Craziest ebay price EVER

Roger Holmes roger.holmes at microspot.co.uk
Fri Oct 27 12:34:40 CDT 2006


On 27 Oct, 2006, at 07:41, ard at p850ug1.demon.co.uk (Tony Duell) wrote:

> It's not that hard to trace out schematics of a classic computer [1],

Not all classic computers are micros. Fancy tracing the schematic for
my 500 square foot second generation mainframe? Fortunately I
have most of them, along with the 'address book' which lists every
logic signal, its sources (think wire-OR) and destinations. Its on
roughly A3 paper and is in two volumes four inches thick.

Welcome to the new chap.

BCD is not just a bit coding, its a card code as well. It lacks things
like parentheses and brackets but has things like 1/4, 1/2 and 3/4.
My 1301 uses it, though strangely there is not a one to one mapping
from characters from the card reader to characters on the line
printer! The old Friden Flexowriters used a similar code too, though
they seem to have varied too. The old Elliott 920 code was different
from the code used by my own Flexowriter (which could punch and
read 8 paper tape, or using the same mechanism, along the edge of
a punched card size medium which I think could be fan-folded. I
guess this allowed the operator to write on the rest of the card).

Roger Holmes

(Who has at home what might be a collection of the largest
computers in private ownership - unless you know different
as Esther Rantzen used to say on "That's Life").





More information about the cctech mailing list