BI & CI in Ultrix land

[George Robbins]

In article <1232 at atanasoff.cs.iastate.edu> heins at atanasoff.cs.iastate.edu.UUCP (Leeland Heins) writes:
> In article <7373 at cbmvax.UUCP> grr at cbmvax.UUCP (George Robbins) writes:
> >Well, as a capacity planning excercise, I'm looking at either a 6X00
> >or one of these newfangled 58XX systems and trying to come up with
> >a realistic configuration.
> >
> >A few questions:
> >
>    Only the first two ports on a DMF-32 have modem control.  We are using
> DMF32's with Hayes-clone modems on the first two ports, and they work fine.
> We are also using Emulex CS21/F, which is a DMF32 look alike (two DMF32's
> on one hex Unibus card).  The Emulex card has modem control on all 16 lines.
> Of course, you have to set the flags in your config file when you build your
> UNIX kernel to turn on modem control.

Yes, but trying to do the Ultrix flavor of dynamic dial-in/dial-out with
the hardwired carrier detect and talk to a smart modem with get you into
the painful catch-22 situations.  

> > and the DHU11 output speed
> >   is really limited to 9600 baud, with obvious consequences.
> 
>    Hmmm...  is the DHU11 really limited to only 9600bps?  TMF says it will
> do 19,200, but not 38,400.  I haven't used one so I can't say if that is
> really right or not.

The systems and options guide talks about what baud rates you can set it
to vs. the users manual: "the transmit firmware can supply a maximum of
1,000 characters/sec to any channel".  High-dollar electronic scrap in
my book.  The one I bought is still in the box, a used Able DH11 emulator
that cost me $500 is doing the job.

>    I don't know about CI tapes.  If you can hang a Unibus on the machine your
> cheapest route to tape drives may be 3rd party.

The problem here is the DEC as declared all the unibus peripherals to be
"unsupported" under Ultrix on the 6000 (and presumably 5800) series machines.

This doesn't really panic me, but I have real qualms about depending from
day one on something that DEC isn't going to support.  I'm currently running
odd disk drives on an object patched version of the hp driver and while I've
saved lots of money, I've pulled out some hair from time to time and if
turn over the system to somebody new, he'll be SOL when he goes to install
the Ultrix X.Y release.

-- 
George Robbins - now working for,	uucp: {uunet|pyramid|rutgers}!cbmvax!grr
but no way officially representing	arpa: cbmvax!grr at uunet.uu.net
Commodore, Engineering Department	fone: 215-431-9255 (only by moonlite)