>Megan wrote:
> Or you could try ESDI... I have a couple of machines with the
> Andromeda ESDC controller and hitachi DK515-78 drives. They
> work just fine with MSCP device drivers...
Jerome Fine replies:
I have used both the Hitachi DK515-78 and the DK516-15 drives
with an RQD11-EC ESDI controller from Sigma. I must be missing
something. The larger DK516-15 drive (1.2 GBytes) is very slow -
about a third of the speed of the DK515-78. I suspect that I need
to interleave the sectors, but I have not been able to find a setting
to do that with the RQD11-EC.
In addition, I am normally able to compare one RT-11 partition on
one DK515-78 drive against a different but identical RT-11 partition
on a second DK515-78 drive in about 4 minutes and 11 seconds.
For those who don't know, an RT-11 partition is 32 MBytes.
I use BINCOM in that case and the CPU is a PDP-11/83 in a
BA123 box. However, when I have more than 7 quad boards
in the backplane, the compare time increases to about 10 minutes.
I suspect that the problem is that my system is on the very edge
of some hardware condition which causes everything to slow down,
the same problem perhaps as with the DK-516-15 drives. Can
anyone suggest what could be causing the difficulties? The system
is about the same when I use a PDP-11/73 and normal memory
except that I don't seem to remember having a problem when
there were more than 7 quad boards and I used the DK-515-78
drives. But the DK516-15 drives are always very slow.
Sincerely yours,
Jerome Fine
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Received on Thu Mar 06 2003 - 08:18:00 GMT