70/3.
If I have ADFSBuffers set to anything > 0 I get huge data corruption
problems.
This can be a problem when the Alsystems SCSI £ card arbitrarily resets
the ADFSBuffers for you when you run !Powermgr."
**************************

My own finding with RomPatch 3.04 with ADFSuffers >0 was that although my
RPC nolonger hung on occasions when assessing the large hard disc I still
found that there were occasional corruptions of files which I was not
aware of until I tried to use them later. Setting ADFSBuffers to zero and
this didn't happen. With OS 4.02 this was nolonger a problem.

If you have OS3.60, 3.70 or 3.71 it is sensible to instal RomPatch 3.04 as
it corrects a total of 9 problems. (Interestingly although the
documentation with it claims to cure the hanging with large hard disks it
does not mention and so does not claim to cure the corruption problem with
ADFSbuffer>0). I also read that although ADFSBuffers >0 could speed up
some file processes they could also slow down others depending on the file
size so setting ADFSBuffers >0 was not always beneficial even with smaller
disks

Alan

--
alan....@argonet.co.uk
alan....@riscos.org
Using an Acorn RiscPC

Chris Evans

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Aug 21, 2007, 6:05:54 AM8/21/07
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In article <e247c41...@itworkshop.invalid>, Jess

Re the patch, whilst it I don't think it was every released without the 'NOT
YET AUDITED' label, thousands of users used/use it without any problems
being reported.
The other work around of *con. ADFSBuffers 0 is more dangerous to use as
that will be lost by a power on delete and by the time you come to do one
you will most likely have forgotten that you need to to set
*con. ADFSBuffers 0 !


Chris Evans

--
CJE Micro's / 4D 'RISC OS Specialists'
Telephone: 01903 523222 Fax: 01903 523679
ch...@cjemicros.co.uk http://www.cjemicros.co.uk/
78 Brighton Road, Worthing, West Sussex, BN11 2EN
The most beautiful thing anyone can wear, is a smile!

Martin Longley

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Aug 21, 2007, 6:57:27 AM8/21/07
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In article <ant21105...@client.cjemicros.co.uk>,
Chris Evans <ch...@cjemicros.co.uk> wrote:

[Snip]

> Re the patch, whilst it I don't think it was every released without the 'NOT
> YET AUDITED' label, thousands of users used/use it without any problems
> being reported.
> The other work around of *con. ADFSBuffers 0 is more dangerous to use as
> that will be lost by a power on delete and by the time you come to do one
> you will most likely have forgotten that you need to to set
> *con. ADFSBuffers 0 !

So put an obey file containing *con. ADFSBuffers 0 in choices:boot.tasks

Martin Longley

--
mlon...@eclipse.co.uk

Message has been deleted

druck

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Aug 21, 2007, 1:10:07 PM8/21/07
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On 21 Aug 2007 Francis Devereux <fran...@gmail.com> wrote:
> I have ROMPatch 2.04 installed on my RISC OS 3.70 Risc PC with 6GB
> hard disc and am have ADFSBuffers set to 255. I have not had any
> problems with this so far but I might be living dangerously... has
> anyone else tried a similar setup and if so did it work?

It works, but its still dangerous to use ADFS buffers incase the disc
is accessed when the ROM patch isn't loaded, which may occur if there
is an error which terminates the boot sequence early, or it is skipped
all together via a shift boot.

Chris Evans

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Aug 22, 2007, 7:59:40 AM8/22/07
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In article <4f15ce674...@eclipse.co.uk>, Martin Longley

A very good idea but not ideal as it won't take effect until the second
reboot as it doesn't have immediate effect!

Theo Markettos

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Aug 22, 2007, 2:51:47 PM8/22/07
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druck <ne...@druck.freeuk.com> wrote:
> On Risc PC / A7000(+) hardware:-
>
> 3.5 or earlier : 512MB
> 3.6 and later : 128GB

I've summarised this thread for the FAQ here:
http://www.riscos.info/index.php/RISC_OS_FAQ#What_is_the_maximum_size_hard_drive_that_may_be_fitted_to_my_machine.3F

Please shout if anything is incorrect!

