Subject: Re: Oooooh... IDE to Q-bus/Unibus adapters.
To: emanuel stiebler <>
From: Michael Kukat <>
List: port-vax
Date: 07/07/1999 21:43:54
Hi !

> > If you look at the modern UltraDMA-drives, IDE definitely IS much faster,
> > and even cheaper,
> Sorry. But that's absolutely NOT true. Anyway not if you talk about using
> them not only for a benchmark, but in a computer, running an operating
> system. Any many of them ...

I'm talking of the most used comparison of old SCSI-II standard and modern
UltraDMA-IDE. I know the benefits of SCSI, and i only have SCSI boxes standing
around here. It makes fun to copy big data amounts between 2 harddisks with
4 MB/s... and this only was on my old AHA-2940 with an old Seagate hawk (yes,
i copied FROM this, it just died...) to a Quantum somewhat UltraWide adapted
to 8-Bit SCSI. IDE is always 16bit, so you can't do a real comparison between
both, and practical use of a good implemented SCSI support does make the daily
usage faster... It was only a benchmark comparison in this case.

> > But is an IDE drive on the QBus really the right thing for these boxes ?
> Ok,
> > it's cheap, but it's not the right style :-)
> Doesn't have anything to do with style ;-))
> Most vaxen are bigger than the specification of 18" wire for IDE ;-))

SCSI also tells something about cable lenghts. But i have around 10 feet of
cable from the last harddisk inside to the CD writer outside of my box...
IDE/ATAPI even doesn't have a correct termination here, so nobody might
expect secure data transfer with a cable longer than from mainboard to hard
disk bay in a standard PC enclosure.
It's just not made for failsafe industrial use.

> > If you want to do it real good,
> > just adapt a 386 mainboard including onboard-IDE to the QBus, then you
> might be
> > able to write the MSCP stuff on this "controller"
> The MSCP protocol is not the problem, it's really the cable-length. So you
> have to make something like a Drive-Card, which is a controller with the
> harddisk on board. (want to buy one ;-))

I had a filecard for my 8088 some time ago... If you use a notebook harddrive,
you could bolt it to a QBus card :-)

> > ... TQK50 also uses an 186 CPU.
> because they had o box full of it ? ;-))

Ok, they found no other use of them. Otherwise, they would have been keyboard
controllers :-)

so long.. Michael