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Old 25 January 2022, 01:07   #1
graysters
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Request for clean adf (even just 1 sector) from legally owned 1.3.2 UK Workbench disk

Hi There!

I'm trying to restore my legally owned workbench disk (see attached image for proof!) to stock status, and was wondering if a kind soul would be able to share the adf for the following disk:
Workbench 1.3.2 U.K. P N 317789-03

The stock CRC32 for the untouched adf of this is apparently: C5692F06

Having compared and contrasted a few disk images I have come across, I have whittled down the differences to just 4 32bit words in the rootblock of the disk I have, which correspond to just the days, minutes and ticks of the last time the disk was accessed, plus the checksum of the rootblock sector where this block is stored... If anyone is interested, this is where they are stored (hex offset in adf):
0x6e016 - rootblock checksum
0x6e1da - days since last access
0x6e1de - minutes since last access
0x6e1e2 - ticks (50ms) since last access

so technically I only need the bytes from the above, if the whole adf can't be supplied!


I know it's not *that* big a deal to have these bytes different, but it would please me greatly to have a stock as possible workbench disk (that shall forever more remain write protected!!!)



Many thanks in advance!
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Old 25 January 2022, 10:53   #2
RetroPassionUK
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Quote:
Originally Posted by graysters View Post
Hi There!

I'm trying to restore my legally owned workbench disk (see attached image for proof!) to stock status, and was wondering if a kind soul would be able to share the adf for the following disk:
Workbench 1.3.2 U.K. P N 317789-03

The stock CRC32 for the untouched adf of this is apparently: C5692F06

Having compared and contrasted a few disk images I have come across, I have whittled down the differences to just 4 32bit words in the rootblock of the disk I have, which correspond to just the days, minutes and ticks of the last time the disk was accessed, plus the checksum of the rootblock sector where this block is stored... If anyone is interested, this is where they are stored (hex offset in adf):
0x6e016 - rootblock checksum
0x6e1da - days since last access
0x6e1de - minutes since last access
0x6e1e2 - ticks (50ms) since last access

so technically I only need the bytes from the above, if the whole adf can't be supplied!


I know it's not *that* big a deal to have these bytes different, but it would please me greatly to have a stock as possible workbench disk (that shall forever more remain write protected!!!)



Many thanks in advance!
Have you checked in the TOSEC collection for the disk?
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Old 25 January 2022, 12:55   #3
graysters
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Originally Posted by RetroPassionUK View Post
Have you checked in the TOSEC collection for the disk?
Thanks for the suggestion, but the only versions that I've seen available from the TOSEC collection are modified ones (denoted by [m]/[m2] etc), none I've seen are unmodified with the CRC32: C5692F06
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Old 25 January 2022, 16:36   #4
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Just made a quick GreaseWeazle image of mine:
the CRC = B2EEE771

And booting it I see what has changed (See Grab):

The Blue is Teal and the Pointer is Weird
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Old 25 January 2022, 17:14   #5
graysters
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Ha, yes, definitely a modded one! Mine was slightly more subtle, but the pointer was definitely not the right shade of red/orange

FWIW, The source of the crc32, and the belief that C5692F06 is the untouched original is from here:
http://webcache.googleusercontent.co...&ct=clnk&gl=uk

(originally compiled by MrDolby, cached as the original is sadly no longer available)
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Old 25 January 2022, 17:45   #6
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The actual URL works just fine for me: http://amiga.workbench.free.fr/workbench.php
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Old 25 January 2022, 18:19   #7
graysters
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The actual URL works just fine for me: http://amiga.workbench.free.fr/workbench.php
Oh, so it does! Definitely didn't yesterday, was throwing an error... thanks for the original link.
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Old 25 January 2022, 19:08   #8
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Originally Posted by graysters View Post
just 4 32bit words
If you can't find what you need, is practical to calculate backwards? I mean, there are a large number of values to test, but not infinite. Days must be a smallish number, say 50ish, minutes less than 1440, ticks less than 1200. Might be an overnight job, but if the CRC32 collision rate is low enough, you might end up with only one possible answer? Maybe?
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Old 25 January 2022, 19:26   #9
graysters
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If you can't find what you need, is practical to calculate backwards? I mean, there are a large number of values to test, but not infinite. Days must be a smallish number, say 50ish, minutes less than 1440, ticks less than 1200. Might be an overnight job, but if the CRC32 collision rate is low enough, you might end up with only one possible answer? Maybe?
That was exactly my thinking while poking around the adf image, but was hoping to shortcut 'yet another project' if someone had the adf and was willing to share... (my software skills are somewhat lagging behind my hardware skills!)
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Old 26 January 2022, 08:17   #10
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The ADF I made of my original 3.2.1 Workbench disk has exactly the CRC above you're referring to. The 4 bytes (in byte order) at each of the offests above are:

0x6e016 - 41 19 00 00
0x6e1da - 10 96 00 00
0x6e1de - 03 ab 00 00
0x6e1e2 - 08 f3 00 00

Hope that helps.
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Old 26 January 2022, 19:53   #11
graysters
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The ADF I made of my original 3.2.1 Workbench disk has exactly the CRC above you're referring to. The 4 bytes (in byte order) at each of the offests above are:

0x6e016 - 41 19 00 00
0x6e1da - 10 96 00 00
0x6e1de - 03 ab 00 00
0x6e1e2 - 08 f3 00 00

Hope that helps.
That's really helpful thank you... I've found that swapping sectors isn't as straightforward as I hoped, so might take a little longer to compile a 'clean image'...
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Old 27 January 2022, 17:25   #12
graysters
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Having spent far too long swapping sectors and fixing checksums on the sectors that I know were modified on my disk... I now realise that the source for the assumed 'untouched' sectors, from adfs already out there are not actually untouched... So I'll never get it to match that way...

I was working on the assumption that sectors that were identical in more than one image file meant that they couldn't have been changed from the original... but it turns out that one of the two images I was working from must have been copied from the other at some point in it's history, so sadly not untouched.




Could someone put me out of my misery and PM me the Workbench 1.3.2 U.K. P N 317789-03 ADF with CRC: C5692F06 (Proof of ownership of the original disk in first post)

Many thanks
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Old 27 January 2022, 21:17   #13
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Could someone put me out of my misery and PM me the Workbench 1.3.2 U.K. P N 317789-03 ADF with CRC: C5692F06 (Proof of ownership of the original disk in first post)
Yo from Cambridge!

I dug around and found these.



I'll put them through a Greaseweazle or something now.

I have no idea if any or all are modified mind.
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Old 27 January 2022, 21:27   #14
graysters
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Thanks matburton... but I'm sorted as of a few minutes ago thanks to Exodous!

really appreciate the support guys!
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Old 27 January 2022, 21:44   #15
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OK all three look like they haven't been written to by an Amiga judging by alignment.





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Old 27 January 2022, 21:44   #16
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Thanks matburton... but I'm sorted as of a few minutes ago thanks to Exodous!

really appreciate the support guys!
Ah cool sorry I didn't refresh lol
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Old 27 January 2022, 23:33   #17
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Still worth imaging them, matburton!
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