

Altair 8800 – Loading 4K BASIC with a Teletype [video] - mmastrac
https://www.youtube.com/watch?v=qv5b1Xowxdk

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kps
Paper tape is why ASCII DEL is 0x7F — it's the only idempotent punch.

And why typing DEL is properly a _forward_ delete operation: it eliminates the
character under the cursor — converting it to a DEL, to be ignored when
reading the tape — and (like any other punch) advances to the next. (I blame
the VT220 for mucking this up and leading to endless confusion.)

~~~
gue5t
All punches are idempotent, in that punch_x(original) =
punch_x(punch_x(original)). ASCII DEL is the only punch that acts as a
constant endomorphism.

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Gracana
I've always been disappointed that I missed out on this era of computing. I
had a couple Apple IIs in the late 90s, and I enjoyed them immensely, but it
was old stuff by then and much of the community was gone, and people had moved
on to newer things.

I have dreams of creating a modern microcomputer. A computer for the hacker
masses, inexpensive with modest specifications and simple design, with ample
parallel and serial IO. Something that puts you close to the metal with few
distractions and limited complexity, like an arduino but interactive and self-
contained. Like what the Raspberry Pi was meant to be, but without binary
blobs and complicated operating systems.

Is that an idea that appeals to anyone else? Whenever I think about it, I feel
all warm and fuzzy inside. I know some of it is nostalgia, but I also think
there is a lot to be said for the creativity and inspiration that arises from
working in simple constrained systems.

~~~
bwldrbst
I'm nostalgic for the days of 8 and 16 bit computing but whenever I sit down
at my c64 or Amiga now I marvel at how far we've come.

That said, I agree that a simple and constrained environment can be great for
learning and creativity. This is one of the reasons I'm currently writing a
Logo interpreter reminiscent of ones I used as a kid in the 80's, using an
Apple Logo II manual as a guide. Hopefully I can get my almost six year old
daughter interested in playing with it!

~~~
voltagex_
Logo! Are you going to open source the interpreter?

~~~
bwldrbst
It's at github.com/adkennan/logo but is still very much a work in progress. My
goal is to get it running nicely on a Raspberry Pi.

~~~
voltagex_
logogo, gologo, goturtles?

~~~
bwldrbst
logo-a-go-go perhaps? I haven't spent much time thinking about a project name
beyond "my logo interpreter that's on github"

Plus, just because it's written in Go I don't think an application should have
extra "go's" in it's name!

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kabdib
I built a Z-80 kit in 1978. My first computer. It was a blast. I still have
the thing.

Before you get me wrong: I was the only kid in my high school with a computer
of his own. That's kind of unbelievable. The next year, there were maybe six
of us with computers. We had all kinds of opportunities because of our early
exposure to this stuff (I arguably got my first real job because of that kit I
built).

[We also got into trouble with modems, and my grades cratered, and I
independently discovered hacker hours. Ha.]

I do get nostalgaic, but every time I go back and want to program one of these
things (e.g., a KIM-1 replica I built last year, and an IMSAI replica) I run
into the fact that the software environment on these things really stunk. That
KIM-1 sits there; I wrote an assembler for the thing in a couple of days, but
dealing with the limited resources _when I don 't absolutely have to_ takes
the wind out of my sails.

If I was on a desert island, I know I could deal. It would be no problem. But
while it's nice to have that to fall back on, I'd much rather be hacking in
C++ / Python / JavaScript with a real editor and a debugger that doesn't suck.

Someday I'll dig that old digital group system out of the closet and get it
running again. But chances are that I'll write an emulator for it first :-)

[I did get to do a nice bit of embedded systems work a few years ago; a little
power control system in 1920 bytes. That was a lark, and I got one of my cow-
orkers roped into the project and we were basically insufferable, giggling
kids for about two weeks, saving bytes and doing dirty hacks to make things
fit in that space. Oh, those poor PMs...]

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robterrell
I remember doing this for my dad... sitting in his computer store, entering
bytes of the boot-loader program by flipping switches. In my memory, it took
much longer than in the video. The computer was an Altair clone, one of these:
[https://www.youtube.com/watch?v=VYhbzCAzNy0](https://www.youtube.com/watch?v=VYhbzCAzNy0)
and the paper-tape reader was also different (not connected to a teletype,
just a stand-alone paper tape reader with a serial port) so I guess it was a
different bootloader entirely.

~~~
femto
At one point I worked on an over-the-horizon radar, where the control room was
at the receiver site, about 100km from the transmitter site. It had changed by
the time I was there, but the old techs used to tell of having to enter the
bootloader, for the computer at the transmitter site, via radio link. If the
link went down, you had to start again...

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JoeAltmaier
My brother built one of those from a kit when I was a kid. I wrote my first
computer game in 8080 assembler, in 128 BYTES of ram.

He donated it to the San Jose tech museum I think.

~~~
linker3000
I was at the museum yesterday and have just checked my pictures - the plaque
next to one of the 8800s says "Gift of Craig Payne", and the plaque next to
the other says "Gift of Louis Wheeler".

Edit: Actually, that was the Computer History Museum at Mountain View. I
haven't done the Tech Museum in San Jose yet.

~~~
JoeAltmaier
Neither of those guys. Richard Altmaier.

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greenyoda
At the end of the video (approx. 8:25), he tells you that the machine is
actually an Altair clone made with modern technology, not a real Altair 8800.

~~~
bodyfour
My first hint was actually at 6:10 when it reported 61399 bytes of memory
free!

~~~
EEGuy
I think that means the (emulated) machine is filled out to a full 64KiB. In
the days of "4K BASIC", and 4KiB memory boards, a full 64KiB would have been
impossibly expensive, but BASIC didn't care: The "Bytes Free" was how much
room was left in RAM for what program you might care to load or toggle in
after the BASIC interpreter had loaded.

Those 4K boards in the original Altair were expensive: $264 kit in 1975 [1].

I do recall the smell of those TTYs: Machine oil, bronze bearings, paper and
ink.

Nice to see those 16 Address Bus switches, with the lower 8 switches doubling
as data switches for the "Deposit" and "Deposit Next" switch.

edited for reference

[1] [http://www.pc-history.org/altair.htm](http://www.pc-
history.org/altair.htm)

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rabino
btw,
[https://www.youtube.com/watch?v=bymOIRg5M9E](https://www.youtube.com/watch?v=bymOIRg5M9E)

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0x0
We've come a long way in just a couple of decades. The gap between the
computer shown in the video, and the ios device I'm watching the video on, is
mindblowing.

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jeffbarr
I have yet to watch this, but I am pretty sure that the first two bytes of the
loader, are 063, 307. I loaded Altair Basic dozens of times as a teenager in
the late 1970's.

Am I right?

~~~
Gracana
"First two bytes are 41 and 256," he says.

How would a byte be 307? Or 256, for that matter. I must be missing something
basic. Hah.

[edit] Oh, octal. Five groups of three plus the one on the end. That makes
sense and also explains how he's so easily plugging in the numbers.

~~~
walshemj
Also DEC PDP's used OCD octal coded decimal - I had once or twice to manually
load the boot strap when our pdp 11/40 boot strap loader subsystem had a
fault.

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vmmenon
wow. surreal ...

