The SCL format is a compact representation of TR-DOS filesystem content. It stores only the file headers and the used sectors.
It is conventional for emulators to build real disk images on the fly from SCL data to use for disk emulation.
SCL file structure
The file begins with a 8 byte 'magic': SINCLAIR, then the number of files, the file headers an after that all the data blocks.
Offset Length Comment 0x0000 9 SCL file header 0x0009 N × 14 File headers 0x0009 + N × 14 DATA LENGTH Sector data
SCL file header
Offset Length Comment 0x0000 8 Signature "SINCLAIR" 0x0008 1 Number of files (N)
Offset Length Comment 0x0000 14 1st file header entry 0x000e 14 2nd file header entry ... ... ... 0x0000 + (N-1) × 14 14 Nth file header entry
File header entry
The file headers structure is the same as in the TR-DOS filesystem, except the last two bytes (start sector, start track).
Offset Length Comment 0x0000 8 File name 0x0008 1 File type 0x0009 3 File parameters (based on type) 0x000d 1 File length in sectors
Offset Length Comment 0x0000 1st file length × 256 1st file data 0x0000 + 1st file length × 256 2nd file length × 256 2nd file header entry ... ... ... 0x0000 + .... last file length Nth file header entry