CD-ROM on RT-11?

From: Jerome Fine <jhfine_at_idirect.com>
Date: Fri Mar 15 18:27:14 2002

>Tom Leffingwell wrote:

> >On Tue, 12 Mar 2002, Zane H. Healy wrote:
> > Yes, it is possible. The real trick is finding a SCSI CD-ROM that will work
> > with your SCSI Adapter! In my case I'm using a Viking QDT with a DEC RRD-42
> > drive (I think that's the right drive, it's the one that uses standard
> > caddies).
> Yeah, the RRD40 was the one with the special DEC caddies where you never
> had to touch the CD. I think I still have one somewhere. RRD42 used the
> standard caddies, and was double speed I believe. RRD43 was the one where
> the disk snapped into it, and the RRD45 was the 4x speed tray one, and the
> RRD46 was the 12x speed tray one. I'll have to see what I have. Its more
> than likely going to be an RRD43 though, but I would think it would work.

Jerome Fine replies:

Can anyone recommend an ordinary CD that will work with
a CQD 220/TM?

Also, while the normal ISO file structure probably will NOT
easily allow (if at all) RT-11 partitions to be written on 65536
block boundaries, for RT-11, that is essential.

Zane, have you solved that problem? Which operating system
do you use? Can it also be done under Windows 98?

I understand that it might be possible to use the "dd" from Unix
with a version that has been set up to run under Windows 98.
Has anyone heard of this? I am running Windows 98 with
a Pentium III 750 and 512 MBytes of memory and a 40 GByte
EIDE hard drive.

Since I use E11 to run RT-11 under Windows 98, it is not
critical to have RT-11 partitions, but it would be very nice.

> > I feel a lot safer being able to restore from CD's rather than old
> > flakey TK50's. Basically you just burn a disk image of a HD that's
> > been built on that controller to a CD-R. I've done this for RT-11,
> > RSX-11M, and RSX-11M+. Of the three RT-11 complains the least about
> > being on CD. The two RSX's I tried *really* don't like it, but appear
> > to come up enough that I should be able to copy them to a real HD.
> I may give this a shot then. I think its my best option.

I gave up on a TK50 for backup as soon as I found it took
over an hour to "/VERIFY:ONLY" just one RT-11 partition
under BUP. Since I use the same tapes on a TK70 (after
being bulk erased) and the TK70 is 3 times as fast in writing
and the tape can hold 4 times the number of MBytes, there
did not seem to be a choice between the TK50 and TK70.
Plus, with a TK70, the "/VERIFY:ONLY" of an RT-11
partition takes the same time as writing it. Of course, with
EIGHT RT-11 partitions on one tape, it sometimes takes
a long time to find the RT-11 partition.

As for using the CD as backup for PDP-11 files, I strongly
agree. My goal is to be able to find a CD-ROM drive that
I can put on my CQD 220/TM and then boot RT-11 from
partition zero. Note that since I almost always boot RT-11
from an ESDI hard drive which is in WRITE PROTECT
mode (a hardware selection via a jumper), the only problem
I see is being able to read the first 64 blocks of the CD on
partition zero - and of course setting up an RT-11 partition
starting at block zero of the CD.

Has anyone solved these two problems?

Sincerely yours,

Jerome Fine
Received on Fri Mar 15 2002 - 18:27:14 GMT