On Sun, May 17, 2026 at 7:46 PM Robert Armstrong via cctalk <
[email protected]> wrote:

>   I have a Rainbow 100A with the Univation hard disk.  Works (wow!), but
> the
> Univation HDD controller was not DEC compatible and you have to boot from a
> floppy to get the disk drivers loaded.   And of course, the 100A ROMs
> didn't
> support any kind of hard disk, DEC or otherwise.
>

Correct.


>   Did anybody ever make an updated ROM image for the 100A that supported
> booting from the Univation directly?   I think the 100A used 2716 EPROMs,
> and it'd be easy enough to burn some new ones.
>

Not that I ever heard of. But I didn't sail too close to the 3rd party
marketplace.

The Univation HDD controller connects through SASI to its hard disks (which
were sold with a SASI to MFM adapter board). I disassembled the driver in
the
hopes of using the Univation card I bought on ebay, but I wasn't able to get
my card working: the system always hung for me, even when messing with
the jumpers (I have a Rainbow 100B from back in the day I take out and
play. with from time to time). I had hoped to add Univation sport to Venix,
but I gave up on that in part due to the booting issue. Univation also has a
different on disk partition table than the DEC controller used.

https://github.com/bsdimp/rainbow100.git has my efforts, in
3rdparty/univation.
./rainbow100/3rdparty/univation/src/univdrv.S has fully comments source. I
think
I use the gnu assembler, not masm, there. It's been a while and I've not
checked
tonight. It's too late, but I had to reply.

Warner


>
>
>   And is there any surviving  documentation for the Univation?  Bitsavers
> seems to have nothing.
>
>
>
>   Thanks!
>
>

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