Re: IIc SD/MMC RAM

["David Wilson" <mcs6502@gmail.com>]

kaos116 wrote:
> Yes there is a memory expanision header inside. from what I have read and
> remember. All of the ][c's had it except the very first revisions. I think
> you could get up to 1 meg inside.

There would be many more IIc computers without the memory expansion
slot (I have only one memx motherboard vs 5 original IIc units). There
were a number of memory cards designed for the older IIc from companies
like AE (the Z-RAM series plug into the CPU and MMU sockets to gain
access to the required signals and act like auxiliary memory instead of
a "slinky" ramcard.

> My idea is to have a very small unit that attaches directly to the back of
> the ][c and has a pass through for adding additional floppy drives.

In that case it has to be SmartPort compatible (as only one external
Disk ][ type can be supported).

> I want it to be completely Prodos compatible. Meaning no special drivers. You plug
> it in an Prodos sees it and knows what to do with it. This would also make
> it compatible with the ][e/gss'. From what I have been reading in the Prodos
> Tech Ref Manual and Beneath Prodos. Their doesn't seem to be limit to the
> size of a volume.

ProDOS 8 has a 65535 block limit per volume (32MB) {the interface can
handle 65536 but the filesystem cannot use the last block}. SmartPort
uses 24 bit block numbers so 8589934592 blocks (8GB) can be accessed
(or partitioned up into smaller chunks).