Re: Hardware idea

["Terence J. Boldt" <apple2@geekmag.net>]

> How difficult would it be to make an Apple II block device card that
> had the following:  a SIMM or DIMM slot for a 32M memory card, a ProDOS
> block driver (in ROM) and possibly a NiCd or Lithium (or whatever)

As others have mentioned, SIMMs and DIMMs are power hogs and will require
extra circuitry for handling the refresh timing as well as breaking up the
32 bit or 64 bit data into 8 bit.

I was starting to work on a static RAM drive but it's not cheap to build.
The EPROM based solid state drives I built
(http://apple2.geekmag.net/romdrive.html) cost me about $50 ~ $55 USD to
produce in small quantities.  Prices of 1 MB EPROMs have gone up since then.
Static RAM used to be available up to 512 K x 8 but now I can't find
anything bigger than 128K x 8 (for about $5 USD) so to get even a meg, you
need $40 USD worth of chips just for the RAM.

> I am thinking that the block driver could fit in it's entirety in the
> cx00-cxff ROM space (only 256 bytes needed).  It would bank switch the a

I got my drive working in the $Cx00 - $CxFF memory space using 189 bytes
plus a text copyright message.

> Will GS/OS be able to use this device if it contains just a standard
> ProDOS block driver?  Based upon the recent post about a home brew IDE

Yes, I booted my IIgs with my ROM-Drive and it uses standard ProDOS block
driver code.

> I think that this IO card would be absolutely cool.  A completely solid
> state hard-drive.  I suspect that it would be faster than any non-DMA
> SCSI card out there.

Solid state is the way to go for speed and reliability but at the expense of
price and storage space.

I'm reading up on USB right now.  I realise that building a USB host card
for the Apple II is all but impossible now.  Fortunately it wouldn't be too
difficult to build it as a USB device.  Confused?  I was thinking about
building a card for the Apple II that from a PC/Mac perspective, it appears
as a standard USB device but from the Apple II's perspective, the card looks
like a ProDOS block device.  Then some simple code on the PC/Mac could
emulate a ProDOS hard drive.  Why not use parallel or serial?  USB is
certainly more complicated but it will be around longer in the future.
Also, building a USB device sounds like fun.

> The three most dangerous things are a programmer with a soldering
> iron, a manager who codes, and a user who gets ideas.

I must be dangerous...  I'm a programmer with a soldering iron...  ;-)

-- Terence J. Boldt