14 Feb
2015
14 Feb
'15
12:26 a.m.
On 2/14/2015 1:14 AM, ben wrote:
On 2/14/2015 1:05 AM, Dave G4UGM wrote:
I think that needs real machine work. Strange what you could do 100
years ago you can not do today.
Computer controlled stuff is good for may things but not that.
error: many things
-----Original Message-----
From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Dale H.
Cook
Sent: 14 February 2015 03:41
To: cctalk at classiccmp.org
Subject: Re: building my own relay computer
At 08:14 PM 2/13/2015, Ben wrote:
The alu has never relay been a problem with relays, but what about main
storage? Punched tape (paper/film/card) is no longer with us for I/O.
Punched tape is about. Check out the "green keys" list, 5-level stuff
comes
up from time to time, generally at low cost. There is some ex-CNC
items on
E-Bay at present but for silly prices. Whilst I haven't seen any on E-Bay
there were three Documation readers advertised on the Vintage Computer
forums.
Fifty years ago I got around that by building my
own card reader (very
slow)
for input and hand-punching Hollerith cards with
a hole punch. That was
some years before I got access to an IBM card punch in high school.
Output
was a set of electro-mechanical counters, and they were a real pain to
implement.
Many folks have implemented photo electric tape readers, but these
tend to
be clocked off the small feed holes. I guess it wouldn't be too hard to
build a photo electric reader that has a 3-d printed feed wheel that was
driven by a stepper motor. In fact I am pretty sure you could even use a
coil and ratchet arrangement, like this one here:-
http://grabcad.com/library/cam-operated-ratchet-pawl-1
but operated buy a coil and magnet rather than a rotating cam. Some
one has
actually made a complete but operated mechanical punch card computer..
http://observationdeck.io9.com/a-3-d-printed-hand-cranked-punch-card-compute
r-1481921919
so I don't think its hard. Getting things 3-D printed isn't hard, in fact
most FabLabs will have one and things can be printed for the cost of
materials. Also Hack Space...
I think it's the punch that's harder. You would need to harden the
punch
pins, and the would need to have a very exact fit. I guess a CNC router
could be used to make these...
Ben.