> Date: Tue, 1 Jun 1999 09:15:24 0 > From: Mike Millen <[EMAIL PROTECTED]> > Subject: Re: OS. CLI, and "gooey" > In a nutshell, digital computers tend to be programmable, i.e. they > can be loaded with software to do almost anything. > Analogue (English english :) computers are only programmable via patch > cords and switches, and even then tend to be designed for a specific > task only. Precisely. The Target Intercept Computer (TIC) on the F-4 was rebuilt every time the range of its missiles was improved. That was the only drawback ( lack of easy programmability ) and we eventually converted to a digital version because major improvements were coming about every 6 months. The Digital TIC was not without problems, though; unlike the earlier analog version, it couldn't *simultaneously* evaluate the 45 or so dynamically- changing resolver outputs and gyro offsets. It would bog down while tracking a close, manuevering target - and the lag in computation just kept growing until angle-tracking of the target via the radar antenna was no longer possible; it would break lockon at an angle-tracking rate that was about one-third of previous performance. > To sum up: whoever told you that analogue computers were impossible, in > some ways couldn't have been more wrong; to equal the capabilities of > an analogue computer the digital machine would be impossibly huge. Quite so. While our digital replacement had to fit within the same area as the earlier computer, there was a loss of certain capabilites when the switch was made. Of course, other capabilities were added, too. When a larger 30mm gun pod capability was added to the ballistics of the existing internal 20mm gun, the software change took about 30 seconds, accomplished by plugging in a handheld loader directly into the aircraft. Modifying the old type required hours of soldering and electrical alignment, with the computer removed from the jet. Another post will address the idea of the analog neural net computer ( which was part of the lead-in to this now very divergent thread ) - and a separate subject from the resolver/synchro/op amp analog computer we speak of here. - John T. -- Arachne V1.5a;alpha, NON-COMMERCIAL copy, http://home.arachne.cz/ To unsubscribe from SURVPC send a message to [EMAIL PROTECTED] with unsubscribe SURVPC in the body of the message. Also, trim this footer from any quoted replies.
