Adrian: Fair point on the possible military-uses. I think that's an aspect we often forget about today, compared to back then and "height of the cold war" era. The world was "smaller" then (1950s/1960s) in terms of population being easier to control. Bear with me: what I mean is, it seems then government was far more concerned about technologies and ideas getting into foreign hands. I don't run a business and don't know anything about foreign trade - but "from the outside" it just seems back then, there was a lot more scrutiny on such things in comparison to today. Computers (or "data processing systems" in general) were definitely a competitive advantage that you wouldn't want your adversaries to have.
A few years ago I got a FLIR camera, and on the back it says "export controlled" It's the only consumer-device I ever got that has an explicit Export Controlled sticker on it. I imagine if I were to bring it with me on a trip to China, that probably wouldn't go well. Combined also there was a bit more honor in representing your product (back then). Meaning, if you called a little box of wires a computer, first people would claim false advertisement, and second government agents would be interested to know what you're up to (I didn't live in the 50s, so I suspect some of that is a bit hyperbole - but my point is that in contrast today, false-advertisement is kind of the norm and it takes quite a lot for a good ol'e FBI raid these days). (and to clarify - there are some good ads and good products out there, what I mean is there doesn't seem to be much in consequences to false-advertisement, and you can't just bad-mouth that company with the bad-product because they can quickly just morph into another name -- like those cheap $50 "amazing" drones that they claim can do everything a $1000 Mavic Pro can do, mmmhmmmm.... or that CyberTruck is starting to look a bit suspect on the claims it had, but who knows, a little firmware update might solve it all) Actually I haven't checked - do the authors of that book happen to still be around? I'm on the road today, will have to look more into that later tonight. On Sun, Jul 21, 2024 at 7:08 AM Adrian Godwin via cctalk < cctalk@classiccmp.org> wrote: > I think when the book was written, digital computers were the latest tech > and analog computers had been actually pretty common for 30 years. > Technology included fluid ( > https://www.sciencemuseum.org.uk/objects-and-stories/how-does-economy-work > ), > mechanical (https://en.wikipedia.org/wiki/Kerrison_Predictor) and > electronic. > > I don't think the title was related to the analytical engine, my take would > be that it was just an encouragement to the reader that it was an > achievable and usable device. > > It may be that the military uses contributed to the lack of public > documentation of the mechanical systems. > > > On Sun, Jul 21, 2024 at 9:03 AM Dave Wade G4UGM via cctalk < > cctalk@classiccmp.org> wrote: > > > > > > -----Original Message----- > > > From: Tony Duell via cctalk <cctalk@classiccmp.org> > > > Sent: Sunday, July 21, 2024 5:42 AM > > > To: General Discussion: On-Topic and Off-Topic Posts < > > cctalk@classiccmp.org> > > > Cc: Steve Lewis <lewiss...@gmail.com>; Tony Duell > > > <ard.p850...@gmail.com> > > > Subject: [cctalk] Re: the 1968 how to build a working digital computer > > > > > > On Sun, Jul 21, 2024 at 3:08 AM Steve Lewis via cctalk < > > cctalk@classiccmp.org> > > > wrote: > > > > > > > What I meant was that in the title of the book they use "digital > > computer" > > > > and I wonder if there was ever a book describing a mechanical "analog > > > > computer" - and what they might even look like. > > > > > > There have been mechanical analogue computers and I have at least one > > book > > > describing them on my shelves. > > > > > > Typically they used disc integrators with an igenious arrangement of > > strings and > > > drums as a torque amplifier. These were then coupled by gearing which > > had to > > > be set up for each problem (simple gear trains correspond to fixed gain > > > amplifiers, differential gear trains to differential amplfiiers, etc). > > > > > > I doubt you could make one from cardboard, but there was at least one > UK > > > University that made a simple one from Meccano (similar to Erector Sets > > across > > > the Pond?). It was on show, not operating, in the London Science Museum > > at > > > one time, but I think it's in storage now, > > > > Several people have made Analog Computers from Meccano. The "first" I > > think was at Manchester University in the UK intended as a prototype or > > proof of concept it was later replaced by an engineered device. > > Both were on display in the Science Museum but I believe they are now in > > Storage. Cambridge University UK also had a Meccano Analog Computer. I > > believe this is the one now on display at MOTAT, Aukland, New Zealand > > > > https://motat.nz/ > > > > there are some pictures of it on my one drive (if it asks you to sign in > > and you don't wish to use an incognito window) > > > > https://1drv.ms/f/s!Ag4BJfE5B3onlsxny71p3CPOQV4svA?e=aSdamK > > > > in more recent times Tim Robinson built one... > > > > https://www.meccano.us/differential_analyzers/robinson_da/index.html > > > > .. so there are some clues on how to do it about, but no book as far as I > > know > > > > > > > > -tony > > > > Dave > > G4UGM > > > > >
