[time-nuts] tube GPS receivers

Bob Camp lists at rtty.us
Sun Jun 23 22:37:57 UTC 2013


Hi

Switching diodes came along much earlier than transistors. A lot of "tube" logic was actually diode / resistor / tube logic. To fit my (likely bent) definition of "pure tube" you would have to *not* use solid state switching diodes. 

Bob

On Jun 23, 2013, at 6:06 PM, Kenton A. Hoover <kenton at nemersonhoover.org> wrote:

> Weren't the original TRANSIT computer (AN/UYK-1) proofed out in vacuum tubes before they were able to build it with transistors?
> 
> --  
> Kenton A. Hoover
> kenton at nemersonhoover.org
> +1.415.830.5843
> 
> 
> On Sunday 23 June 2013 at 14:50, Paul Berger wrote:
> 
>> Hi:
>> 
>> The SAGE computers, which I had the pleasure of seeing the last two  
>> operating, had an all vacuum tube array of core that consisted of 33  
>> planes of 64 x64 cores for about 16K worth of memory. These where all  
>> vacuum tube computers. IBM offered a 4K all vacuum tube core storage  
>> unit for the 701 and 702, the same unit was built into the 704 and the  
>> 705 had a larger core storage with 35 planes of 50 x 80 cores. The  
>> Remington Rand Corp. and the RAND Corp. also shipped computers that used  
>> core for main storage in the mid 50s which likely used vacuum tube  
>> drivers. At that time there where apparently no transistors available  
>> that could supply the drive current required for core memory.
>> 
>> On 6/23/13 5:29 PM, Bob Camp wrote:
>>> Hi
>>> 
>>> I've both used and worked on core memory machines. They ones I have seen all used solid state devices in the core memory sections of the machine. I've never heard of a pure tube machine with more than "register sized" core.
>>> 
>>> Bob
>>> 
>>> On Jun 23, 2013, at 1:47 PM, Chris Albertson <albertson.chris at gmail.com (mailto:albertson.chris at gmail.com)> wrote:
>>> 
>>>> Magnetic cores were not invented until the 1950's and realy cam into use as
>>>> tubes were beibg replaced by SS. But there isnot reason yu can't build a
>>>> tube computer with core memory. I have actually seen and used a computer
>>>> that had one megabyte of core memory. The stuff was still in use in the
>>>> late 1970s 1MB was a lot of RAM in 1975.
>>>> 
>>>> You can have very good reliability with tube circuits. It was just that
>>>> few people wanted to pay for it. Down time was cheaper. It is not hard to
>>>> add redundancy to a circuit but it does have a huge cost multiplier effect.
>>>> 4x or 5x the price. One simple way is to use 3 or 4 tubes with their
>>>> output tied to a resistive adder. If one tube fails the result (because it
>>>> is binary) is still the same. With computers no one would pay for fault
>>>> tolerant design until it was reasonably affordable. Even today we mainly
>>>> just put up with failure except for airplane controllers, huge web sites
>>>> like Amazon and the like.
>>>> 
>>>> 
>>>> On Sun, Jun 23, 2013 at 9:53 AM, Brian Alsop <alsopb at nc.rr.com (mailto:alsopb at nc.rr.com)> wrote:
>>>> 
>>>>> On 6/23/2013 14:40, Bob Camp wrote:
>>>>> 
>>>>>> Hi
>>>>>> 
>>>>>> AC137 doesn't ring any bells. True tube core (no solid state at all)
>>>>>> isn't something that was dimensioned in K words. A couple hundred words was
>>>>>> pretty big stuff. "Quite a bit" of core done that way is a lot of tubes. As
>>>>>> the number of tubes goes up, the time to failure comes down….. hours …
>>>>>> minutes … who knows.
>>>>>> 
>>>>>> Bob
>>>>> Yeah, it gets to be like the cross country aircraft races in the 20's. The
>>>>> mechanic had to fly with the pilot. (The MTBF of many of the engines used
>>>>> was measured in hours.) If necessary he had to climb out on the cowling
>>>>> while in flight to change plugs and fix whatever possible without landing.
>>>>> What would OSHA say about that?
>>>>> 
>>>>> Needless to say future generations will probably find lots of aircraft
>>>>> spark plug artifacts in their digs.
>>>>> 
>>>>> Brian/K3KO
>>>>> 
>>>>> 
>>>>> 
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>>>> 
>>>> 
>>>> 
>>>> --  
>>>> 
>>>> Chris Albertson
>>>> Redondo Beach, California
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