Hi there,

Could someone explain to me how double-sided discs are arranged in a .DSD disc image?

I read somewhere that they are interleaved, but I couldn't find much more than that. If that is the case, are they interleaved sector by sector (e.g. side 0 sector 0, side 2 sector 0, side 0 sector 1...), track by track or by some other means?

Kind regards,

Francis.

Okay, based on some quick tests I've done it looks as though they are interleaved track by track.

Could someone please confirm this so I don't end up with any nasty surprises?

Thanks!

Kind regards,

Francis.

Yes that's right.

Francis,

I'm not sure if the .dsd file is actually explicitly specified anywhere. I think you're correct in that it is interleaved. There are some notes here:

http://mdfs.net/Docs/Comp/BBC/FileFormat/Imgnotes

I think you *may* find that some older tools like BBC Explorer or FDC might handle images slightly differently. Going with the BeebEm route is probably a good bet.

Jason Watton may be a good guy to email about it - he wrote OmniFlop which handles many of the beeb image formats and is probably well up on what standards exist.

Sam.

Thanks guys.

@Samwise
Those notes look like the ones I was originally looking at.

The BeebEm route is the one that I will be going down (at least initially) since this is the tool I use for testing disc images that have been manipulated with my BBC Micro Image Converter and verifying that there are no problems. If anyone has problems with compatibility with other tools then I can look at that later on.

Kind regards,

Francis.