Alto II (was Re: PDP-8 prices

From: Derek Peschel <>
Date: Mon Jan 25 18:40:22 1999

> Apart from that, there's a serious band of PERQ-fanatics who can solve
> just about anything you're likely to come up against and then some :-).

I like good documentation. Clearly, even if the original documentation was
abysmal, information is now pretty readily available. (I think you made
that point in one of your other posts.)

> Sounds like an RK05 pack. I seem to remember the drive looks like a Diablo
> model 30 (for which repair manuals do exist). That would use the same
> sort of pack as an RK05, but these packs are hard-sectored, and I have no
> idea how many sectors an Alto is expecting...

I know the Alto drive is a Diablo drive.

Some Altos came with an option of one removable and one fixed pack. Both
packs have the same capacity. The access time is much lower than the
removable-only machines. (That could be average access time -- meaning that
the removable packs are the same on both kinds of machines. I'm just
quoting from a little table in the manual.)

Some also came with an external removable-pack drive. (The scale is some-
thing I'm not used to. I think of a device I can hold in my hand being
added to a machine that fits on my desk. Here we have a device bigger than
many modern computers being added to a machine that could BE my desk, if the
monitor were taken off the top.)

If you look at the Alto manual, you can see Diablo's model numbers.

> Did all Alto machines have a chording keyboard? Or was it an option?

Possibly an option. The I/O was very flexible but I suspect (drumroll) you
had to write your own microcode for it. :) And create a custom cable and
header. But it could actually have been standard.

The keyset is exactly as Doug Engelbart designed it: 5 bars next to each
other, a bit like piano keys. It doesn't replace the regular keyboard;
it's just an alternate way of entering small bits of data while you use the
mouse with your other hand.

-- Derek
Received on Mon Jan 25 1999 - 18:40:22 GMT

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