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General Category => Emulators => Topic started by: leibnitz27 on 09:57, 09 October 12

Title: Disk image layout - is there a doc?
Post by: leibnitz27 on 09:57, 09 October 12
Hi All -
 
So I'm messing around with getting back into CPCs, and one thing I'd like to do is understand the layout of a CPC disk image, by just writing something in C to look at files on a DSK (but without doing a full blown emulator!!  ;D )
 
The file format for the DSK image shows me how the physical data is laid out, Format:DSK disk image file format - CPCWiki (http://www.cpcwiki.eu/index.php/Format:DSK_disk_image_file_format) , which is great, but are there any docs as to how a DATA formatted disk is laid out given this? 
 
When I've been digging, I keep on ending up at "get the catalog by calling CAS CATALOG (BC9B)" Unofficial Amstrad WWW Resource (http://www.cpctech.org.uk/docs/catalog.html) - what I'd like is - has anyone documented the equivalent of the FAT, so I can do this by hand without firmware present?   (I'd look at eg the source for CPCloader, but it doesn't seem to be open source :(  , unless I've missed something really obvious! :)  )
 
Cheers!
 
Title: Re: Disk image layout - is there a doc?
Post by: arnoldemu on 11:44, 09 October 12
Hi All -
 
So I'm messing around with getting back into CPCs, and one thing I'd like to do is understand the layout of a CPC disk image, by just writing something in C to look at files on a DSK (but without doing a full blown emulator!!  ;D )
 
The file format for the DSK image shows me how the physical data is laid out, Format:DSK disk image file format - CPCWiki (http://www.cpcwiki.eu/index.php/Format:DSK_disk_image_file_format) , which is great, but are there any docs as to how a DATA formatted disk is laid out given this? 
 
When I've been digging, I keep on ending up at "get the catalog by calling CAS CATALOG (BC9B)" Unofficial Amstrad WWW Resource (http://www.cpctech.org.uk/docs/catalog.html) - what I'd like is - has anyone documented the equivalent of the FAT, so I can do this by hand without firmware present?   (I'd look at eg the source for CPCloader, but it doesn't seem to be open source :(  , unless I've missed something really obvious! :)  )
 
Cheers!
DATA, SYSTEM and IBM are all variants of the CP/M filesystem.

DATA has no system tracks, SYSTEM has 2 system tracks.
The directory blocks follow.

This is a good reference:
CP/M information archive : disc formats (http://www.seasip.demon.co.uk/Cpm/format22.html)
CP/M information archive : disc formats (http://www.seasip.demon.co.uk/Cpm/amsform.html)


Title: Re: Disk image layout - is there a doc?
Post by: leibnitz27 on 13:25, 09 October 12
Great, thanks!
Title: Re: Disk image layout - is there a doc?
Post by: arnoldemu on 15:14, 09 October 12
Great, thanks!
you're welcome :)