Ted MacNEIL wrote:
Nothing beats the integrity, reliability, and security of mainframe.
(Of course, I'm biased)
Of course you're biased.. (and Ted I'm not directing this at you, but your comment is typical of
many I see).. We're all biased on this list (typically!!) but a lot of the time to me it seems to
be a head in the sand biased approach. Too many times I hear how wonderful the mainframe is; and
then when I take a closer look underneath the latest shiney Green/Blue/Gold stripe on the z door, I
find a hotch potch of applications and systems strung together over 30 or 40 years. The z10s are
probably one of the most hi-tech bits of kit you'll have in your machine room, and z/OS is pretty
good too ;-).. But what gives the mainframe such a bad name is usually the pile of 40 year apps
stuck together running on top of it and our resistance to change.. (oh, and our morbid fascination
with 3270!!) And why did we get this way?.. well it's what I call the pair of "IBM's double-edged
swords".
And I like to think I'm not writing this with a wilful ignorance of zSeries. I've spent 25+ years in
this game, 3 as an Assembler programmer, then the rest Sysproging in one form or another. And yes, I
know that makes me quite a junior compared to some of you old timers ;-), but having done most of it
as short term contracts I think I've seen the whole range from tiny single box sites right up to the
10+ footprints.
So what are these double edge swords? Well, firstly we have "Downward
Compatibility".
Yes, you're all sitting there thinking "That's a good thing, isn't it?".. "I can still run my zxy
program that I assembled way back in '72; how many other systems can I do that on?".
Well yes, of course it's a good thing, we all boast about it, "Hey, look how easy my upgrade is!".
But remember the other side of that sword! You see I feel that because we've never had to change
anything, when we do upgrades, we just keep running stuff forever. And not only do the apps stay
there forever, but as an industry I think it makes us very resistant to *change*. I mean, how many
times on this list do we keep harping on about how wonderful it was when we had to handcraft our own
IO routine etc etc!! We don't like change (and yes I'm talking to you writing notes on your stack of
puchcards!) And that resistance to change is partly what I think gives the mainframe a bad name.
And the other sword? Well, that is what I call "System Versatility". Basically, IBM's design that
allows any and every site to configure z/OS (and all its predecessors ) in any which way they want.
Yes, it gives great flexibility. Hey, what should I call my ISPF libraries? Today I'll be mostly
calling then SYS1.SISPblah blah or maybe ISP.SISPblah blah. or I could put version numbers in or..
etc etc. You see, I can do anything I want, and I guarantee it will be different from the shop down
the road, and all because IBM never came up with a *defined* way to it. In my opinion they still
haven't. Ok, the ServerPac defaults are a lot more structured than the old CBIPO, i,e. Sxxx for
target libs and Axxx for distribution libs, and the fact they finally dropped the use of version
numbers (what took you so long!). So why is this "system Versatility" such a problem? because it
makes it so damm difficult to maintain software, never mind the heartache it must cause vendors (I
can hear Gil's keyboard clicking away). And that difficulty just gives management the view that "its
always big and hard" to do anything. And here's the rub, IBM can't change it now
because...of...yep.. "Downward compatibility". And yes I know it's possible to design system
standards/configurations such that it *does* simplify upgrades/installation - but I very rarely see
examples being used - partly due to the history at the site, and also because I've never seen IBM
come up with a decent design on how to install and maintain z/OS. (And don't get me started on the
shamplexes we're forced to have in order to get cheaper sw costs!)
So we're stuck with it - we have this wonderful hi-tech flexible downward compatible system -
hanging like a millstone around our necks. So it's actually refreshing to read an article like this
- remember they never said anything about getting off mainframe, and also quite typical of the
response we saw on the list... Now where's that sand...
..and now we return to our scheduled broadcast
Cheers
Roy
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