Print Page - "EXTENDED CPC DSK File" (.dsk) format

Title: "EXTENDED CPC DSK File" (.dsk) format
Post by: Wanderer on 22:49, 16 February 10

Hi everyone.

Could someone please point me to info about the .dsk file format? I know i've seen it somewhere but i can't find it at the moment.

Thanks

Title: Re: "EXTENDED CPC DSK File" (.dsk) format
Post by: redbox on 23:31, 16 February 10

They are on the 'Unofficial Amstrad WWW Resource' website (www.cpctech.org.uk):

Normal DSK format (http://www.kjthacker.f2s.com/docs/dsk.html)

Extended DSK format (http://www.kjthacker.f2s.com/docs/extdsk.html)

Title: Re: "EXTENDED CPC DSK File" (.dsk) format
Post by: Wanderer on 23:36, 16 February 10

Quote from: redbox on 23:31, 16 February 10'Unofficial Amstrad WWW Resource' website (www.cpctech.org.uk)

Great. Thanks. I have found several links to the 'Unofficial Amstrad WWW Resource' on Google but they all pointed to a dead site.

Title: Re: "EXTENDED CPC DSK File" (.dsk) format
Post by: redbox on 23:56, 16 February 10

Quote from: Wanderer on 23:36, 16 February 10
Great. Thanks. I have found several links to the 'Unofficial Amstrad WWW Resource' on Google but they all pointed to a dead site.

Yes, cpctech.org.uk is a frame mask for: http://www.kjthacker.f2s.com/

Title: Re: "EXTENDED CPC DSK File" (.dsk) format
Post by: Devilmarkus on 00:26, 17 February 10

The actual website can be found here:
http://arnold.cpc-live.com/cpctech/
(mirror)

Title: Re: "EXTENDED CPC DSK File" (.dsk) format
Post by: krusty_benediction on 22:10, 09 December 18

Just looked at these documentation to write a DSK reader for my toolbox. I have to admit that I do not find them clear at all.For example, location of data is not explicitly stated. I had to make several tries before (I hope so) being able to write my DSK reader (at least the sector information looks like what cpcpower view for the dsk I tested).
The ultimate fix to my code was to start to read the the sector data after 231 bytes. I obtain this magic number there : https://github.com/damieng/DiskImageManager/blob/master/Source/DSKFormat.pas#L37 (I doubt i would have been able to finish my reader without that)
Why this value ? I do not understand at all; it is not even a multiple of 8.
Thanks for the help

Title: Re: "EXTENDED CPC DSK File" (.dsk) format
Post by: robcfg on 23:08, 09 December 18

I did a DSK file reader, and I don't have any fixed values.

See here the C++ declaration of that data structure on my code:

Code Select

struct CDSKFile_TrackInfoBlock
{
	string header;                              // Header string is 13 bytes long
	unsigned char unused[3];                    // 3 unused bytes
	unsigned char trackNumber;                  // Track number
	unsigned char sideNumber;	            // Side number
	unsigned char dataRate;                     // Previously unused. Now Data Rate (John Elliott extension)
	unsigned char recordingMode;                // Previously unused. Now Recording Mode (John Elliott extension)
	unsigned char sectorSize;                   // Sector size
	unsigned char sectorsNum;                   // Number of sectors
	unsigned char gap3Length;                   // GAP#3 length
	unsigned char fillerByte;                   // Filler byte value
	vector<CDSKFile_SectorInfo> sectorInfoList; // Sector information list
	vector<uint8vector> sectorData;             // Actual sector data
	bool isUnformatted;                         // Is this an unformatted track?
};

Hope it helps!

Title: Re: "EXTENDED CPC DSK File" (.dsk) format
Post by: krusty_benediction on 09:51, 10 December 18

Code Select

Not really I have well understood this global structure.
To undetrstand where I fuck(ed) up, I would need to see your bits of code just after reading 
sectorInfoList [font=arial]and just before reading [/font]sectorData. [size=2][font=arial]I started to read at a wrong place (i have not verified if it is too soon or too late however) until I used this 231 magic number.

thxedit: what a crappy web editor ...

Title: Re: "EXTENDED CPC DSK File" (.dsk) format
Post by: Gryzor on 13:46, 13 December 18

Quote from: krusty_benediction on 09:51, 10 December 18thxedit: what a crappy web editor ...

Just use the 'Remove Formatting' button ;)

Title: Re: "EXTENDED CPC DSK File" (.dsk) format
Post by: krusty_benediction on 22:04, 17 December 18

Fixed the issue few days ago .I do not remember where I was wrong, but I use no more this hard coded value

Quote from: robcfg on 23:08, 09 December 18I did a DSK file reader, and I don't have any fixed values.

See here the C++ declaration of that data structure on my code:
Code Select Expand
struct CDSKFile_TrackInfoBlock { string header; // Header string is 13 bytes long unsigned char unused[3]; // 3 unused bytes unsigned char trackNumber; // Track number unsigned char sideNumber; // Side number unsigned char dataRate; // Previously unused. Now Data Rate (John Elliott extension) unsigned char recordingMode; // Previously unused. Now Recording Mode (John Elliott extension) unsigned char sectorSize; // Sector size unsigned char sectorsNum; // Number of sectors unsigned char gap3Length; // GAP#3 length unsigned char fillerByte; // Filler byte value vector<CDSKFile_SectorInfo> sectorInfoList; // Sector information list vector<uint8vector> sectorData; // Actual sector data bool isUnformatted; // Is this an unformatted track? };

Hope it helps!

Title: Re: "EXTENDED CPC DSK File" (.dsk) format
Post by: robcfg on 22:07, 17 December 18

That's great news!

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General Category => Emulators => Topic started by: Wanderer on 22:49, 16 February 10