Re: What 3.5 drive will work with my //c?

[spec@vax2.concordia.ca (Mitchell Spector)]

In article jsassman@binary.net writes...

>My ][C says '0' when I enter that basic 'program'--
>PRINT PEEK (64447)....But it has both a Rom upgrade
>to use the Unidisk drives--I currently have two of
>them connected, AND it has the Applied Engineering
>Z-Ram Ultra 1 meg board....But according to your
>post, Nathan, this model should not be capable of
>memory expansion.  If that's correct, then when I
>run Appleworks and it says I have a desktop of some
>644k available it must be kidding around?? ;)

    Nathan was correct, the original Apple IIc motherboard (ROM '255' 
and '0') does not have any memory expansion socket. Apple designed it
as a closed system with no internal expansion, leaving just the back
port connectors as the only way to make it grow. However, people came 
up with ideas, creating hardware "hacks" to get around that limitation.
The AE Z-Ram board was one such example, you removed the 65C02 and MMU
chips off the motherboard, plugged the board into those sockets, and
then moved the chips onto the expansion board. This little trick let
the non-expandable IIc add more (bank-switchable) memory.

    A few years later Apple saw there was interest in expanding the 
IIc, so they came up with a new motherboard design that included a
memory expansion socket. This new motherboard used the ROM '3' and
ROM '4', and accepted Slinky-type memory boards. When the Apple IIc+
was introduced, it too had a memory expansion socket, but it wasn't
quite compatible with the older memory expansion socket of the ROM
3 and 4 IIc (and the reason my IIc+ still only has a measly 128K of
memory at the moment :/).

Mitchell Spector
spec@vax2.concordia.ca