OPD format: Difference between revisions
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== OPD file structure == | == OPD file structure == | ||
OPD images can store single or double sided 40 track disk images, but most of the files are single | OPD images can store single or double sided 40 track disk images, but most of the files are single sided 40 track disk images. | ||
=== File Header === | === File Header === | ||
Latest revision as of 21:21, 23 July 2015
OPD Disk Image Format
The OPD format was created for storing Opus Discovery disk images for emulation.
This format is member of the Easy Disk Image Formats and contains only the data of sectors.
OPD files sometimes have .opu extension.
OPD file structure
OPD images can store single or double sided 40 track disk images, but most of the files are single sided 40 track disk images.
File Header
There is no any header or file signature (magic bytes).
Data
Sectors laid from 1st to last within a track:
- Sector 1
- Sector 2
...
- Sector last
Tracks in file
Track data follow the “alt” schema:
- Side: 0 Track: 0
- Side: 1 Track: 0
- Side: 0 Track: 1
...
- Side: 0 Track: 39
- Side: 1 Track: 39
File length
Opus Discovery uses 256 BPS and 18 SPT for disks (see Opus Discovery), so a
- 40 track 1 sided image length is 184320 byte (1×40×18×256)
- 40 track 2 sided image length is 368640 byte