[Info-vax] Hobbyist licences for VAX

[gah4]

On Friday, April 15, 2022 at 4:51:27 AM UTC-7, David Wade wrote:

(snip, I wrote)

> > They do implement it, but IBM and Hercules implement it in a different way. 
> > I think it is only one bit somewhere that is in a different place.

> I don't believe there is any difference EXCEPT Hercules supports 
> compressed images and also shadow files. Certainly files from my P390 
> work under Hercules.

As long as they don't use track overflow, that is, actually write tracks using it,
you don't notice the difference.  As well as I know, the only problem is in the
paging file for MVS, and only on devices that support track overflow.

I had thought it was only 2314 and 3330, but the above suggests 3340.
As well as I know (it was years ago when I thought about this) it is
not on the 3350, 3380, or 3390. 

And yes, Hercules also has compression and shadow files. 

I did install MVS on a P/370 using the files from Hercules, but I had
to do it from the install (virtual) tapes.  Also, you have to change one
bit in control register 0.