Theo

David Holden

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Aug 23, 2007, 1:39:51 AM8/23/07
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On 22-Aug-2007, Theo Markettos <theom...@chiark.greenend.org.uk> wrote:

One important point that should be mentioned is that although the filing
system supports large drives on RO 3.6 and above many 3rd party interfaces
may not. Some older interfaces may appear to work with large drives
formatted elsewhere but are unable to address more than about 20 GB due to
old style code which can lead to data corruption.

--
David Holden - APDL - <http://www.apdl.co.uk>

Stuart

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Aug 23, 2007, 2:08:36 PM8/23/07
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In article <5j4ktfF...@mid.individual.net>,

David Holden <black...@apdl.co.uk> wrote:
> One important point that should be mentioned is that although the filing
> system supports large drives on RO 3.6 and above many 3rd party
> interfaces may not. Some older interfaces may appear to work with large
> drives formatted elsewhere but are unable to address more than about 20
> GB due to old style code which can lead to data corruption.

Well, I presume my old but now upgraded Arcin is Ok with big drives ?

--
Stuart Winsor

From is valid but subject to change without notice if it gets spammed.

For Barn dances and folk evenings in the Coventry and Warwickshire area
See: http://www.barndance.org.uk

David Holden

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Aug 24, 2007, 2:36:58 AM8/24/07
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On 23-Aug-2007, Stuart <SW_N...@dsl.pipex.com> wrote:

> X-Postfilter: 1.3.35
> Xref: uni-berlin.de comp.sys.acorn.hardware:142207


>
> In article <5j4ktfF...@mid.individual.net>,
> David Holden <black...@apdl.co.uk> wrote:
> > One important point that should be mentioned is that although the filing
> > system supports large drives on RO 3.6 and above many 3rd party
> > interfaces may not. Some older interfaces may appear to work with large
> > drives formatted elsewhere but are unable to address more than about 20
> > GB due to old style code which can lead to data corruption.
>
> Well, I presume my old but now upgraded Arcin is Ok with big drives ?

I'm not certain but I believe the old single lead ArcIn may have the
problem. I know some of the early 2 socket ArcIns with IDEFS up to 3.23 did,
since that's when we discovered it (in those days most people with Acorn
machines measured their drive size in MB rather than GB).

Stuart

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Aug 24, 2007, 11:56:12 AM8/24/07
to
In article <5j7ckjF...@mid.individual.net>,
David Holden <black...@apdl.co.uk> wrote:

> I'm not certain but I believe the old single lead ArcIn may have the
> problem. I know some of the early 2 socket ArcIns with IDEFS up to 3.23
> did, since that's when we discovered it (in those days most people with
> Acorn machines measured their drive size in MB rather than GB).

Well having gone to the cost of upgrading I'll be a bit p****d off if it
doesn't work with my nice shiny new 80G drive which was the reason you
suggested upgrading!

Not tested yet due to other pressures!

Theo Markettos

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Aug 24, 2007, 5:24:25 PM8/24/07
to

Thanks, added. It's surprisingly complicated to summarise it all. If
anyone has details of maximum native formatted sizes for Simtec or Castle
USB, that would be useful. And did ST506 really have a 64MB limit? I've
heard that suggested, but don't know for sure. ISTR having a 170MB ST506
drive in a VAX once, but never tried it in an Acorn.

Theo

Andrew Wickham

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Aug 25, 2007, 9:46:40 AM8/25/07
to
In message <vNF*Im...@news.chiark.greenend.org.uk>
Theo Markettos <theom...@chiark.greenend.org.uk> wrote:

http://www.alasir.com/books/hards/039-041.html :

QUOTE
I have not seen any drives larger than 152MB (Modified Frequency Modulation
encoding) or 233MB (Run-Length Limited encoding) available for this type of
interface.
ENDQUOTE

The largest fitted as standard to an Archimedes was I think 53MB in the
A440/1, and I've heard the 64MB max elsewhere. RISCiX became SCSI-only
once the installation size exceeded the capacity of those drives. See
http://www.chiark.greenend.org.uk/~theom/riscos/docs/ultimate/a252unix.txt
:-)

