Re: Booting from ProFile on IIe possible?

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

In article <3hareq$nh4@cello.gina.calstate.edu>,
Greg R. Achenbach <lacoss@cello.gina.calstate.edu> wrote:
> The subject line pretty much says it.  I hooked up a 5 meg ProFile to a 
> IIe last night.  It seems to work fine, but I can't boot from it.  I 
> tried putting the interface card in both slots 5 and 7.  The only thing 
> that happens is the 5.25 drive (a DuoDisk) attempts to boot every time.

Matthew Pierce's suggestion is correct.  The ProFile will not boot
automatically in an unenhanced IIe (or a II+).

You can boot it manually by pressing Control-Reset while the DuoDisk
is spinning (this should drop you into BASIC) and typing PR#7 if the
card is in slot 7 (if not, use the appropriate slot number).

If you get your IIe enhanced, it will be able to automatically boot
from the ProFile, provided the card is in a higher numbered slot than
your DuoDisk card.


The reason for this behaviour: the II+ and unenhanced IIe look for a
bootable device by checking four ID bytes in the ROM of each card.
These bytes are at $Cn01, $Cn03, $Cn05 and $Cn07, and their values are
$20, $00, $03 and $3C.

These are the ID bytes of the Disk ][ controller card, and compatible
cards.

The ProFile matches the first three ID bytes, but the fourth one
contains $55 (this was probably to allow software to easily identify a
ProFile).  This prevents the unenhanced IIe and II+ from recognising it
as a bootable device, so the computer skips that slot and tries the
next one.

The enhanced IIe and IIgs only check the first three ID bytes, so they
will boot from the ProFile.

Note that SmartPort interfaces (including 3.5" drive cards, standard
slot memory expansion cards and SCSI cards) will also not boot in an
unenhanced IIe or II+, but work fine in an enhanced IIe or IIgs.
SmartPort devices can be identified by the fourth of the disk ID bytes
containing $00.
-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand