> > > You already gave me that incentive about three times, and both of those
> > > ideas were FAR easier. Well, building a replica of Zuse's Z-3 may not be
> > > easier. But my Apple ][ programming ideas are easier, and bringing my
> > > Marchant is MUCH easier. So why should I bother doing the difficult stuff,
> > > if the reward is the same? :)
> > A Z3 replik ? Only functional (al relays, but modern part) or
> > an exact copy ? As for the functional replica it's just some
> > work and an awfull lot of money for the parts (my guess, some
> > 8000 USD), but easyer than most _exact_ emulations of complex
> How did you arrive at the sum of $8000? I thought there were 600 relays in
> the Z3. I didn't realize relays were so expensive. I was also thinking
> that it might be possible to use other parts (for example, telephone parts
> like ferreed switches or a small crossbar module). That might require
> changing the design.
Depends on the parts you gan get for low/free. But forget about
the dream of using old telephone parts, especialy relays - this
time is gone for mor than 20 years - there are no more old scraped
exchanges to get 600 relays (and even if, they would be most likely
EWS type machines, their relais aren't just single orphans, but
rather high integratet mechanical structures, where it is almost
impossible to extract a single relay). You have to buy new ones
(or beeing lucky to find enough high quality pcs. at a surplus
store). And you cant go for the 4 Mark types with one switch, since
the Z3 uses often more than one. Also it's a must to use socketed
types, for easy exchange (that would also simplyfy the design) -
an exception to this might be if you want to build it as small
as possible - but the relays needed in this case might cost even
more. At a number of some 600 relays and sockets I assume an
average price of an relay at DM 10 plus DM 4 per socket. That
gives 14 Mark (or USD 8) per installed relay - assume you use an
Euro card style (within a 19" rack) you might end up with 4 or
maybe 6 relays per card (4 if you use 90 degree socket to reduce
card height - or if you want to use a low density to keep it
easy to wire - or 6 if you go for the maximum - a 4 relay per
card design will result in about half the heigh per card as a
6 relay per card design, so the whole computer will be 25%
smaler). This means you need some 150 PCB boards at, lets say
10 Mark each - with an aprobiate connector for 10 Mark each.
To mopunt them, another connector is needed in the rack at 14
Mark each, eding up with 34 Mark per board (or 90 Mark including
the relays). Now we have 13500 Mark (or ~8000 USD) and thats
only the PCBs, relays, sockets and connectors - I assume the
rack(s), card mountng, power supply(s) and small parts (like
diodes, resistors and wireing) are just for free.
Of course you can go and collect relays wherever you find them
and end up with hundreds of different types and dozends of
needed voltage levels etc. not to mention that this beast
will need _a lot_ more room (usinge the design describen
above we need at _least_ one full height rack, but maybe
two) and dont forget the problem of different kinds of
mounting for the relays.
Gruss
H.
> It's possible. Bear in mind that I've never done any electronics work
> before. I mostly have a vague idea in my head. (A few Nixie tubes, a
> desktop-sized box, some keys.)
Step aside, and wait for a real stunning idea, soon to arive
(no comment).
--
Ich denke, also bin ich, also gut
HRK
Received on Wed Jan 27 1999 - 06:39:31 GMT