Re: How many...models/types: APPLE ][ computers?

[dempson@atlantis.actrix.gen.nz (David Empson)]

In article <3eafc5$iml@acme.freenet.columbus.oh.us>,
Dave Althoff <dalloff@freenet.columbus.oh.us> wrote:
> Okay, some clarification on the early ]['s...
> 
> THE Apple ][ did NOT have Autostart ROM; that's what the screenfull of
> question-marks was all about.  As for DOS 3.2, that was a limitation of
> the Disk ][ drive, not the computer itself.

Actually, it was the controller that was limited, not the drive.  The
drives may have required a little better tuning to handle 16 sectors.
Can anyone confirm this?  It was before my time.

The upgrade to 16 sectors involved swapping the P5 and P6 PROMs on the
disk controller (boot ROM and logic state sequencer).

> blocks, stacked on top of each other.  Incidentally, this is why double
> lo-res does not require a 128k ][e.

But it does require an 80-column text card (1k of RAM in auxiliary
memory from $0400 to $07FF).  The IIe has no firmware support for
double lo-res.  I think the IIc does, and the IIgs definitely does
(even from Applesoft).

Interestingly, Apple have never officially documented anything about
double lo-res mode.

> As for running DOS 3.2 programs on a 16-sector disk drive, the actual
> program is BOOT13

That was a later addition.  The original method was to boot the
"BASICS" disk, I believe.  It then asked you to insert the DOS 3.2 disk
and booted it.
-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand