William H. Magill on 10 Mar 2008 10:31:47 -0700

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Re: [PLUG] Virtualization Presentation

On Mar 8, 2008, at 3:36 PM, K.S. Bhaskar wrote:

> On Sat, Mar 8, 2008 at 8:41 AM, Mag Gam <magawake@gmail.com> wrote:
>> Whoa, you are a dinosaur sir ;-) Kidding
> [KSB] Not far off the mark!  The first computer I used was an IBM 1620
> model 1.  RAM was 40,000 decimal digits.  The basic cycle time was 20
> microseconds, and it took a minimum of 8 cycles for an instruction.
> So to add 2 and 2 to get 4 took 160 microseconds (the model 2 had a 10
> microsecond cycle time and took a minimum of 6 cycles).  When IBM
> first came up with the 1620, it was to be called the CADET.  Then
> someone pointed out that CADET is an acronym for "Can't Add and
> Doesn't Even Try".  This was true - it didn't have addition hardware.

Haven't heard "CADET" for years !!!

Did you happen to learn FORTRAN 2 from Decima Anderson(?) on Drexel
Institute of Technology's 1620?

We first learned to program the 1620 in machine code (not assembly)
in that course,  before we learned anything else!

As for the history of Virtualization:

According to the Wikipedia,

"In 1961, Burroughs released the B5000, the first commercial computer  
with virtual memory.[8] It used segmentation rather than paging."

BTW, for those who are fans of Disney's TRON, the "MCP" was the name  
of the Burroughs virtual OS.

Shortly after that RCA introduced the Spectra 70 computer line. The  
70/46 was a virtual machine running VMOS (Virtual Memory Operating
System), which was a virtual memory OS running off a Paging Drum.

"The VMOS paging algorithm: a practical implementation of the working  
set model"
was published by ACM SIGOPS in 1974. It was written by Mark Fogel,  
then of UNIVAC, which had purchased the RCA computer systems division  
in 1972. Univac's OS for the 90 series computers was known as VS/9.

In 1972 when I started working at Penn, I was running Virtual on an  
RCA 70/46 under an os called TSOS, which had just been renamed
VMOS. The 70/46 had a 1 meg (yes 1meg) drum that allowed the 256k main  
memory box to run virtual.

William H. Magill
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