Operating old Mainframes was RE: Collection policy

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Sun May 25 16:10:28 2003

> Well, understanding these computers in an architecture sense is one thing* -
> but operating and maintenance skills were usually verbally transmitted and
> rarely permanently documented. They can probably be redeveloped with


True, and even if they were documented, that's often not enough. You need
to have a 'feel' for the machine, or more exactly, you need to have done
it before.

> experience but this experience is likely to be at the cost of media damage.

One reason to always start with unimportant media...

Yes, I know that blank media for some drives -- particularly demountable
hard disks -- is difficult to find and expensive. But unless people do
continue learning how to run and maintain such drives, then knowledge and
skills will be lost for ever. To me, ensuring there's still one person in
the world who has aligned an RK05 from scratch was worth risking a disk
pack for...

>
> I would put this the other way round - people who had a good understanding
> of the old machines have some chance of getting a deep understanding of
> modern ones. In terms of the Instruction Set Architecture and programming

It makes no difference which way round you say it. If you _truely_
understand a modern machine, then you'll find the older ones pretty easy
to understand. Conversely, understanding an older machine will help you
understand modern ones.

> there are few difficulties in understanding one given the other (but for
> 'minor' things like self-modifying code and the concept of overlays). On the
> other hand, the lower level descriptions of the processor logic typically
> use terminology that is totally foreign to the modern logic designer - not
> to mention the implicit "wired-or" that is frequently used and not
> explicitly mentioned in the documentation or that with only a small number
> of logic gates per card techniques were used to minimise the number of gates
> that would never be seen on modern synchronous logic.

The less said about so-called designers who have problems with any of
that, the better!

-tony
Received on Sun May 25 2003 - 16:10:28 BST