6 Sep
2006
6 Sep
'06
5:49 p.m.
Subject: Re: Heathkit H27
From: "Ethan Dicks" <ethan.dicks at gmail.com>
Date: Thu, 07 Sep 2006 12:30:11 +1200
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>
On 9/7/06, Jay West <jwest at classiccmp.org> wrote:
Yes, if you have the heath interface card as well. If memory serves
the standard RT-11 DX.sys was compatable.
Can the H27 (dual 8" floppy drive) be hooked
up to an H8? Or was that
strictly an H11-only device?
Dunno about the H8.
> Of for that matter, can an H27 be hooked up to a non-heath Micro PDP11?
My recollection of debugging some H27 issues a couple of years back is
that there's a boot prom on the Qbus card for the H27. If that's the
case, then as long as it isn't stomping on a bootstrap ROM somewhere
else on the bus, then you should have no problems. Heath's card should
be register-level compatible with either the RXV11 or the RXV21 (can't
remember which one right now).
The prom on card can be disabled. It worked well with 11/2 and KDF-11A
cpus.
The card is RXV-11 compatable. The big upside with the H27 is it would
format 8" (RX01) disks. The downside is the drives, the spindle clamp
was plastic and would dryout and crack.
My H-11 came with a KDF-11, DEC memory, pretty much DEC
everything; just the Heath backplane and PSU and floppy controller.
The previous owner never booted from floppy, though; he hacked the
case and added an off-to-the-side CD-interconnect and used an RLV11.
Thats a ugly hack. Many were upgraded to 11/23 cpu, Q18 ram and some
times DLV11j for more IO with fewer boards.
It took a bit of work to get it all back together.
I'll bet. Test the PS well, the LVSMPS was not every reliable.
Allison