Re: big, fast, etc, was is Vax addressing sane today

John Levine <johnl@taugh.com> writes:

That's fine for workloads that work that way.
>
Airline reservation systems historically ran on mainframes because when they were invented
that's all there was (original SABRE ran on two 7090s) and they are business critical so
they need to be very reliable.
>
About 30 years ago some guys at MIT realized that route and fare search, which are some of
the most demanding things that CRS do, are easy to parallelize and don't have to be
particularly reliable -- if your search system crashes and restarts and reruns the search
and the result is a couple of seconds late, that's OK. So they started ITA software which
used racks of PC servers running parallel applications written in Lisp (they were from
MIT) and blew away the competition.
>
However, that's just the search part. Actually booking the seats and selling tickets stays
on a mainframe or an Oracle system because double booking or giving away free tickets would
be really bad.
>
There's also a rule of thumb about databases that says one system of performance 100 is
much better than 100 systems of performance 1 because those 100 systems will spend all
their time contending for database locks.

after leaving IBM was brought into largest airline res system to look
ten impossible things they can't do. Got started with "ROUTES" (about
25% of the mainframe workload), they gave me a full softcopy of OAG (all
scheduled commercial flt segments in the world) ... couple weeks later
came back with ROUTES that implemented their impossible things.
Mainframe had tech trade-offs from the 60s and started from scratch
could make totally different tech trade-offs, initially ran 100 times
faster, then implementing the impossible stuff and still ran ten times
faster (than their mainframe systems). Showed that ten rs6000/990 could
handle workload for every flt and every airline in the world.

Part of the issue was that they extensively massaged the data on a
mainframe MVS/IMS system and then in sunday night, rebuilt the mainframe
"TPF" (limited datamanagement services) system from the MVS/IMS
system. That was all eliminated.

Fare search was harder because it started being "tuned" by some real
time factors.

Could move all to RS/6000 - HA/CMP. Then some very non-technical issues
kicked-in (like large staff involved in the data massaging).  trivia: I
had done a bunch of slight of hand for HA/CMP RDBMS distributed lock
manager scaleup for 128-processor clusters.


--
virtualization experience starting Jan1968, online at home since Mar1970