Does anyone have an H11 and need a H27 card? -spam

Richard Cini rich.cini at
Mon Dec 28 19:52:44 CST 2020

I have an H11 but not an H27 controller. The story I remember reading is that it ran a modified and incompatible RT11 because DEC didn’t want to cannibalize sales on the inexpensive PDP-11’s. I have a write up about this on my web site.

I can say that it does indeed run real RT11 if loaded with a TU58 emulator or if using SCSI (like with an Emulex card and SCSI2SD). A second SLU is needed for the TU58 of course. I ran a DLV11J on mine.

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From: cctalk <cctalk-bounces at> on behalf of Bill Gunshannon via cctalk <cctalk at>
Sent: Monday, December 28, 2020 8:18:04 PM
To: cctalk at <cctalk at>
Subject: Re: Does anyone have an H11 and need a H27 card? -spam

On 12/28/20 7:07 PM, ben via cctalk wrote:
> On 12/28/2020 4:43 PM, Bill Gunshannon via cctalk wrote:
>> On 12/28/20 6:37 PM, ben via cctalk wrote:
>>> On 12/28/2020 4:23 PM, Kevin Lee via cctalk wrote:
>>>> Remember.
>>>> Wherever you go......
>>>> There you are .......
>>> What about the Invisible Man?
>>> Ben.
>> All joking aside, I sure wish I had a complete H-11.  I have
>> PDP-11's but the H-11 was unique.
>> You know, it would be even cooler sitting next to an H-8.
>> Too bad so few seem to have survived.
>> bill
> I suspect it was more the case of too few were purchased. The high price
> of the H-11 must have been a factor. Was the H-11 cpu crippled for Heath
> Kit? I wished for one at the time, but was there any application software?
> Ben.

As far as I knew it was a real DEC CPU Module.  I expect any application
that ran on RT-11 on the LSI-11/02 would have run on the H-11 but then,
you couldn't just walk into your local computer hobby shop and by RT-11
software.  :-)


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