Jerome H. Fine wrote:
Josh Dersch
wrote:
I have a number of external TRS-80 external hard-disk enclosures,
which at one point contained MFM-style drives -- since the cabling
is the same as ESDI I was considering putting an ESDI drive in one
and cabling it to the Emulex controller, thus allowing an external
drive and cutting down on space/power issues in the VT103.
An external hard disk enclosure is not essential. I usually just use
a PC
power supply and a bare hard drive with the cables from the controller
hanging out the back of the VT103, especially when using an ESDI hard
drive which requires more power than an MFM hard drive. I suggest
that you also place a fan beside any ESDI hard drive since they usually
run very hot.
No, not essential, but I have very few working, RQDX3-compatible,
half-height MFM drives left. And even those are very low capacity. I
have a number of high-capacity ("high" being a relative term -- anywhere
from 80 to 760mb) ESDI drives, but most of them are
full-height. I
don't mind having an external box, though it would be very cool
to have
an all-in-one unit.
Note that an RQDX3 (dual board from DEC WITHOUT a boot ROM)
is probably quite reasonable with an M8190 and Qbus memory as far as
power is concerned. An RQDX1/2 (quad board from DEC WITHOUT
a boot ROM) needs 6 amps for the 5 volts and will often overload the
VT103 power supply when the other boards are added to the total needed
to run a minimum system.
I have a number of RQDX3's, but I'll probably go
with the Emulex QD21
ESDI controller that I have. It has an auto-boot option, which will be
useful since the 11/23 board I have just has the ODT ROMs...
As for placing the hard drive under the CRT, while there is ample room
for
a 3.5" hard drive, I have managed with an ST412 5.25" hard drive -
although
I agree that it was a VERY tight squeeze. A third party MFM controller
(with a boot ROM), M8186 / M8192, memory and DLV11-J are sufficient to
run
RT-11 and the VT103 power supply is sufficient to support the ST412 as
well.
In
addition I see two projects out there for Qbus disk interfaces:
wintersweet:
http://www.mscpscsi.com/
CHD's Q22-ATA:
http://www.chd.dyndns.org/qbus_ide/
No further information, like availability or compatibility, and no
timeline for when I'll drag out the stuff I have and start
contributing ... ;^)
Man, One (or two!) of those things would be sweet! I lucked out and
snagged a CQD-220 SCSI controller off eBay for $80 last year, but I
doubt I'll ever find another SCSI controller for that price...
Was that a CQD 220TM? A CQD 220T will handle only a tape drive. If you
have a CQD 220TM that works, $80 is certainly a very low cost. It
usually
supports optical disk drives as well and may support CDROM drives. In
my case, I have an Adaptec AHA 2940AU SCSI host adapter on my PC
and can use a Sony SMO S-501 media to move 295 MB from the real
PDP-11 to the PC running E11 under Windows 98SE. I am hoping that
E11 will also be able to use the optical drive under Windows XP, but I
will not know for about 6 months.
Yeah, it's the 220TM. I have it in my
MicroVAX II at the moment. It
works with CD-ROM drives but does not like booting from them (it doesn't
seem to be patient enough to wait for the drive to spin up and come
ready). I currently am using a pair of SCSI Jaz drives for both
removable and "permanent" storage -- I can "dd" the contents of a
bootable CD-ROM to the Jaz disk and then boot from the Jaz disk on the
VAX. I've installed a couple of versions of NetBSD, VMS, and Ultrix
this way (though the Jaz drives interact poorly with Ultrix because they
spin down the disks after a few minutes of inactivity, which Ultrix
appears to be unable to cope with.) It's nice to have bootable OSes on
removable media to make fooling around with different operating systems
fairly painless. Though I really don't like Jaz drives/disks that much...
Sincerely yours,
Jerome Fine
Thanks for the info!
Josh