Post #186551
2026-01-30 15:50 UTC
The second thing I've been doing is trying to figure out how ARCHIV (roughly equivalent to 'tar') works and therefore how to interpret the file format. This is the file format for most of the preserved source code (which is fortunately pretty readable without understanding the details), but the preserved files also include two versions of the utility itself.
4/n
#CTSS #retrocomputing #IBM7094
Replies (1)
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@philcowans@universeodon.com 2026-01-30 15:54
The earlier version is from 1968. The key thing is the format of the 'super line mark', which is the separator between the various files in the archive. The 1968 version has the following comment describing how it works: THE FORMAT OF THE 'SUPER LINE MARK' IN ARCHIV FILES IS: 777777000000K,..,..,..,777777000011K,FLN1,FLN2, $ MM/DD/YY HHMM.M $, $ZZZZZZ$,$$,$ 000$,$00 $ TOTALLING 14 WORDS, WHERE ZZZZZZ IS FILE WORD COUNT. THIS INFORMATION SHLD NOT BE KNOWN ANYWHERE IN THE PROGRAM EXCEPT IN THE FLLWING INTERNAL FUNCTIONS AND V'S STATEMENTS. This describes a #BCD format (6x 6 bit characters per 36 bit word). 5/n #CTSS #retrocomputing #IBM7094