Rgds,
Andrew

David Holden

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Aug 25, 2007, 10:55:42 AM8/25/07
to

On 25-Aug-2007, Andrew Wickham <ajw...@yahoo.co.uk> wrote:

> http://www.alasir.com/books/hards/039-041.html :
>
> QUOTE
> I have not seen any drives larger than 152MB (Modified Frequency
> Modulation
> encoding) or 233MB (Run-Length Limited encoding) available for this type
> of
> interface.
> ENDQUOTE
>
> The largest fitted as standard to an Archimedes was I think 53MB in the
> A440/1, and I've heard the 64MB max elsewhere. RISCiX became SCSI-only
> once the installation size exceeded the capacity of those drives. See
> http://www.chiark.greenend.org.uk/~theom/riscos/docs/ultimate/a252unix.txt

I have a couple of spec lists of most manufacturers old drive types and the
largest ST506 drive I could find was a Maxtor 5 1/4" FH drive of 196MB. Next
was a Rodime, also FH, of 178MB.

Stuart

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Aug 28, 2007, 5:17:24 PM8/28/07
to
In article <5j7ckjF...@mid.individual.net>,

David Holden <black...@apdl.co.uk> wrote:
> > Well, I presume my old but now upgraded Arcin is Ok with big drives ?

> I'm not certain but I believe the old single lead ArcIn may have the
> problem. I know some of the early 2 socket ArcIns with IDEFS up to 3.23
> did, since that's when we discovered it (in those days most people with
> Acorn machines measured their drive size in MB rather than GB).

Well, I've just installed it and formatted it OK but how can I be sure

KILL MICROSOFT FOREVER

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Aug 29, 2007, 7:08:23 PM8/29/07
to
In article <373ded174f%ajw...@yahoo.co.uk>, Andrew Wickham

<URL:mailto:ajw...@yahoo.co.uk> wrote:
>
> The largest fitted as standard to an Archimedes was I think 53MB in the
> A440/1, and I've heard the 64MB max elsewhere. RISCiX became SCSI-only
> once the installation size exceeded the capacity of those drives. See
> http://www.chiark.greenend.org.uk/~theom/riscos/docs/ultimate/a252unix.txt
> :-)
>
> Rgds,
> Andrew
>
53 Mb in a A440/1 ???
In my Archimedes A420/1 i have a 540 Mb Harddrive, working perfectly
In my BBC MAster 128 Turbo i have a 80 Mb harddrive in it, perfectly running.
and is 64Mb not the limit.
About the 256 Gb with RISC OS 4 is just a fairytale, you cannot go higher than
128 Gb !!!
Ask PM and he will confirm that.

Regards,
Simon

--
If you like Virusses, Worms, Security Flaws, choose for Microsoft

If you like to get rid of all those Virusses, choose for RISC OS
---

KILL MICROSOFT FOREVER

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Aug 29, 2007, 7:20:44 PM8/29/07
to
In article <vNF*Im...@news.chiark.greenend.org.uk>, Theo Markettos

<URL:mailto:theom...@chiark.greenend.org.uk> wrote:
> David Holden <black...@apdl.co.uk> wrote:
> >
> > On 22-Aug-2007, Theo Markettos <theom...@chiark.greenend.org.uk> wrote:
> >
> > > I've summarised this thread for the FAQ here:
> > > http://www.riscos.info/index.php/RISC_OS_FAQ#What_is_the_maximum_size_hard_drive_t
> hat_may_be_fitted_to_my_machine.3F
> >
> > One important point that should be mentioned is that although the filing
> > system supports large drives on RO 3.6 and above many 3rd party interfaces
> > may not. Some older interfaces may appear to work with large drives
> > formatted elsewhere but are unable to address more than about 20 GB due to
> > old style code which can lead to data corruption.
>
Sorry David,
On RISC OS 4 machines, you CANNOT go higher than 128 Gb Harddisc size and that
is a fact, Paul Middleton told me, he said, if ya wanna go higher, you have to
wait at least 5 years, he has than to change a lot of things on the adfs filer
and atm he is not doing that.
Actually very pity...hmmm than i have to look for a Apple MacPro then.

