[TUHS] PL/I stuff - was: Book Recommendation

Charles H. Sauer sauer at technologists.com
Sat Nov 27 10:47:49 AEST 2021

I haven't done anything with 9 track tapes for a long time, but I used 
to help my father with his statistical research, processing what at the 
time seemed massive census and similar data sets on 9 track tape (using 
PL/I on 370s at U. MO Columbia). Some of his tapes were quite old, 
stored in his basement and then his garage, but I don't recall problems 
reading any of them.

IMNSHO, it all depends on the brand/formulation of the tape. I've been 
going through old audio tapes and digitizing them 
Some are over 50 years old and still seem as good to me as when they 
were recorded. Others, I can anticipate from the brand/formulation that 
they are going to be trouble, if salvageable at all. Most surprisingly, 
unbranded and similar budget tapes have survived as well or better than 
some of the high-priced stuff. A few days ago I tried a reel from 1968. 
I was dismayed by how many times it had been spliced, but replace the 
splicing tape and found it viable.

I have dozens of DDS-2, 3 & 4 cartridges from the 90s that I 
occasionally try to read. I don't recall any of them failing.

(We probably should be COFFing this up.)


On 11/26/2021 6:30 PM, Larry McVoy wrote:
> On Fri, Nov 26, 2021 at 07:23:07PM -0500, Dennis Boone wrote:
>>   > In my experience 9 track tapes were not guaranteed to be readable after
>>   > some interval.  In fact, a standard operations procedure was to copy
>>   > important tapes to new media periodically.
>> There are always ways in which your backups can go wrong and not be
>> readable, and I'm not arguing that here.
>> But 9 track tapes have turned out to be pretty spectacularly long-lived.
>> I've personally read tapes that were stored for 30+ years in
>> unconditioned spaces.
> Contrast that with the write only exabyte tapes.  I lost some stuff to those.

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