[Discuss] Old computers Re: (OT) Steve Jobs 1955-2011

[mbr at arlsoft.com (MBR)]

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
            mbr at arlsoft.com <mailto:mbr at arlsoft.com>