[HECnet] NT 4 on AlphaServer es40

[Steve Davidson]

-----Original Message-----
From: owner-hecnet at Update.UU.SE 
[mailto:owner-hecnet at Update.UU.SE] On Behalf Of Johnny Billquist
Sent: Tuesday, February 12, 2013 15:48
To: hecnet at Update.UU.SE
Cc: lee.gleason at comcast.net
Subject: Re: [HECnet] NT 4 on AlphaServer es40

On 2013-02-12 17:18, lee.gleason at comcast.net wrote:


Speaking of IAS, it really looks cool when reading specs, 
but I've 
never   >touched it, and another aspect of those specs is 
that it looks 
like it   >would be rather slow...


    I managed an IAS system on an 11/70 back in the day. I 
don't have 
any formal benchmarks, but it didn't "feel" any slower than 
equivalent 
RSX11M and M+ systems I have been on.

Cool. The reason I mentioned it because of just such things 
as you mention below - device drivers being full blown tasks 
do imply quite a lot more overhead.

    IAS was a real treat. If you wanted them, you could 
SYSGEN in real 
timesharing features for supporting users who didn't 
require realtime 
response to their needs. It included lots of concepts   that 
later made 
their way into VMS, (although, considering this crowd, I 
don't know if 
that will be considered a plus here...).

Well, I for one don't mind VMS, even if I think RSX is way 
cooler most of the time.

    The most interesting feature for me was the way device drivers 
worked. Called "handlers", they were complete tasks, instead of the 
APR and a couple registers' worth of context provided by 
RSX11M/M+ drivers.
You could do a lot more work in them, a lot easier than on 
the other 
RSX variants. The down side is that any driver action involved 
scheduling a task rather than the lightweight context 
switch required by a driver.
But, having said that, the system I managed supported lots 
and lots of 
terminals at 9600 baud, and wasn't bogged down by servicing 
interrupts, so scheduling a task to do IO didn't turn out as bad as 
you'd think it would.

Yeah. After having done a lot of device drivers and stuff in 
-11M+, I sometimes long for the freedom of a task context. 
That's when you go diving into ACPs, but it would be nicer if 
the driver was a task in itself.

    I managed RSTS sytstems as well and I vastly preferred 
the richer 
environment provide by IAS. I recall being at the DECUS Symposium 
where the future of IAS was announced (that is, no 
future...). There 
was much lamentation, gnashing of teeth and rending of 
garments over that.
Support did actually continue for quite a few years after 
that though 
- turns out that the US Air Force was a   big IAS user, and 
DEC didn't 
want to upset the government.

    BTW, I'm always looking for IAS related "stuff" - copies of the 
DeVIAS newsletter, IAS software (espcially DECnet-IAS) and the like.

I believe IAS never went to Mentec, but actually stayed with 
DEC, for the very same reason (although I also heard that 
supposedly it was IRS, but urban legends are probably abundant).

IAS-11 never went to Mentec.   Too many government accounts (both US and
others).

-Steve


Never seen TRAX in real life either, btw. What was so 
good about it?

    Me neither, though I did use some of the VT61 and VT62 terminals 
that were developed for it - like VT-52s, but with IBM style block 
mode. Not a lot of software outside of TRAX used their block mode 
features, so they were pretty rare.

The VT61... The VT62 was a different beast, and I had one for 
many years... It's basically a VT52 with inverse video attribute.

	Johnny

-- 
Johnny Billquist                                   || "I'm on a bus
                                                                    ||   on a psychedelic trip
email: bqt at softjar.se                         ||   Reading murder books
pdp is alive!                                         ||   tryin' to stay hip" - B. Idol