[rescue] Personal progressions (was: what to do with a dec alpha 255)

Geoffrey S. Mendelson gsm at mendelson.com
Fri Jun 1 00:03:10 CDT 2007

On Thu, May 31, 2007 at 08:27:51PM -0400, Carl R. Friend wrote:
>     One needs to remember that most well-designed systems in the 1960s
> through the late 1970s were *well balanced*, not the "shove the
> bottleneck around" monstoriciries we get today; balance was what let
> an entire *system* function well as a cohesive whole, not just parts
> of it. 

That's the fault of DEC's sales force. During thew 1970's they got into
the "battle of the MIPs" (million instructions per second).

IBM based performance on a standard workload (a set of jobs they used 
to test the performance of a system) and rated the speed of succeeding
computers in realtion to a specific sustem. In the 360 line it was the
360/30 (original model) in the 370 it was the 370/158 (original model).

DEC created a CPU favoring benchmark, using the instructions that took
the least time to execute (and co-incidentaly did the least), and used
that to rate their computers in MIPS. They were constantly selling
their computers by the MIPS per dollar, and showing how they out performed
IBM computers by an order of magnitude.

It was all bogus, the DEC benchmark used instructions that incremented a
single bit in a register, while IBM used things like MVC (which could move
up to 256 characters in one instruction) and later MVC (which could move
up to 16 megabytes in one instruction, was interutable, and would fill
the destination with a chosen character if it was longer than the 

This in the end killed DEC as the 80386 and later chips out MIPSed
anything they could produce. Again it was not a fair comparison, but
they had trained their audience to ignore fairness.


Geoffrey S. Mendelson, Jerusalem, Israel gsm at mendelson.com  N3OWJ/4X1GM
IL Voice: (07)-7424-1667 U.S. Voice: 1-215-821-1838 
Visit my 'blog at http://geoffstechno.livejournal.com/

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