[Nottingham] OT - developing skills on the mainframe

[BUNTER MATTHEW]

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11.23


>> > Mainframes are good in applications where little CPU is required bu=
t
>> > great raw I/O bandwidth, a modern example is serving static webpage=
s for
>> > a hosting company.
>> >
>> > Rob
>>
>> Hmmm, I'd disagree with you there, I'd say mainframes are good with
>> large chunks of non interactive data... they don't handle small chunk=
s
>> very well, i.e network packets, key strokes, that kinda thing.. I may=
 be
>> wrong, but that's what the two mainframe geeks on the ibm stand at th=
e
>> linux show told me... and they seem to know there s**t. So if you got
>> lots of batch processing to do (like a bank for example) there the
>> business..... hmmm, they use em in banks, maybe worth learning aftera=
ll
>> for a 100% pay rise... :-))))

>And you think web pages with forms and serving static content isn't old=
 style
>'block mode' processing...

>Rob

I didn't want to get into 'Mainframe evangelist mode' but it might help =
Lee's
'Make it cool' problem as well as addressing other questions.

What are mainframes *NOT* good at :
Calculations such as finite element anaysis, thermodynamics, crash testi=
ng,
rendering, fluid mechanics. High 'internal' CPU use calculations.

What are mainframes good at:
High I/O, 'heavy' (calculate interest on 10,000 bank accounts, inventori=
es,
lots of developers, users at the same time* etc.) loads that need to use=
 data
from various sources. The reason the mainframe is so good at I/O is that=
 the
CPUs don't do any I/O work - there is an I/O subsystem.

As for the mainframe adapting, becoming more modern. What do you want? J=
ava -
its on, C++ - its on, Websphere Application Server - recommended to be o=
n the
mainframe instead of Unix when dealing with mainframe based dbs, encrypt=
ion -
its there, security - ever heard of a mainframe getting hacked, me neith=
er.
Linux on the mainframe is even more interesting : network in a box anyon=
e?
Firewalls, DNS, email, a DMZ all running with hipersockets - internal ne=
twork
speed equivalent to memory speed, Development environment sure give me f=
ive
minutes, need to apply a patch - let me clone the prod machine and test =
it
first, we are testing clustering on the mainframe for CAD applications a=
t the
moment, how much cooler does this need to get?

Downsides:
No graphics. Because its a system that started in the 60s it is BIG. It =
does
take several years to learn to be a systems programmer. The benefits of =
such a
long history - it is clever, it fixes itself, 99% of the things the main=
frame
can already do are targets for people like SUN, HP, even Microsoft (who =
have
hired the co-founder of Amdahl - they were hardware suppliers) in terms =
of
availability/uptime.

Upsides:
Mainframe skills lead to on average a 20% premium over non-mainframe com=
petent
applicants (The Future os System/390 www.dcta.com). Mainframes are every=
where
and growing, IBM has seen demand for S/390 MIPS escalate by more than 60=
% per
quarter since mid-98. 95% of Fortune 1000 companies are using OS/390 and=
 DB2
on their central server. I only took the decision recently to try and ge=
t very
technical on the mainframe. I reckon if I work for another 25 years then=
 I can
my skills will be in demand.

*Just as an aside, our mainframe is 600MIPS, has six LPARs (logical part=
itions
- basically six machines in one), 3 Tera of data, does nearly 2 million
transactions per day. We do email for 12,000 mailboxes, have connections=
 to
all over Europe, US and South East Asia at the moment - there are just o=
ver
5,000 people connected to one of our production LPARs now. We have a web=
server
on one LPAR, LDAP on another, the security database is used to verify al=
l
dealers around the world when processing spare parts.

Sorry about the length of this mail, hope it helps to persuade people ab=
out
the viability of the mainframe.

Regards,

Matt

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