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RE: Old PDP11 Tapes
At 04:10 PM 8/30/1999 -0400, Bob & Cecelia wrote:
>The second step would be to actually read the tape image files under
>Hopefully you remember how the tapes were made. I am especially foggy
>comes to all of the backup programs that we had on Delta.
If the tapes were created by DEC's BACKUP or PIP programs, those are
included with the simulator. Once you've copied the tapes into a file
that the simulator can access, then you should be able to simply read
them directly. (This assumes that the tapes were originally created under
RSTS V7 or earlier.)
Most of Delta's tapes were created with a homebrew program called
FAILSAFE. If we ever got to the point of being able to copy Delta tapes
into a simulator file, I think I have a hardcopy of the source code of
FAILSAFE somewhere that could be used to decipher the file format.
If all else fails, assuming that what the tapes contain is ASCII source
code and documentation (i.e. not compiled programs), once you've got them
copied into a disk file you might just be able to read them by brute
force using an ordinary text editor (maybe even Windows Notepad) and
stripping out the garbage between files by hand.
FYI, some friends recently discovered a reel-to-reel audiotape I made in
college that had been stored in a non-climate-controlled basement for 15
years. Parts of it were "readable" and parts were not. After 15
years the oxide starts coming off the plastic tape. This was reasonably
high-quality audiotape, but I don't know how it compares to computer tape
in terms of robustness.