15 Jan
2010
15 Jan
'10
1:54 a.m.
Dave McGuire wrote:
On Jan 14,
2010, at 9:57 AM, Jerome H. Fine wrote:
SCSI hard disk drives are relatively rare, but
probably inexpensive.
The older drives of less than 10 GB are no longer seen very often.
However, I have a number of (very?) noisy 2 GB drives I rarely use.
The host adapters are still expensive. The alternatives are ESDI or
MFM drives. ESDI controllers may be less available. The RQDXn
controllers from DEC should be more available.
Good heavens. On what planet are SCSI drives rare? And on what
planet are they inexpensive? At first (after picking myself up off the floor) I
thought maybe you
mistyped and meant "SCSI host adapters", which certainly are
rare...but since they're far from inexpensive, that couldn't be it.
I apologize!! I was VERY wrong about the SCSI hard drives.
To inject a little reality into this paragraph:
SCSI drives are everywhere, while ESDI drives are comparatively
difficult to find, and MFM drives are becoming somewhat difficult to
find. For DEC machines, SCSI host adapters are rare and expensive,
ESDI controllers are a bit more common and less expensive. RQDX3s
are as common as dirt, with RQDX2 and RQDX1 boards less so but still
not difficult to get.
YES!!
Since the RQDX3 is a dual board and now easy to find from
so many VAX and PDP-11 systems, that would be the better
solution. Avoid the RD53 drive if you want to be able to read
the files after the drive is turned off. The other RD5n drives
seem to behave if they can be written in the first place. But
formatting an RD5n drive is not trivial and requires XXDP
software on a PDP-11 system.
For myself, I still have a few ESDI hard drives. Most are
Maxstor and Hitachi of 600 MB, 5 1/4" FULL height
and heavy. I also have a few ESDI controllers. All ESDI
hardware was purchased between 15 and 20 years ago
when I needed reliable hard drives of around 600 MB.
I suspect that for a company (not a hobby user) willing
to pay the cost, a Qbus SCSI host adapter can easily be found.
I can let you know a general range, but I suspect that $ 1000
might not be too much for some of these boards at quantity one.
DEC, CMD, Emulex and Dialog all made Qbus SCSI host adapters.
I don't know who sold the most Qbus SCSI host adapter boards.
Sincerely yours,
Jerome Fine