>> 2. The RSX-11 CD-ROM. The sum total of stuff here comes very near
>> 650 Mbytes, so it's not possible to have "dual-format" stuff here.
>> So I propose three different flavors:
>>
>> 2A: An ODS-1 (i.e. native RSX-11 format) CD-ROM. Only useful to
>> those with a CD-ROM drive hooked up to a real PDP-11, or to those
>> using John Wilson's full-blown E11 emulator.
>Can OpenVMS 7.2 read ODS-1, and if so does this require a VAX or will it
>work on a Alpha.
*That's* a long story. Let's set the wayback machine back
to 1974 or so, when RSX and ODS-1 was developed. At that point in time, the
ODS-1 definition allowed for disks up to 512 Mbytes in size. That
wasn't a problem at the time, as the disks it was being developed on
were, at most, 2.5 Mbytes or 5 Mbytes.
Then, in 1976/77/78, early VMS development started - at first on an
emulator running on a PDP-11/70. The first VMS versions only supported
ODS-1 disks, but then "ODS-2" was developed and became the mainstay
shortly after official release.
A few years after that, larger disk drives began becoming available.
The RSX-11 folks updated their definition of ODS-1 to allow for drives
larger than 512 Mbytes, but the VMS folks didn't.
The chasm between "RSX-11 ODS-1" and "VMS ODS-1" has widened since.
Alpha/VMS has never supported ODS-1 volumes, largely because nobody at
DEC ever went to the trouble of putting support in. And the RSX-11
ODS-1 definition has grown even more, to allow drives much larger
than 8 Gbytes to be usable on modern RSX-11 systems.
The RSX-11 CD-ROM is, in size, well over 512 Mbytes and as a result
can't even be mounted on a VAX/VMS machine as an ODS-1 volume, because
current versions of VMS don't support the extensions to get over
512 Mbytes. And Alpha/VMS simply refuses to even try to mount any
ODS-1 volume.
Now, I'm currently involved in a project, spearheaded by me and a few
RSX oldtimers who have kept current on Vax/VMS and Alpha/VMS developments,
for "regularizing" ODS-1 support across RSX-11, VAX/VMS, and Alpha/VMS.
We have offers of assistance from insiders in DECpaq's VMS Engineering,
as well as the official ODS-1 spec. As a result, support for ODS-1 in
both VAX/VMS and Alpha/VMS will be improved soon, if everything works
as planned. (And all those involved have enough Copious Free Time
to implement the details.)
>> 2B: An ISO9660 CD-ROM filled with RSX-11 virtual disks. These would
>> be useful to folks who could Kermit or FTP the logical disks to
>> a real RSX-11 machine with a virtual disk driver, or to those
>> running John Wilson's full-blown E11.
>Hmmm, doesn't this require a fairly new version of RSX-11? For hobbyists,
>this is likely to be a problem. I know the version I've got doesn't support
>virtual disks.
I think that Mentec officially introduced support for virtual disks
and virtual tapes beginning with 11M+ V4.5 - yes, fairly recent.
>Although, I seem to recall there is a DECUS program to allow this...
Yep, there is a freeware virtual disk driver that works under 11M+
(but not, AFAIK, under 11M).
--
Tim Shoppa Email: shoppa_at_trailing-edge.com
Trailing Edge Technology WWW: http://www.trailing-edge.com/
7328 Bradley Blvd Voice: 301-767-5917
Bethesda, MD, USA 20817 Fax: 301-767-5927
Received on Thu Jul 29 1999 - 11:39:24 BST