Cheers,

Bob Potter

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Aug 30, 2007, 3:36:47 AM8/30/07
to
"KILL MICROSOFT FOREVER" <nor...@datawave.nl> wrote in message
news:ant29232...@riscpc.stargate...

> 53 Mb in a A440/1 ???
> In my Archimedes A420/1 i have a 540 Mb Harddrive, working perfectly
> In my BBC MAster 128 Turbo i have a 80 Mb harddrive in it, perfectly
> running.
> and is 64Mb not the limit.
> About the 256 Gb with RISC OS 4 is just a fairytale, you cannot go higher
> than
> 128 Gb !!!
> Ask PM and he will confirm that.
>
> Regards,
> Simon

If PM will confirm that 256 GB with RISC OS 4 is a fairytale, RISC OS Ltd
should change their website where it says:
'One of RISC OS 4's most exciting features is support for large hard discs,
long filenames and a practically unlimited number of files per directory.
The maximum limit on size of hard disc is now 256 Gb'
http://www.riscos.com/risc_os_4/Features.htm

Bob

David Holden

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Aug 30, 2007, 4:39:48 AM8/30/07
to

On 30-Aug-2007, KILL MICROSOFT FOREVER <nor...@datawave.nl> wrote:

> In article <vNF*Im...@news.chiark.greenend.org.uk>, Theo Markettos
> <URL:mailto:theom...@chiark.greenend.org.uk> wrote:
> > David Holden <black...@apdl.co.uk> wrote:
> > >
> > > On 22-Aug-2007, Theo Markettos <theom...@chiark.greenend.org.uk>
> > > wrote:
> > >
> > > > I've summarised this thread for the FAQ here:
> > > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > >>>>>>>>>>>>>>http://www.riscos.info/index.php/RISC_OS_FAQ#What_is_the_maximum_size_hard_drive_t
> > hat_may_be_fitted_to_my_machine.3F
> > >
> > > One important point that should be mentioned is that although the
> > > filing system supports large drives on RO 3.6 and above many 3rd party
> > > interfaces may not. Some older interfaces may appear to work with
> > > large drives
> > > formatted elsewhere but are unable to address more than about 20 GB
> > > due to old style code which can lead to data corruption.
> >
> Sorry David,
> On RISC OS 4 machines, you CANNOT go higher than 128 Gb Harddisc size and
> that is a fact, Paul Middleton told me, he said, if ya wanna go higher,
> you
> have to wait at least 5 years, he has than to change a lot of things on
> the
> adfs filer and atm he is not doing that.
> Actually very pity...hmmm than i have to look for a Apple MacPro then.

Eh,and where, exactly, did I say that you *could* go bigger than 128GB?
Either you're replying to the wrong message or you haven't bothered to read
what I wrote.

Alan P Dawes

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Aug 30, 2007, 4:48:36 AM8/30/07
to
In article <13dcsu7...@corp.supernews.com>,

But in brackets aftewards it says:
(although only 18Gb has been tested)

Is Simon saying that since this was written ROS Ltd now tested over 128Gb
and 'it has been found wanting'?

druck

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Aug 30, 2007, 12:42:56 PM8/30/07
to
On 30 Aug 2007 "Bob Potter" <bob.p...@argonet.co.uk> wrote:
> If PM will confirm that 256 GB with RISC OS 4 is a fairytale, RISC OS Ltd
> should change their website where it says:
> 'One of RISC OS 4's most exciting features is support for large hard discs,
> long filenames and a practically unlimited number of files per directory.
> The maximum limit on size of hard disc is now 256 Gb'
> http://www.riscos.com/risc_os_4/Features.htm

There is a difference between what the OS can handle, and the hardware
limitations of certain machines such as the Risc PC, whoes motherboard
IDR interface is limited to 128GB. These limits may or may not exist
on other machines RO4 supports, or on Risc PC with 3rd party IDE
cards.

