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| Thread ID: 23188 | 2002-08-09 10:44:00 | A diversion... Analogue Computers | Terry Porritt (14) | Press F1 |
| Post ID | Timestamp | Content | User | ||
| 69766 | 2002-08-09 11:37:00 | Goddie, You'll keep as well!!! Can't be me actually, He looks as if he is wearing a Halo!! My Ex would say it should be Horns. Have saved the site to favourites to peruse tommorow. Lived in Eastbourne (the Pommie one) from 10yrs to 15yrs & never got to Hastings. One of the things on my list of things to do when I win Lotto. Wishful Poppa John :D | Poppa John (284) | ||
| 69767 | 2002-08-09 13:20:00 | Hi Poppa John. Is this the computer you were thinking of? Atanasoff - Berry 1937-1939, about 300 or so valves used. valve computer (www.ieee.org) Also, a while back you asked about the National Bank advertising music, The Four Seasons by Vivaldi. Did you know that the Warehouse have the CDs on sale for 89cents at present? They are in a cardboard cover. The number on the back of the cover is 3516.2038-2 I hope I got the above web address right, I usually seem to muck it up. Cheers. ExLL |
exLL (515) | ||
| 69768 | 2002-08-09 22:08:00 | That's really interesting exLL. It's really amazing just how many famous concepts were first drawn up on table knapkins :) Springing to mind is Mitchell, sketching out the Spitfire design on one, I think Barnes Wallis also used one to outline one of his designs, and also Niels Bohr with an atomic problem. The backs of envelopes must also have had special properties, as there used to be a saying about a problem being capable of working out on the back of an envelope. |
Terry Porritt (14) | ||
| 69769 | 2002-08-10 03:21:00 | There's a bit of argument about Athanasoff + Berry (did it ever calculate anything?) . There was a German who made a few digital computers in the late 30s and early 40s . The Nazis decided it wasn't useful, so he got no money . He used second-hand movie film as storage (punched holes) . He got up to a version 4, I think . The US Govt put a lot of money into digital computers (for ballistic table calculations) , but not one of them was finished before the end of the war . Maybe the Germans were right about the development time scale . A lot of the Bletchley "computing" was done with punched card equipment --- basically sorting --- with selection controlled by plug panels . People forget that after Hollerith and the US Census, card data processing was very highly developed . The early Enigma decoding was done with real mechanical computers (stacks of cardboard sheets with holes punched in each at appropriate places . Light shone through if there was a matchg . ) The Bombes were built from telephone exchange hardware --- relays and uniselectors . The various Collossi were valve computers, but very simple . I don't think they were really "programmable" except with plug panels . They had pretty hairy mechanical peripherals too: 1000 cps paper tape readers . They had some trouble with the paper tapes catching fire . |
Graham L (2) | ||
| 69770 | 2002-08-10 04:33:00 | And if you want to see an analogue computer, here is the Meccano Differential Analyser (www.cl.cam.ac.uk) from 1938, (and some other early computers). One of the 14 Meccano DAs built and used for artillery prediction tables in WW2 came to NZ in 1950. It is now at the MOTAT. | Graham L (2) | ||
| 69771 | 2002-08-10 04:56:00 | Don't know if you guys are into valves! www.netcomuk.co.uk Sorry,haven't found the fancy link thing. |
Neil McC (178) | ||
| 69772 | 2002-08-10 08:12:00 | The Otis King Pocket Calculator is a very powerful tool. Read about them here (dicklyon.home.mindspring.com) and here (chris.gillings.com). They even built one in to the handle of a walking cane at one stage. They can handle powers, roots, multiplication, division, logs and the rest of it. I really would like to get one for my self. |
-=JM=- (16) | ||
| 69773 | 2002-08-10 08:59:00 | exLL. No not that one either, the one I am thinking of was huge. It filled one or two rooms of the building it was in. It was 1938 tho, which for some reason was a very good year, when a fantastic boy baby was born. Cannot think of his name at the moment!!!!]:) Poppa john ]:) | Poppa John (284) | ||
| 69774 | 2002-08-10 09:26:00 | Thats more interesting info, JM, I would like to have one also, those in the pictures are really collectors items going back a bit. The other slide rule manufacturer that made very long length slide rules was Fowler. These were really big, mounted on a stand like a mortar. Cant remember the scale length, but probably about 6 feet or more, ie 2 metres, for the young lads. They could be read to about 6 figures or so depending on the position along the logarithmic scale. I have a small circular pocket one about 120mm dia. with a 50 inch scale length. (note the bilingual dimensional language) :) Refering to the differential analysers mentioned by Graham, as an aside, the simplest mechanical integrator is the 'Planimeter' used for measuring the area of a closed curve, and used to be found in most decent drawing offices. Another simple device for solving 2 dimensional field problems such as diffusion, electric field, heat flow and fluid flow was the use of conducting paper, or 'Teledeltos' paper, with the boundaries drawn in conducting siver ink. For 3 dimensional problems, electrolytic tanks were used, but they were cumbersome and not all that practical. A voltage was applied to the source boundary, zero volts to the sink boundary, intermediate potentials were analogous the pressure or temperature field acording to the problem. Similar problems could often be solved on paper using Southwells Relaxation method, if the boundaries could be defined reasonably. This was before digital computErs, began to be widely used for number crunching. Up until then, computOrs were generally rows of lowly, menial girls (not PC at all!) working away on their mechanical calculators, consuming vast quantities of analysis pads. |
Terry Porritt (14) | ||
| 69775 | 2002-08-10 09:58:00 | Hi Neil, I found that very interesting, especially the ball-bearing non-magnetic motor. It was weird. (and useless as a motor!) Re the *fancy link thing* you mentioned, godfather helped me with it a few days ago. Although the explanation is all there in the formatting options box and seems easy once you know how, I found it a bit hard to follow when I first tried to understand it. Here is my explanation of how to do it. (Purposely long winded for the benefit of any absolute newbies who may find it useful also): I will use these brackets { } so that I can demonstrate it without activating anything. When you try it, use these ones [ ] so that it will activate. When typing a reply, to see what options are available, click on *Formatting Options* at top left of the reply box. Another box will appear showing the various options. If you look at the bottom item you will see the details of how to enter web addresses etc. Basically it goes like this: Remember to use [ instead of { Firstly, type a left bracket like this { Then type URL= Then enter the web address Then close the web address with a right bracket} At this point you type in the name that you want to substitute for a web address, for example; VALVES You now close the instructions by typing {/URL} The whole line will now look like this: {URL=the web address will show here}VALVES{/URL} Note that there are no spaces before or after any of the brackets, but you can put spaces between the words in the name/s that you choose to use, eg: GLASS RADIO VALVES, instead of just: VALVES You can now click on Preview and it will show a clickable link named VALVES underlined in blue. If you have finished your message click on Post Message, if not, click on go back/edit to return to the message to make changes. |
exLL (515) | ||
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