IBM compatible tape structure (*1) consists of a series of label blocks describing the volume and each file (Data Set). Essential the structure looks like this:
- VOL1..9 Volume header
- VOL1 Naming the Volume and optional owner (*2)
- HDR1..9 File header
- HDR1 Basically the directory entry for the file following
- HDR2 Description of the internal file structure like block length or record length
- Data Blocks
- EOF1..9 End of file markers
- EOF1/2 Basically a repetition of the HDR1/2 blocks
- [more files if present, covered by HDRx/EOFx blocks]
- EOV1/2 End of Volume markers in case of files spreading over multiple tapes
This structure is at least present since TOS/360 of 1964 and as well defined in a later ANSI standard (*3).
Has this structure been used before 1964 and which system or software did so?
(I'm prety sure it was, but I can't find any reference among my old manuals)
*1 - Essential disk structure as well.
*2 - Much like the Volume name entry of a MS-DOS 1.28 root directoy.
*3 - With some extensions like allowing larger block length than 80 bytes for labels.