TD Systems TDL-11 QBUS (SCSI?) card

Sean Caron scaron at
Sun May 3 11:08:06 CDT 2015

How neat! I have seen an old, uh, Dilog card, around as well, I think it
is, that isn't very well documented; it's got a 50-pin header on it like
SCSI but is commonly listed for sale at a cost less than that of a known
SCSI card... I had always assumed it was maybe a SASI card or something a
little unusual, maybe a tape controller ... I was kind of suspecting the
same for your board, especially given the date of 1984 on your board, that
is fairly early for SCSI, prior to the ANSI standard, right?

That this one turned out to be SCSI with the strange Z8400 CPU plus 2x
INS8255 PIO gives me just slightly more confidence on the whole, to maybe
try out some of these "proto-SCSI" looking cards.

So ... not a bad thing to come across in a load of old Q-bus cards!



On Sun, May 3, 2015 at 3:00 AM, Glen Slick <glen.slick at> wrote:

> On Sat, May 2, 2015 at 10:41 PM, Seth Morabito <lists at> wrote:
> >
> > A great idea, and yes I do. I've made dumps of the ROM (an Intel 2764)
> > here:
> >
> >
> >
> > The ROM is simply labelled "IAX 3.2". I ran `strings` on it and it
> > confirms there is some kind of utility intended for SCSI, and there
> > appears to be RL01 and RL02 support, so maybe it's more like the
> > TDL-12 than I thought it was!
> >
> From a very quick look at the TDL-11 firmware dump I can see some
> similarities to the TDL-12 firmware. In particular I can see some
> binary data that would be DMA'd into the PDP-11 host memory that would
> be executed as the host side communication channel to the TDL-11 on
> board configuration utility.
> I would have to spend more time disassembling the firmware to try to
> figure out what triggers it to DMA that code into the PDP-11 host
> memory and then start the execution of the configuration utility.

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