Theo Markettos

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Aug 30, 2007, 1:37:00 PM8/30/07
to
druck <ne...@druck.freeuk.com> wrote:
> There is a difference between what the OS can handle, and the hardware
> limitations of certain machines such as the Risc PC, whoes motherboard
> IDR interface is limited to 128GB. These limits may or may not exist
> on other machines RO4 supports, or on Risc PC with 3rd party IDE
> cards.

Are you sure it's a hardware limitation? The Risc PC IDE interface is dead
simple - a bunch of bus buffers and address decodes. It doesn't know
anything about hard drives, sectors, disc geometries or anything else - it
just decodes:
One 16 bit register at 0x03000000+(0x1F0<<2)
Six 8 bit registers at 0x03000000+(0x1F1<<2 to 0x1F7<<2)
One 8 bit regsiter at 0x03000000+(0x3F6<<2)
some read/write signals and an interrupt. It's up to the drive to respond
to read/write requests at these addresses - the Risc PC hardware has nothing
that generates data there.

On the drive 3.5 of those 8 bit registers provide 28 bits of sector
addressing (2^28*512bytes=128GB) in the conventional mode. When in 48 bit LBA
mode (necessary to access >128GB) only three of the 8 bit registers are
used, but the address must be written in two cycles of 24 bits (each
register is a 2-byte FIFO) - PDF page 64:
http://www.48bitlba.com/doc/specs/d1410r3-ATA-ATAPI-6.pdf

So as far as I can tell it's all software from the RPC to the drive -
actually it doesn't look too hard in principle to extend ADFS to do LBA48
addressing (but things don't always work to the standard, a bit like USB).
It /is/ a fairly good reason for ADFS to be limited to 128GB not 256GB
though. The hardware on other machines is more complex (eg the Iyonix's PCI
IDE controller) and non-ADFS filing systems may include support for LBA48.

Theo

Theo Markettos

unread,
Aug 30, 2007, 1:45:58 PM8/30/07
to
KILL MICROSOFT FOREVER <nor...@datawave.nl> wrote:
> In article <373ded174f%ajw...@yahoo.co.uk>, Andrew Wickham
> <URL:mailto:ajw...@yahoo.co.uk> wrote:
> >
> > The largest fitted as standard to an Archimedes was I think 53MB in the
> > A440/1, and I've heard the 64MB max elsewhere. RISCiX became SCSI-only
> > once the installation size exceeded the capacity of those drives. See
> > http://www.chiark.greenend.org.uk/~theom/riscos/docs/ultimate/a252unix.txt
> > :-)
> 53 Mb in a A440/1 ???
> In my Archimedes A420/1 i have a 540 Mb Harddrive, working perfectly
> In my BBC MAster 128 Turbo i have a 80 Mb harddrive in it, perfectly
> running. and is 64Mb not the limit.

Fitted /as standard/? We were talking about ST506 drives anyway - I bet
neither of those you have are ST506 drives.

It seems the Micropolis 1325 I used to use with my A3000 is listed as
somewhere between 69 and 80MB. But then I suppose the capacity depended on
the formatting in MFM days. (It was definitely MFM - I don't think Acorn's
ST506 controller did RLL?). I can't remember how much mine was formatted to
but think it was less than 64MB. It was done by Alsystems so they might
have obeyed some limit.

Theo

Hedley Hunnisett

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Aug 30, 2007, 5:10:01 PM8/30/07
to
In article <13dcsu7...@corp.supernews.com> "Bob Potter" wrote:

> RISC OS Ltd should change their website where it says:
> 'One of RISC OS 4's most exciting features is support for large hard
> discs, long filenames and a practically unlimited number of files per
> directory. The maximum limit on size of hard disc is now 256 Gb'

If that's really what they say, then they're talking about Gigabits, not
Gigabytes!

--
Hedley Hunnisett of Wigston Magna, Leicestershire.
Using British RISC technology with StrongARM power!

Theo Markettos

unread,
Aug 31, 2007, 7:26:32 AM8/31/07
to
Theo Markettos <theom...@chiark.greenend.org.uk> wrote:
> Six 8 bit registers at 0x03000000+(0x1F1<<2 to 0x1F7<<2)

Spot the deliberate mistake. There are /seven/ registers there (0x1F1-0x1F7
inclusive).

Theo

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