Summary One of your readers...My memory

[David Farber <dave () farber net>]

Begin forwarded message:

From: Gene Spafford <spaf () cerias purdue edu>
Date: September 4, 2008 1:31:51 AM EDT
To: dave () farber net
Cc: "ip" <ip () v2 listbox com>
Subject: Re: [IP] Re:   One of your readers...My memory

So, to summarize what I got:

There were several one-off fully transistorized computers built by  
various groups in the mid-1950s.

The first commercial system that was offered for general sale that was  
completely transistors was the 608, announced by IBM in April of  
1955.  It had 3000 transistors.  In current dollars it was possible to  
buy a base model for a modest $700,000.

The price for transistors used by IBM in their machines circa 1958 was  
approximately $2 each (or $20 current), as cited in Thomas Watson's  
autobiography, Father, Son, & Co., on page 296 (thanks P. Capek and DV  
Henkel-Wallace).

I wanted to verify a calculation I had used in a magazine article (to  
come out in October) that in 50 years of semiconductor computing,  
we've seen almost a nine order of magnitude drop in per-transistor  
cost in current dollars (although we've also seen an increase in  
transistors per system use, by a factor of about 6 orders), and about  
7 orders of magnitude drop in per-byte cost in secondary memory (about  
$.10 per byte of drum in 1958).  Of course, other costs, including  
main memory have also dropped in a similar fashion. Total system cost  
has dropped by a factor of about 500, but capabilities have grown  
tremendously as well (I don't have a measure of that, but in the  
millions of times faster, I believe).

This all goes to points I've been making in invited lectures over the  
last year, but I wanted to reverify my numbers for the print article.  
(And I am going to let the magazine have priority on the essay, so I  
won't expand further until October...unless I end up speaking at your  
institution. :-)


My thanks to everyone who responded.  It was fascinating, and I  
greatly appreciate your willingness to respond!

--spaf




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