One additional thought. The reason the so called "Y2K" issue started in the
first place was back when these systems were being created on line storage
was particularly expensive. A Gigabyte of storage cost multi-millions.
Therefore saving storage by only storing 2 bytes for a year vs. 4 bytes and
keeping packed numbers as small as possible was economically justified even
after the "Y2K bubble" costs were absorbed. Now you can get server class
300Gb disk units for about $500. Storage has become one of the cheapest
parts of the system rather than the most expensive.
Those who built those systems were not idiots nor were they short sighted,
they were driven by economics and the current status of hardware technology.
It's easy to wonder why the IMS databases were built the way they were and
consider the designer to have been less than adequate by today's standards,
but remember we are talking about a different eon in computer terms in the
latter part of the last century. The fact that some of these systems
survive today says volumes about how well they were designed in the first
place.
--
Jim Oberholtzer
Chief Technical Architect
Agile Technology Architects
-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Buck
Calabro
Sent: Thursday, April 23, 2015 8:48 AM
To: midrange-l@xxxxxxxxxxxx
Subject: Re: Y2K39
On 4/22/2015 11:22 PM, John Yeung wrote:
So, to address one of Dan's questions, about sliding the window, even
if IBM provided a system setting for this, it wouldn't make a
difference at some shops. Our Y2K problem had absolutely zero to do
with anything provided by IBM. It had everything to do with
shortsighted database design and application logic.
My one and only contribution to this thread is to remind people that what is
'short-sighted' in 2015 was deliberate and intelligent in 1975.
No one in their right mind would have asked a keypuncher to punch two
redundant digits (1 and 9) in front of every year. That is an actual,
measurable expense and an actual, measurable source of keypunch errors that
can be avoided altogether by using the 'natural' 2 digit year
representation.
Having established that there was an actual reason for recording only 2
digits, it is not much of of a meander down the cow path [1] to what we have
to deal with today:
We now have a
hodgepodge of date logic throughout our system.
At some point I realised that this is the natural state of software, and
that it's my job to accommodate change within that framework of old, very
old, really quite old, and someone who thought that nesting 22 IF statements
was a Good Idea. All I can say is that I am deeply thankful for service
programs.
--
--buck
[1] The Calf-Path by Sam Walter Foss
http://holyjoe.org/poetry/foss3.htm
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