WTB: Emulex MT-02 controller

[Chuck Guzis]

Date: Fri, 25 Apr 2008 22:18:59 +0100 (BST)
From: (Tony Duell)

> 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.

The best known example of this in spades is the Pertec tape 
interface.  "Here's the data, catch it!" type of interface.  On read, 
there's a strobe asserted when data's ready, but no handshake or 
other means of throttling the flow.  Same for the write side--a "data 
accepted" sort of signal, but the data must have been presented on 
the host side.  Lost data conditions aren't diagnosed, unless the 
host decides to incorporate logic to do it (i.e. detect strobe before 
data accepted/ready).  Given that there's no standard on tape block 
length, most Pertec controllers have a bunch of RAM or at least a 
good-sized FIFO to deal with the condition that the host may not be 
able to keep up with events.  Data errors are detected by the drive, 
but presented during the course of a transfer, so again, the 
controller must be there to latch them when they occur.

IIRC, QIC-02 uses handshaking; QIC-36 does not.

> 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...

The QIC-36 ISA cards I have are Wangteks--they use an 8085 and a fair 
number of house-labeled ICs to do their dirty work.  They're 
integrated units, though I suspect there's a fair amount of shared 
logic with the Wangtek QIC-36-to-02 controller, as it also uses an 
8085 and has some of the same house-labeled packages on it.

My QIC-02 cards are by Alliance Technology; nothing to write home 
about--just some LSTTL logic and maybe a PAL for address decoding.  
About what you'd expect--and apparently clones of the Wangtek PC-02.

Cheers,
Chuck