WTB: Emulex MT-02 controller
ard at p850ug1.demon.co.uk
Fri Apr 25 16:18:59 CDT 2008
> Date: Thu, 24 Apr 2008 15:47:39 -0500
> From: Jules Richardson
> > Hmm, maybe the designers were sensible, and any critical timings are
> > solely on the device response side - i.e. the host can take as long as it
> > wants to process things, but the device must respond within a certain time
> > period (and then just happily sits there until the host acknowledges).
> QIC-02 is buffered via drive-local RAM, so it's not really fussy on
> the host-side timing. These tapes are streamers, however, so you
I was refering to critical timing between the hardware control lines. For
example I've used an interface (not QIC anything) where one device
asserted a signal, then the other device had to acknowldedge within a
certian (short) time (1us or so), otherwise there would be ig problems.
AFAIK on QIC02, one device asserts a signal, then waits of the other
device to acknowledge by asserting one of its signals, and so on. And
that wait can be as long as you like. Which means both sides can, IIRC,
be done in software/firmware with no problems
> Oh, Chuck has both QIC-36 and QIC-02 ISA inteface boards. He just
> wants the convenience of not dealing with buggy NetBSD drivers (the
> Linux QIC-02 drivers don't work at all anymore) and not having to
> look for spare DMA and IRQs for the boards. A QIC-02 host interface
> board is scarcely more complicated than an IDE interface. OTOH, a
> QIC-36 interface is usually a full-length board, packed with a data
> separator, CPU, RAM and other logic. From the CPU side, both appear
> as pretty much the same thing.
The QIC36 ISA card I have in my junk box appaers to be essentially a
QIC-02 host interfaxce and a QIC-02-to QIC36 bridge on the same PCB. I
keep it because the ASICs on the board are the same as those on a
separate QIC-02 to QIC36 bridge that I sometimes use with my PERQ, and
thus the ISA card is a source of spares...
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