Re: OT: Computer and chip history (was: Re: [kidsgames] word familiarity)

[Steve Baker <sjbaker1@airmail.net>]

Doug Loss wrote:
> 
> On Fri, 18 Feb 2000, Kidsgames Project Coordinator - Jeff Waddell wrote:
> >
> > Most modern work was done BEFORE the IBM PC existed.  It's only slightly
> > older than I am, I think.  When did IBM bear the PC?  Hmmm.  '67 or is
> > that way too soon... I get the timelines confused....I mean motorla's
> > 68000 chip was named that because it came out in 1968 right?  Or is that
> > urban legend....

HaHa! The youth of today....   :-)

> The IBM PC came out in 1981.  In 1967 a four-function calculator was
> slightly larger than an electric typewriter (for comparison's sake).  the
> 68000 chip didn't come out till the early '80s.  It was an extension of
> their 6800 chip, which was in turn based (if I remember correctly) on the
> Mostek 6502 that powered the Apple ][.

This is getting *WAY* off-topic...but in the interests of historical
accuracy...

The 6502 was a cost-reduced version of the 6800 - not 100% compatible,
and missing a couple of rather important registers.  The 6800 came
first...sometime in 1976 or '77 IIRC.  But everything else Doug says is
correct.

Arguably, the first PORTABLE calculator was built by TI in 1971 (and it
weighed 2.5lbs). I'd have guessed that in 1967, a four function electronic
calculator would have been impossible - using only transistor technology
...but I could be wrong about that.

The first microprocessors appeared in 1975 (the Intel 4004).

Certainly there were no 'home computers' of any description until the
late 1970's.  The "state of the art" in the late 1970's was incredibly
primitive compared to the first IBM PC.  It was more like the 6800-based
computer that I hand-wired myself for home use.

It was my own design and built during my last year in college - which
was 1976/1977.  It drove an ancient (and noisy) ASR-33 teletype. With
only 4Kbytes of RAM and no ROM or backing store at all (bear in mind
that floppy disks had not been invented), it was hard to write anything
complex.  A program to play 'Othello' was the most complex thing I ever
wrote for it.

Because the machine had no boot ROM, you had to key a paper-tape reader
program directly into the RAM (in BINARY) on a set of key switches and
LED's wired up directly to the main bus while the CPU was in HALT mode.
Once you'd keyed in that 30 byte 'bootstrap' program, you'd check it
carefully and then reset the CPU.  It would run the program in RAM which
would load in a 1kbyte program from the ASR-33's paper tape reader.
The ASR-33 could read 10 bytes per second from tape - so the 1 kbyte
'monitor' program took several minutes to read in.

That 'monitor' program would allow you to load and run other programs
either from paper tape or by punching them in (in hex) on the keyboard. 
You could also save areas of memory to paper tape so you could save your
work.

The 'bootstrap' process would take about 5 or 10 minutes - and the
slightest error in a program would crash the machine and force you
to reboot all the way from the beginning.  Suprisingly, it was no
more or less fun than playing with a modern machine...we had much lower
expectations in those days!

My Othello game took about 3kbytes and took over 5 minutes to load from
tape (plus another couple of minutes to wind the huge pile of paper tape
back onto a spool ready for next time!)  Since the teletype could only
print at 10 characters per second, it took quite a while to print out
the board after every move.

Damn - it makes me feel *old*.   :-(

-- 
Steve Baker                  http://web2.airmail.net/sjbaker1
sjbaker1@airmail.net (home)  http://www.woodsoup.org/~sbaker
sjbaker@hti.com      (work)

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