On 10/8/2011 11:42 AM, Rich Braun wrote:
Jerry Feldman mentioned an old computer:
My first home computer was an Apple II (1978). What Jobs saw back
then was that a desktop computer could be useful to real people.
At the time, there were a few hobby computers. I almost bought a
MITS Altair
The first desktop I ever ran across was in my math teacher's class in
Arlington, VA in 1977:  an HP 9830A (you can find pics of it via Google).
Anyone else remember those?  It had 4K of RAM, kept your programs on a
cassette tape, printed out (quickly) on an 80-column wide thermal printer.
You programmed it in BASIC; I remember writing a banner printing program and a
biorhythm chart generator.

Being exposed to bigger mainframe computers starting around '72, I never
thought of these micro things as anything other than toys.  So when the TRS-80
and Apple ][ came out, they held little interest for me--my first
factory-built (i.e. not cobbled-together) home computer was a 1982 DEC surplus
PDT-11/150; it ran RT-11.  The first "real" home computer, that rivaled
mainframe performance, came along about 10 years later:  the Intel 486.
That's when speed-of-light constraints came to favor microchips over the
"frames" containing CPUs in multiple circuit boards spread across a backplane,
and transistor density has accelerated ever since.

By the time of the 486, Linux was available: today's supercomputing clusters
usually run Linux.

-rich
Speaking of RT-11, my first job out of college was in the Small Systems Group at DEC from 1972 to 1977. RT-11 was developed as a successor to OS-8. The PDP-8 (12-bit word, 3-bit opcode, maximum memory 32K-12-bit-words) was to the world of computers in the early 1970s what the Model T had been to the world of automobiles in the 1910s. While it was severely limited compared to mainframes of the day, the PDP-8 brought the price down to the $10,000 to $20,000 range, a price where every college psych lab could afford their own computer to monitor experiments and process data.

DEC's mainframe at the time was the PDP-10 (36-bit word, 9-bit opcode, maximum memory 4M-36-bit-words), which typically cost many hundreds of thousands of dollars. TOPS-10, the PDP-10 operating system, time-shared among lots of terminals. I don't remember what its limit was, but I think 50 users at a time was not unusual.

When I joined DEC's Small Systems Group, one member of the group was legendary -- Ritchie Lary. PDP-8 development had to be done with a cross-assembler running on the PDP-10. But the Small Systems Group didn't have enough PDP-8's for everyone to have one, so we each got a few hours a day on the real PDP-8 hardware. It was extremely cumbersome to have to assemble your source code on the PDP-10, punch a paper tape of the binary, wait for your 2-4 hour time slot on the PDP-8 hardware, load the binary from paper tape, debug your code, and then have to go back to the PDP-10 and repeat the process if you needed to change anything in your code. The story was that a year or two before I joined, Ritchie Lary realized that to do a standard edit, compile, and debug cycle all on the same machine, he'd need a single-user version of TOPS-10 running on the PDP-8. So he went off and wrote it! Other members of the group wrote the necessary utilities. The editor (TECO) was translated, instruction-for-instruction, to the 8 instuction set. Someone wrote a native PDP-8 assembler. And thus was OS-8 born! Lary's original name for it was the _*F*_ully _*U*_pward _*C*_ompatible _*KE*_yboard _*M*_onitor. Of course, marketing couldn't call it FUCKEM, so they gave it a more respectable name.

I know that if someone had suggested to me at that time that an OS that ran in Mega-words of 36-bit word memory could be implemented as a single-user verison in 8 Kilo-words of 12-bit word memory, with only 256 words resident, I'd have thought the idea was insane! I've always felt that Lary's ability to see that such a thing could be done and go do it was true genius.

Around 1973 or 1974, DEC's hardware engineers gave us a brand new, and quite innovative architecture, the PDP-11. Its instruction set was nicely orthogonal so it was easy to learn, but was also quite powerful. Its native post-increment and pre-decrement addressing modes inspired C's ++ and --.

Our managers came to us and said that because OS-8 was doing so well, they need OS-8 reimplemented to run on the new PDP-11. That's how RT-11 came into existence.

Gary Kildall's CP/M started out as his own reimplementation of RT-11 for the Intel 8080. A few years later, Tim Paterson of Seattle Computer Products (SCP) wrote his own implementation of CP/M called QDOS (Quick and Dirty OS). Bill Gates didn't write MS-DOS. He simply bought rights to QDOS from SCP for $50,000 while keeping secret from SCP the fact that Microsoft's customer was IBM! And that's how the whole chain of cloning and incremental improvement came to make a fortune for Gates under the name MS-DOS.

For me, the lessons of this history are:

   *

     Good software usually involves someone with a brilliant insight
     followed by a series of incremental improvements done by
     individuals, either collaborating with one another or
     unintentionally collaborating by copying and improving each
     other's work.

   *

     Those who reap the rewards seldom have a significant hand in the
     creation.  Instead they tend to be skilled publicists who make
     dubious deals with naive programmers.

I think some, but not all of this, applies to Steve Jobs too. He was definitely quite skillful at promoting his company, their products, and himself. He didn't invent the modern bitmapped graphics computer. That work was done by people like Charles Thacker, Alan Kay, Douglas Engelbart, Robert Metcalfe, and others that most people have never heard of. But I think Jobs had vision that allowed him to improve on their ideas while copying what they'd done, just as Kildall improved on what we'd done at DEC, and Paterson improved on what Kildall did. In that regard, whatever other objections I may have had to how Jobs ran things, I have far more respect for him than for Gates.

           Mark Rosenthal
           m...@arlsoft.com <mailto:m...@arlsoft.com>

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