ajp166 at bellatlantic.net
Wed Sep 6 19:49:24 CDT 2006
>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:
>> 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?
Yes, if you have the heath interface card as well. If memory serves
the standard RT-11 DX.sys was compatable.
>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
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.
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