21 Jun
2009
21 Jun
'09
2:49 p.m.
Tony Duell wrote:
Sure, but most HP machines have HPIB :-). The HP120
doesn't properly
support the HPIB port in the BIOS (IIRC there's no BIOS function to read
from an HPIB device) so you pretty much have to talk to the 9914
directly. Not a big problem, but if you get it into the wrong state you
may find you can no longer talk to the disk drives.
Yes, that's true.
For talking to instruments, I prefer to use an
HP9000/200 machine with a
second HPIB port (HP98624). Firstly there's much better standard software
support for the HPIB interface, and secondly, if one of the instruments
'hangs the bus' (likely in my case as I might well be repairing said
instrument), I can still talk to the disks.
Second ports are always nice.
And then there's the attributesm which are set on
a character line basis.
Basically, every character is either normal or enhanced (decided by bit 7
of the chracter code). You can only have one type of enhancement in a
given line. So you could have normal and underlined characters in the
same line, but you can't have normal, inverse, and underlined characters
all in the same line.
Okay, I'll grant you that was a bit weird. Honestly, though, it was
never an issue for me, or the original owner.
Another problem is that AFAIK there's no official
way for a CP/M program
to set the parameters of the serial ports (not even the 'printer' port).
The serial chips are on the terminal processor bus, there's no direct way
for the application processor to talk to them. There's an undocumented
way to run code on the terminal processor (in that at least one HP
application does that), but I can't find out how to do it.
I don't know how 'official' it was, but I had PORTSET.COM which directly
set up the serial port from the CP/M side. Er, it RAN on the CP/M side,
and set up the ports.
I'd much rather have an HP9000/200....
An attorney's office near me had the HP-125. When they upgraded, I got
their old system for a song. Nobody I knew was getting rid of an
HP9000/200. This was before eBay, and I really didn't have a good way
to find specific equipment. One takes what's available. Still and all,
I very much enjoyed using it, and it was the first machine I had that
would be a reasonable terminal, HPIB controller, AND general purpose
computer. Also, they were SLEEK. So, scoff if you want, but I liked it
just fine. It probably would have been more difficult than average to
repair hardware problems on it, but in about 15 years, I never had one.
Warren