Microvax II

From: Jerome Fine <jhfine_at_idirect.com>
Date: Sat Oct 14 23:10:51 2000

>ajp166 wrote:

> >Anyone out there who wants to try? I would be very pleased to
> >swap some of my time for a couple of SCSI 32 GByte hard drives
> >to test out the software. The only problem is that the only SCSI
> >host adapters I have are the 50 pin type (CQD 220/M), so there
> I've run my PDP11 with SCSI CQD already as it's MSCP, Same
> for VAX/VMS (it's in my MVII).

Jerome Fine replies:

It seem like we agree. The question I was asking was whether or not
SCSI-2 drives with the 50 pin interface are made that have a capacity
of more than 9.2 Gbytes such as the ST410800N - preferably at
least 16 GBytes are maybe even 32 Gbytes. Since I already know
about this Seagate drive and I agree that is is reasonable in cost, it
is the larger drives that I am asking about - sorry if I was not clear
as to the question.

> It's limited to 4 or 8gb and SCSI-II so forget the reall monster drives.

Are you sure? Is anyone aware of larger drives that still use the 50 pin
SCSI-2 interface?

> The idea of such huge drive with RT11 and friends is that is wasted.
> I use D540s (31mb) and swap them like carts as I have a bunch of em
> and they are plenty big enough. Drives in the 120-400MB range are
> plentyful for me, one 200mb drive would take all the binaries and
> sources I have with room to spare that aren't already on Tims CD.
> Whats the point?

The point is that maybe you are not the only person who runs with
drives that are so small. And while I agree with you that probably
most RT-11 or TSX-PLUS users do not use drives even as large
as 2 GBytes (I use a 600 MByte drive myself and find that is normally
more than enough capacity), there may be a few who could benefit
from even larger drives. The problem with the standard MSCP
DU(X).SYS device driver in RT-11 is that the software limits the user
to easily using drives that are smaller than 8 GBytes. While I know
that you are aware of the limitation, the actual question I asked is
if MSCP allows the hardware use of drives up to a 32 bit block
number? Again, I obviously did not make my question clear
enough since you did not answer it. Namely, if the DU(X).SYS
device driver in RT-11 could handle sending more than a 24 bit
block number to the hard disk drive via the use of SET commands
(which would allow a partition number with more than 8 bits), could
the hardware handle that?

I did not say that everyone would want to make use of that feature
if it were possible - I know that you will not and I will not. I was
just asking if it were possible and maybe someone might want
to do so?

I guess that the point I am trying to make is that I enjoy a software
challenge whereas you enjoy a hardware challenge. I look a
some hardware and see what is. You look at the same hardware
and see what could be. I guess that I do the same with software.
Then I also go ahead and try make it work. Many times, I actually
can enhance or fix software just as you make changes to the hardware.
Can we agree on that?

Sincerely yours,

Jerome Fine
Received on Sat Oct 14 2000 - 23:10:51 BST