27 Dec
2008
27 Dec
'08
7:49 p.m.
On Dec 27, 2008, at 7:19 PM, Steven M Jones <classiccmp at crash.com>
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.
I understand it's possible to upgrade the
backplane to 22 bits --
how is this done?
I have a VT103 (with cards), and a funky rackmount cage with three
separate Qbus backplanes in it (thanks Phil!) that may only be 18 bit.
A while back I grabbed a number of bare Q22 backplanes off of eBay
in case I found I needed to replace the backplanes on these systems.
Haven't gotten around to even assessing feasibility, but the plan is
to try and just swap the backplanes whole. I've got a handful of
KDJ11-A dual-height CPUs to use if that works, though I'll probably
need some MXV11's or something to go with them.
The bigger question, to my mind, is how to cheaply attach disks.
With the VT103 I believe some folks have placed small disks (3.5"?)
under the CRT, where the TU58 drives would have been on a
PDT-11/130. But you still need a drive interface to talk to 'em.
Perhaps one of the Micropolis half-height ESDI drives would fit, and
work with your controller.
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...
Josh
--S.