On Sat, 16 Dec 2017, Aaron Jackson via cctalk wrote:
The ones
labelled RT-11 don't actually have RT-11 on them, just some random
files, and these were the ones I had tried to boot from.
Yep.
Being labelled "RT-11" does not mean that they have RT-11 on them.
They could be Compupro disks from the accounting department, containing
the bookkeeping/invoices for the RT-11 system.
They could be disks from a writer containing a manuscript for an
instruction manual for RT-11.
They could be transportation department disks relating to Route 11 between
Louisiana and New York.
They could be Robert Thompson's disk from 2011. Or just disk #11 of his
set.
Or "Russia Today"
Or the IBM "RT PC"
Or "Real Time", . . .
Long ago, we had an "interesting" series of discussions here, when
somebody claimed to have OS/2 on a PDP! They were apparently PDP disks
labelled "OS/2". (He also told us that FORTRAN was based on Valtrep
(1990s); that his 1990s Sun computer was the first computer used for
e-mail; and he asserted that his "copy everything" program could copy
alignment disks.)
When people "need" a blank disk, and none are handy, they might use
ANYTHING. Therefore, even disks with factory labels identifying them as
system installation disks don't necessarily have that on them, nor even
that they are in the format expected for the machine.
We once had a "technician" in the school computer lab reformat several
boxes of disks, because the machine that he tried them in couldn't
read them, without even realizing that they were a different digk
format for a different machine!
So, some of us do not trust the labels on disks.
