[Info-vax] History question about ODS-1

[Jon Pinkley]

On Monday, July 29, 2019 at 4:42:56 PM UTC-4, Lee Gleason wrote:
---snip---
>   It looks to be a size problem - apparently VMS 7.3 only supports ODS-1 
> volumes up to a certain size. This is an RA92 ODS-1 disk image, from an RSX 
> system, which is apparently too big for VMS. I'm basing this guess on the
> 
> %INIT-F-LARGECNT, disk too large to be supported
> 
> message I get when I try and INIT an RA92 as ODS-1 using the /STRUCT=1 
> switch.
> 
> --
> Lee K. GLeason N5ZMR

I saw the INIT and didn't even notice you said this was "an RA92 ODS-1 disk
image, from an RSX system"

So evidently, if it was working on an RSX system, there must have been changes
to RSX since 1981 that allowed "large disks".

If that happened, it is unlikely that the change ever got ported to VMS.

But Rob Brooks may be able to ask Andy if he remembers.

http://bitsavers.trailing-edge.com/pdf/dec/pdp11/rsx11/Files-11_ODS-1_Spec_Apr81.pdf

pg 2 in summary of changes mentions limit of 1,044,480 max blocks, but on page 3
it talks about theoretical size limits "232 blocks", which I think should have
been 2**32 blocks, and then says current implementations are limited to 
"224 blocks" (assuming that meant 2**24).  This may have been a document that had both ODS-1 and ODS-2 info mixed together.