Alto II (was Re: PDP-8 prices

From: John Amirault <amirault_at_epix.net>
Date: Mon Jan 25 23:28:01 1999

Hi,
In order to read a PDF file you need to get " adobe acrobat reader " . Just do
a net search and you will find all the info you need. Hope this helps you.
John Amirault

Derek Peschel wrote:

> > The problem with the PERQ manuals was that they didn't explain things.
> > They expected you to already know it, and just need reminding about (say)
> > the microcode fields...
>
> Weren't there documents that explained everything, but were internal only?
> Of course that is a huge problem when companies go out of business.
>
> > > If you look at the Alto manual, you can see Diablo's model numbers.
> >
> > ...which is a pdf file, which I'll have trouble reading...
>
> hmm. I've never seen that info except on the one site. You may just have
> to find a way to read those files.
>
> I wouldn't say they're complete (especially by your standards), but they're
> better than the information which I previously had, which is almost none.
> So they're worth reading.
>
> > All PERQ I/O is done in microcode as well. To give you some idea of what
> > it looks like, here's some microcode to implement a centronics interface
> > on the optional PERQlink port
>
> > {Centronics driver microcode for standard parallel printer on the PERQlink}
> > {interface.}
>
> Why do I suspect the microassembler syntax was based on Pascal's?
>
> (I had written "microsyntax" but that's not really the same meaning.)
>
> > Am I correct that the Alto keyboard was scanned in microcode, and that
> > selecting which file the machine booted from was done by holding down
> > some of the keys during the boot (the 16 bit? number from the keyboard
> > was ORed with the disk address or something).
> >
> > If so, then it was possible to have boot files that were almost
> > impossible to boot from because of the keys you had to hold down. They
> > were generally known as 'nose-boots' for the obvious reason.
>
> Yes, you are correct. See my huge reply to Sam's small question ("Why not
> just create a microcode emulator?").
>
> Maybe they assumed you wouldn't need that many boot files anyway. Probably
> several would suffice: the Exec (OS and shell), the Scavenger (disk repair),
> the NetExec (Exec with network file capabilities), the FTP program, a disk-
> creation and copying program. IIRC those were all available, and that's
> about all you need, I think.
>
> > Alas the PERQ makes it less fun. They keyboard is handled in hardware.
> > You do select the boot image by holding down _a_ key during the boot,
> > but it's only one key, so there's no problem.
>
> :) You still have 50-100 options to choose from (one per key). That's not
> as many as 256 (128? 65536?) but it's still a lot.
>
> I wish modern machines had useful and flexible boot-time options. The IBM
> RS/6000 does (but being IBM, everything is done with the function keys).
> Other workstations do. Home machines don't, but their device interfaces are
> so complicated that they should. The shortcuts on the Mac are a good start,
> but I'm talking about documented, powerful, consistent firmware, to the
> level of a mini-OS if necessary.
>
> -- Derek
Received on Mon Jan 25 1999 - 23:28:01 GMT