In the interest of the historical pats of this hobby,? having such a device available to use in Hercules might not be a bad idea, (...or maybe it is as I am speculating).? It’s not an autotape library, but it's an auto dasd library of 3330's in appearance to MVS, the support for the device is apparently in the OS already, so it’s a single address and provides a selection of 3330 volumes.? - Admittedly small in size by today's standards, but the allocation in the underlying Linux disk system is not overly large, the mechanical aspects would not exist as it's all software as a Hercules device.

So the issues relating to this at the time being cumbersome and prone to breakage were all in the mechanical aspect, and it would no doubt be faster in operation.

Now I have no idea the effort required to create such a device, and assume one would need to have allocated the entire disk space at the time of creation of this MSS device when adding it to a config file.? ?But it might be interesting to have. The whole allocation is not that excessively large given our host system disk space available. I mean seriously, a Tb is trivial anymore.

What are the thoughts of others?? ? I would not be capable at the moment of creating this addition to Hercules itself to allow it to be allocated, and that may be a huge task for all I know it is.? ?This is a question to the developers of Hercules and they no doubt have many competing priorities, this would be low priority.

But it might be nice to have it none the less, as a historical artifact, still useful, ecpically since the mechanical issues would not exist.? For those using MVS 3.8.? ? It truly was a good idea at the time, and of course disk sizes and technology has passed it by, but so has technology passed by a lot of this and we still play with it.


What's anyone think?


Dave,
N8ZFM, Louisville, KY
dave@...? ?dave40272@...


?On 2/7/25, 11:23 AM, "[email protected] <mailto:[email protected]> on behalf of Charles Bailey" <[email protected] <mailto:[email protected]> on behalf of txlogicguy@... <mailto:txlogicguy@...>> wrote:


When I worked for IBM in Tucson, AZ, in the early 1980's, much of our
data was stored on MSS. When we would run a foreground job from TSO,
the application would typically output a message like: "Allocating
datasets, please be patient". That is because executing a statement
like "ALLOC DD(xxxx) DSN(xxx.yyy.zzz)" took a half minute to a full
minute to execute. The MSS monstrosity was amazing to watch in
operation. It consisted of a wall of honeycomb-like compartments where
the tapes were stored. The operation of the whole contraption was
mostly transparent to the user. The command to allocate a dataset would
cause the picker to locate the honeycomb location where the tape was
stored, retrieve it, and mount it on a device that emulated a DASD. I
don't think the tape was copied to a real DASD. Data was read from and
written directly to the tape, which was quite wide. I think each
vertical (crosswise) stripe on the tape emulated a DASD track. When a
FREE command was executed, the tape would be rewound back into the
cartridge and the picker would put it back into the honeycomb. I'm not
sure if any special support would be required from Hercules. I think
the VOLSER of the tape appeared to the OS as just another 3330 DASD.
(This is all from my distant memory of conversations with older
engineers would used to work on the beast. I'm sure an internet search
would yield a much better description.)


Charles Bailey


On 2025-02-07 00:21, Dave Trainor - N8ZFM wrote:
> So I am studying the OS JCL and Utilities book (Michael Trombetta) from the mid 80's, good book ,was recommended to me for the MVS 3.8j era of JCL. Am happy with it and can also recommend it.
>
> They discuss utilization of the MSS storage device(s) a 3850, and at the mid 80's of the book it was a current device, seems to consist of a 3330 disk (maybe more than one) and a series of tape carts, with an "invisible" autoloader system, so as to implement "near-line" storage. Only one actual dasd and a bunch of different images of it on tape, that would be recalled by the VOLSER from MVS and loaded on the live DASD where it was then a live 3330 disk. (obviously a delay in preforming this "staging operation" as I take it was called).
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> Probably more complicated in reality but that is my gist of the functionality. Different logically but easier than mounting a tape, doing a restore, then archiving, not as fast as having dedicated DASD.
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> I assume since I can't find it in Hercules, that this device and not sure to call it tape or disk - is not emulated by Hercules, probably would not be useful and no one uses any such scheme since the mid 80 As the need probably got replaced quickly by vastly larger amounts of cheap DASD being available? Anyone know? Or remember these things and why they are obscure today?
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> I do not see this as being the same functionality as a backup tape library (automounter) of true tapes treated as tapes which is for sure still being utilized.
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> Is my assessment of what this 3850 MSS device was correct? And why we don't have an emulation for such a thing anymore?
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> Thanks,
> Dave N8ZFM
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