Re: If you could design a $300 homecomputer today, what would you choose?

[wbdesnoy@acs5.acs.ucalgary.ca (Byron Desnoyers Winmill)]

Bob Retelle (bobr1@provide.net) wrote:
: Allied Electronics doesn't even stock them any more, but for only $200
: they'll order you a 33Mhz 68020 chip.

That price is insane, and I suggest that you shop around more.  And focus on
the 68000, which I have seen in calculators costing about US$120.  I am
quite confident that the manufacturer is not producing these at a loss, and
likely have a healthy margin.  One of these calculators served as my
inspiration, only with boosted I/O capabilities, much more open design,
and with the OS in ROM where it can not be damaged.  (I pulled mine apart, and
it used a Motorola 68000.)

I will not argue withthe PB100 hypothesis though, as I am a Mac user. 

It is worth noting though that only parts of the Macintosh and IIgs operating
systems are in ROM.  For the machine to be in a useable form, the rest must be
loaded from disk (the Classic was an exception, but even it does not spring to
life as an Atari ST would).  Indeed certain drivers required to access the
original Macintosh hardware do not appear to be in ROM, including part of the
serial driver, the print manager, and the AppleTalk manager.  (From Inside
Macintosh Vol. I.)  details are bound to be different for later models, such as
the PB100, but I would imagine that (proportionally) less was integrated into
later versions of the ROM.

Now why is that relevant?  Well, I would want the whole OS in ROM.  That way,
if you goof up while creating patches, you simply reset the machine (or, better
yet, disable patches while booting in order to recover your data).  This calc
of mine (with the OS in flash memory) has given me a scare a couple of times,
and certain parts of its software do not appear to work correctly to this day.
It is, of course, poorly documented so that is a problem too.  Hopefully the
ROM would be socketed, so that the OS could be upgraded (or the patches
incorporated in some optimised form).*  But that is not a huge issue.  The
other reason for a ROM based OS is to avoid the lengthly process of
reinstalling the OS, as I'm certain many of you Windows users enjoy.  ;-)  The
patches would have to be reinstalled, but your machine wouldn't be in an
unusable form without them.  If the patch installation system is sensible,
they should be quite easy to copy from a floppy disk to a system folder anyway.

Byron.

[*] Come to think of it, wouldn't flash memory have a write enable line?  If
so, a manual switch or jumper on this line would be a suitable alternative.