[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 
(https://notes.technologists.com/notes/2021/08/21/making-private-1960s-and-70s-recordings-public/). 
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.)

Charlie

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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