Thanks. Hmmm. I guess you'd be right. I just may have to update those pages. :) tnx.! g.

The last time I looked tubes were analogue devices. One of their main uses is as amplifiers, which is definitely an analogue function. If I remember correctly, one of the main problems with early tube computers (1940s and 1950s), was actually getting the tubes to behave like digital devices. -- Dr. Mark Green mark(a)cs.ualberta.ca McCalla Professor (780) 492-4584 Department of Computing Science (780) 492-1071 (FAX) University of Alberta, Edmonton, Alberta, T6G 2H1, Canada

Depends. In the 1940s and 1950s they were used in both analogue and digital computers. After the early 1960s, tubes were replaced by transistors in digital computers (at least in North America), but they were still used in analogue computers. In terms of pure numbers, analogue computers greatly out numbered digital computers until some point in the 1960s. In the simulation area, digital computers didn't become cost effective for many applications until around 1970, particularly those requiring real-time. So, for early computers the use of tubes wasn't a good indication of whether the computer was analogue or digital. -- Dr. Mark Green mark(a)cs.ualberta.ca McCalla Professor (780) 492-4584 Department of Computing Science (780) 492-1071 (FAX) University of Alberta, Edmonton, Alberta, T6G 2H1, Canada

On Tue, 7 Nov 2000, Mark Green wrote: In addition, for real time simulation digital machines of that generation were wholly (too strong?) inadewuate to the task. In particular, I recall reading about a '60ish project by one of Britain's Formula One makers to use a computer to control a F1-machine driving around an actual circuit in lieu of the driver. As I recall the story, it did not make it beyond the second turn. However, an analogue computer handled the task quite well. Apocryphal? ??? - don Sounds like something Chapman might have done. Or BRM?

Anecdotal, how it is done is likely the critical factor, not the hardware it was implemented on.

"Mark Gregory" <gregorym(a)cadvision.com> wrote: Hi It still can be a hybrid even though parts were digital and parts were analog. Looking at the date of the machine, I would suspect that most of the calculating functions were analog and not digital. It may have had digital function for things like turning lights on and off but controlling pitch and yaw indicators was most likely an analog function. Looking at the pictures, I didn't see any tube portions that looked like digital functions. Some of the panels look vary much like the typical analog plug-in units used in other analog computers. I vary much doubt that the altimeter, rpm or compass were run from a digital source. I would say that to qualify as an analog computer, it should do most of the computation in an analog manner. I would suspect that this unit had most of its calculations in the analog world and just a few status conditions held in digital form. Then again, if I saw a digital looking computer someplace in the pictures, I might change my mind. I didn't see anything that looked digital, other than switches and lights. Dwight

Rick, I recommend the USPS. They cost a fraction of UPS and the others and I've had good luck with them. However the british postal service has a reputation for damaging packages so I'd try to have the item taken to a main post office or some place similar in order to minimize the time that the package is in their hands. But be carefull of the weight. I tried to ship a 60 pound package to Japan and found out that it was going to cost $280 because they would only ship it by priority mail. I broke it up into two packages that weighed 35 and 23 pounds and the shipping was only about $80. For japan, anything that weighs more than 40 pounds has to be shipped by priority mail. FWIW a friend of mine shipped a very expensive oscilloscope to Japan at the same time by UPS and they completely destroyed it! Then UPS tried to claim that it was improperly packed, had the wrong address and a bunch of other excuses. He finally had to have the regional manager come out and see his packing setup (all new heavy duty boxs, a $5,000 foam in place machine, etc) before they would pay the claim. Joe At 04:47 PM 11/7/00 -0800, you wrote:

At 03:11 PM 11/8/00 +0100, Hans wrote: The US Postal Servive. What used to be our offical post office. They're now a semi-private company. Joe

And much better for it, too. -- ----------------------------- personal page: http://www.armory.com/~spectre/ -- Cameron Kaiser, Point Loma Nazarene University * ckaiser(a)stockholm.ptloma.edu -- There's a sucker born every minute. -- P. T. Barnum ------------------------