russian PDP-11 like K1801BM2 CPU Startup reading w/o address?

I was using 'linear' in its mathemtical sense. A linear sysnmte is one such that if input A gives oputput B, then input kA (k a constant multiplier) gives output kB (same k). And if input C gives outptu D, then input A+C must give output B+D. It is clear form this that any aplifier iwth any form of AGC is not linear. If we increase the input signal (multiply it by a suffiicenlty large 'k'), the gain drops, so the output is less that you might expect. Oh dear, oh dear... We need to think back to the early 1930s. The problem was to produce an adjustable audio oscilaltor. LC oscillators were impractical because the L and C needed were large, and it's difficult to make a 1uF variable capacitor (say). And the indcutoir is likle to be iron-cored, which is likely to be non-linear. The normal way it was done at the time was to have 2 RF oscillators (such thigns couple be made adjustable fairly easily) -- one fied, the other variable. The outputs were mixed and the differnvee frequency extrcted. That was the audio output. One big problem was that if the 2 oscilators were at similar frequencies (to get a low freqeuncy otuput), they had a habit ot interfering with each other. THis either led to them jumping into lcok (so the output frequency became 0), or at least producing a very distorted differnce signal. The solution was to make an RC oscilaltor. Large adjustable resisotrs are perfectly possible, and can be used in such a cirucit with fixed capacitors. Fred Terman was a professor of electrical engineerign at Stanford (IIRC). He had a research student working on this, and said student made an RC oscilaltor using a Wein bridge network as the frequency-dependant part, the gai nwas stailbied by having a small filamanet bulb as one of the gian-control resistors in the amplifier. It worked well, in fact it backame a commercial product. The name of this student was William Hewlett. The product was the model 200A audio oscillator. -tony