Is there a good book for learning about valves/tubes?

/Everything/ was weird back then :)

Except, in the case of the 803 etc, Tony Hoare's Algol-60 compiler which was groundbreaking.

It was still was weird in the 1970s microprocessors. Consider the RCA1802, the Motorola 14500, and what was that one without an external address bus?

At least Intel 4004 and 4040. 3 power supplies and weird clocking.

I agree on Hoare's Algol. It was a huge step forward from Autocode and direct octal code input.

--

-TV

The GE Transistor and Tunnel Diode and SCR manuals were great too. I still have them.

Those are normal, if primitive.

The 14500 processor was a 1-bit machine.

The one without an external address bus was the Fairchild F8. Its PC was contained in each of the support chips; must have been fun fun fun if one got out of sync with the others!

The 1802 wasn't too odd, except that the PC was designated by a 4-bit register under programmer control.

I did both, trimphantly reinventing a simple FSM in the latter case :)

The Algol compiler fitted in 4Kwords. I met Hoare once, and he was surprised when I mentioned having used it :)

On Thursday, 13 August 2020 at 13:59:08 UTC-7, Tom Gardner wrote: ...

The first computer I used was an Elliott 803, at Bangor University, with 8k words (it had a second cabinet for the additional 4k). We ran Algol with i t which was loaded from paper tape, a 6" diameter roll. The run time librar y was on a second slightly smaller roll of tape and had to be loaded with t he executable from the compiler.

That machine had a 39-bit word, and used a serial architecture running at ~

145kHz clock rate, with OC45 transistors giving about 0.003 Mips IIRC.

kw

A very fair question.

As a young lad I had no contact with valves. At uni I had no need to know anything about them and studiously (is that even possible?) avoided them. Now at home much more because of CV19, I have lots of spare time and while it is not going to be a source of any income I would like to fill at least some of my ignorance.

So I am looking for a good general introductory book on the subject. I see lots of recommendations which I will go through 'till I find something of the right level.

Alternatively with all this free time I could go out more, but everywhere I am supposed to stand has a big black 'X' on it, and I've seen too many Road Runner shows to fall for that!

probably some nice warm audio amp I could claim superior to harsh 'digital' ones and flog them off for a fortune

I used one while was in the 6th form, in the neighbouring Ewell Tech (now NESCOT).

I'm not sure whether they loaded Algol from the paper tape, since it also had the (sprocketed) magnetic film devices.

The instruction cycle time was 276us.

I almost went to Bangor, but Southampton was more convenient.

If you are ever near TNMoC, go and see one working, and listen to it playing music (the high notes are very flat!). When I mentioned I was an electronic engineers and had used one, they whipped out the schematics and we discussed them.

Now that's what I call a /good/ museum. By comparison, Bletchley Park next door is a bog-standard museum only worth seeing once.

Audiofools have a reputation for buying Tek scopes and stripping them of their valves.

===========================================================

** Which is still going unanswered.

** And you imagine reading a book will do that ?

** What subject is that ?

We cannot reads your mind.

** So you are not going to answer the Q at all ?

Wot a PIA you are.

..... Phil

----------------

** Not audiophools as such - but cunning opportunists out to exploit their addiction. Much like illegal drug dealers really....

.... Phil

Even you can't be expected to know everything. Sadly some of the most in teresting and useful tubes came too late to have a long, useful life. Digit al TV killed off most or all of the remaining Tube transmitters, leaving th at job to racks full of drawers of semiconductor trays connected to complex dividers and combiners. The only advantage is the CPU can power down and d isconnect a damaged tray, while terminating the pair of unused ports. Harri s was early into modular solid state transmitters. Their 5KW AM wasn't much more than a bunch of paralleled, modular SMPS, and filters. It did elimina te the need for a modulation transformer, but the bad new is that some stat ions transmit subsonics below 10Hz with them. The rumble from the speakers masks the desired audio.

The basic cycle was 288 us, and most instructions used two cycles,

576 us. IIRC, the only single-cycle instructions were control transfers.

There were two instructions in a 39 bit word, 6 instruction code bits and 13 address bits for 19 bits per instruction. The extra bit in the instruction word was an address modifier bit: If it was on, the address of the second part was indexed with the result of the first part before use.

--

-TV

Ach, the 276 was a typo on my part; I remember it being a 2kIPS machine, i.e. 576us. I don't think I was aware of the 288us timing.

ISTR I used the instruction modifier bit in my hand-assembled program. That converted from one 5 channel paper tape code we had at my school to the Elliott 5 channel code. (ASCII was wonderful :) )

I forget the details, but it had two "states" (for fig/num shift) and a computed goto based on the next character read. Someone else tried to do it with if-the-elses, and failed miserably.

Although I didn't realise it at the time, that taught me that /thinking/ and working out the right abstraction makes things much more tractable.

Youngsters don't seem to realise that, and just use whatever they've been taught.

I was going to comment that the audio speed of the 803 meant that listening to it run on the speaker was a useful diagnostic tool. If the burble changed tone or stopped, something had happened! This was on the one in the maths department of WCAT (which became UWIST) in Cardiff.

Agreed about TNMoC too. Not sure I saw their 803, but did discuss a device they have which used Dekatrons, since I used them for counting in a student project I made in the early 1960s. I donated some valves and my late Dad's valve tester, since they ran a valve exchange scheme. I also contributed a display board showing the antecedent companies to my then employer International Computers Limited. Deeply boring!

Mike.

Somewhere I have a cassette tape I made as a schoolkid. "Fetch Algol" sounded lie a broody hen.

The WITCH is the oldest operating computer in the world.

The 803 is in the same room as the ICL290x, next door to the WITCH.

Simply because dekatrons are fun, I recently bought a dekatron counter without the associated geiger tube. The knob on the front panel sets the tube voltage to 200-350V(?), and that is accessible to fingers on the front panel connector. Touch that, and it counts at 50Hz.

It is moderately entertaining to have someone watching as you measure the voltage before touching it.

The 5-bit + case code was picked from the Telex teleprinter network, but for some reason Elliott decided to use differenc character codes.

One of the early programming challenges was to make a tape that would have letters and figures correct even when read backwards.

I agree on ASCII.

--

-TV

The audio of the 803 came from the most significant bit of the instruction regiater. The high-pitched whine of a dynamic stop was the 288us cycle of a jump to self.

--

-TV

I thought letter-shift and figure-shift had been consigned to the dustbin of history - and good riddance.

Now youngsters use it all the time, with another shift thrown in for good^h^h^h^h bad measure :(