brightside S9 wrote:

I don't know where you got the story about the engineer taking a long
time and nobody allowed into the computer room, but yes some IBM
equipment was upgradeable at a cost to the customer that just involved
moving a jumper or loading new firmware. It was never a secret. In
other IBM equipment a low cost (to the customer) upgrade meant
changing a large percentage of the internal electronics.

You should understand that IBM didn't sell equipment it sold, and
still sells, solutions to business prioblems.

I know cos' I was there. You'll have to work out where there was for
yourselves.


Here is an account from an IBM engineer of the 1960 and 1970s:

As a new concept and to make manufacturing efficient, the bigger CPUs in
the 360 range were assembled with all the drivers and memory they could
ever need. Only the bits the customer paid for were active, the others
were disabled. Some were hard wired. Some were "software", but of a
special kind, either capacitive or inductive. The capacitors were
strips of mylar about 2" x 15" that had a printed circuit 'ladder' with
square holes between the rungs. The routine was created by punching
holes in either a rung or an upright, to make the current in the ladder
go past or round the holes. Then the mylar strips were placed on to a
metal strip with square pegs of cobalt steel that matched the square
holes on the mylar and clamped together. To change the spec, engineers
would replace some of the mylar strips. I can't remember what the
inductive ones were like. These devices were actually the boot routine
for the CPU so that's how the spec for the machine was changed
The bit about the computer room being locked whilst this was in progress
is pure myth. Computer rooms were far too busy and changing a routine
would take all night. I have done it!

Bill

In message , David
writes


wrote in message
...
On Nov 15, 12:31 pm, "David" wrote:
Hi
Another thought and a question, assuming I got it right in my mind
now, by
the way thanks to those who replied and helpful.

Here in UK we can buy Freeview SD boxes, cheap as chips you might
say, and
also Freeview HD box at a lot higher cost and off putting I would
think to
the normal Joe Public.

What, £20?!

http://www.ebay.co.uk/itm/270835712548


Refurbished!
Already sold 647, and over 10 to sell, could be a high number.
Must be a lot of Tesco customers returning these in the first place,
after paying a lot higher price.

I nearly got one of these a couple of weeks ago (£30 in a Tesco store).
Wife raised eyebrows, so didn't. However, couldn't resist this offer, so
treated myself. It's a really nice box, and has latest software fix
installed. Nice menus etc, and has manual tune option. SD pictures are
good, but don't know how good the real HD is, as I haven't got an HDMI
lead yet. Well satisfied for £20.
--
Ian