Re: Couple more newbie questions.

Vern wrote:
Each record has in the first byte in storage, the flag for whether it is
deleted. I think it has the value, in hex, of C0 or 80 but it has been a
while. The difference there is 1 bit, on or off.


Vern -

Having written numerous O_SH*T programs to retrieve deleted records from files saved to save files (usually because some idiot deleted records that should not have been deleted), active records have an X'80' in the first byte, while deleted records have an X'C0' in the first byte.

The first such program that I wrote (in 1983, at a division of TRW in the Dallas area) was a program that recovered our MAPICS source from a S/38 multivolume diskette backup where the last diskette of the multivolume set had been overwritten by another library save (operator error, trying to conserve diskettes...).

Our IBM SE used a 5280 data entry system to repair the last good diskette of the backup and make it end of volume, and we were able to restore it as a database file.

I ended up writing a program that parsed through the data byte-by-byte to recover the source. Thankfully we had program listings for the program source that was lost (on the last diskette, which had been overwritten). We had to re-key the source for those programs from scratch.


- sjl