From: pfjw@aol.com   
      
   On Thursday, January 31, 2013 4:27:43 PM UTC-5, sam_mo...@gomail.com wrote:   
   > I want to build a computer entirely out of tubes, and be able to   
   >    
   > download and store the entire internet on it.  How many tubes do I need?   
      
   Eniac, the first "practical" digital computer used only tubes as 'switches'.   
   Something on the order of 17,468 vacuum tubes, 7,200 crystal diodes, 1,500   
   relays, 70,000 resistors, 10,000 capacitors and around 5 million hand-soldered   
   joints went into the    
   machine. Parts of it still exist at Penn. Its memory was the functional   
   equivalent of about 2300 bits (1.3KB), although there is no actual functional   
   comparison of Core Memory to Flip-Flop memory. It could store (up to) ten (10)   
   signed (+/-) ten-digit    
   numbers, full stop.     
      
   It had less computing and/or memory capacity than the Commodore VIC 20. Which   
   had five (5) KB of ram, of which 1.5KB was system memory. Power consumption   
   for the ENIAC was about 160KW/H.    
      
   Extrapolating Wildly: If the internet memory capacity is 58 petabytes (each   
   petabyte being 1,000 terabytes) the memory capacity requirement would be quite   
   large - but TUBES did not store the actual data, only processed it. So, you   
   would have to consider    
   the number of tubes to make a reasonable processing time, and the number of   
   tubes, capacitors and flip-flop devices (analog relays) to store the data.   
   Then the power to run it all.    
      
   Comes to 10 to the 15KB. 10 to the 42 bytes.    
      
   Raw numbers only, and definitely comparing apples (flip-flop) to oranges   
   (core), and all approximations:   
      
   Keeping in mind that a typical memory chip has something over (the equivalent   
   of) 40,000,000 discrete components on it, with CPU chips having much, much   
   more, the number of vacuum tubes will be in the several billions. But, for   
   practical purposes, if    
   only one billion tubes are used ENIAC style, that would require, with   
   supporting infrastructure, about 10 MW/H of power, about the equivalent of the   
   entire output of two (2) standard nuclear plants.    
      
   2,830,000,000,000 hand-soldered joints (again, assuming ENIAC-style). Assume   
   10,000 assemblers making 180 joints per hour. That math will be astounding.   
   Not to mention floor-space required, cooling considerations, access, and so on   
   and so forth.   
      
   So, the short answer:   
      
   More tubes than have been produced world-wide since 1910.   
   Something far over 2 square miles of footprint. ENIAC was only 1,800 s.f., but   
   remember, access, heat and memory issues using relays.    
      
   Interesting exercise in silliness.   
      
   Peter Wieck   
   Melrose Park, PA (and Penn grad).    
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)