Mainframes vs PCs (was Re: discrete transistors) - test-drb@ccmp.vtda.org

19 Oct 1998

According to the November '95 Popular Science, p88:
The Apollo 11 guidance computer had 2K of RAM and 36K of ROM, and
barreled along at 1 MHz. The circuits consisted of 24 modules
contained in two trays, weighed 70 pounds, and required 70 W of power.
To issue commands, the astronauts used a unique interface that
consisted of a number pad and an LED readout. Commands were issued
in "noun-verb" format; the astronauts would key in numbers that were
codes for commands like "display velocity" or "change program".
  Nasa computers on the ground were somewhat more powerful, but not
much, according to Merritt Jones, a space physicist for the Gemini
and Apollo programs who now works for IBM. " The machine used in the
mission control center, which was the most powerful commercial machine
at the time, could execute 1 million instructions per second," he 
recalls. "It cost $4 million
and took up most of the room. It had one megabyte of memory."
next comes a description of modern computers and how laptops can do
'90 Million Instructions per second  and is small enough...'
...
 things into and out of memory rather than bothering the
CPU with all  that.
...
 To facilitate this the mainframes typically have fairly
complex  snooping
...
 caches for effective management of paging activity. 

The Crays and ConnectionMachines have, in the past, had the advantage  of
...
 being vector processors where typical mainframes were
often SIMD  machines
...
 at best and simple pipelines at worst. Microprocessors
caught up with  the
...
 SIMD wave with multi-ALU pipelining, and with the
Katmai and AMD-K7  they
...
 will get many of the vector features that made
so-called "super  computers"
...
 so fast. 

If you build a "PC" (Pentium II class) with 256MB of SDRAM and dual PCI
based fast/wide SCSI controllers running to a striped RAID array of 
"good"
...
 SCSI disks you can "beat" a lot of
mainframes. Of course you best them  with
...
 a $10,000 PC. 

Back to classic computers, it has been said, perhaps apocryphylly(sp?),
that "My laptop has more computer power than NASA used to put men on  the
...
 moon." While it may be true, I've never
actually seen a description of  the
...
 computer resources available to NASA between 1962 and
1969. Does anyone  on
...
 the list have that information?

--Chuck

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