VP/ix serial terminals

[Bill Kennedy]

I am running AT&T 386 UNIX with Simul-Task 386 (aka VP/ix) in a
no name clone with a CompuTone AT-4 smart serial card.  All in
all I am pleased enough with VP/ix (that's easier to type than
Simul-Task!) and I am very impressed with how they were able
to graft PC oriented things onto a moderately stupid terminal.
I have even figured out how to make it work with a Televideo,
a Qume, and a Zenith

I have some anomalies that I can not explain for myself.  If I
try to run DOS from a terminal on the smart serial card I get a
pregnant pause, a message

Cannot enable DOS mode for this device

a much longer pause and then my UNIX prompt back.  I can log in with
my luggable in cu (onto a modem on COM1) and it works fine.  If I try
to run DOS from a directly connected terminal on COM2 I get a very
prompt message

Error attempting to open serial device
Press Enter to continue

and then everything is OK.  I don't get that message when logged in on
a modem or when I'm on the console (I suppose that's obvious).  Perhaps
the brain trust can enlighten me.

I'm curious as to why it won't work on any smart card port.  That's
probably a function of the driver and something the driver must do when
VP/ix wants to open it.  I hope not because I'm getting ready to replace
the COM2 driver with one that takes advantage of the NS16550A UART and
CTS/RTS handshaking.  Can anyone explain what a serial driver must do
in addition to work with VP/ix?

I'm equally curious as to why I get an open error on the COM2 device
but it recovers and proceeds normally.  Finally, is there a repository
of VP/ix terminal files anywhere?  I'd like to contribute a couple and
collect a couple more.  They are a pain in the neck to write and test,
surely we can exchange them like we do termcap/terminfo's.

Whoops!  I said "finally", I lied.  Does anyone know why VP/ix must
dongle both floppies (A & B) before it will start?  Mine are in an
outboard enclosure and are normally powered down.  It takes just that
much longer for VP/ix to start up if there's nothing there.  I might
add that VP/ix does a creditable job of shimming DOS to fit a serial
terminal.  I tried three things I was certain would not work, DAC Easy
Accounting (ancient uSoft BASIC), the venerable szap from Software
Toolworks, and MKS vi.  They are all very screen memory oriented and
szap is very function key oriented.  They all worked!  They even ran
OK on the DOS partition on drive 0.  I was impressed.  Thanks for any
thoughts, wisdom, steers.
-- 
Bill Kennedy  usenet      {killer,att,rutgers,sun!daver,uunet!bigtex}!ssbn!bill
              internet    bill at ssbn.WLK.COM