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Re: Apple II IDE interface
Hi,
> A ProDOS block driver (preferably in ROM on the card, to avoid having to
> load any patches) would allow the card to work automatically with
> ProDOS-8, GS/OS and Apple II Pascal 1.3, with the catch that you are
> limited to two 32 MB partitions, as you mentioned.
You're right, but...
- I want to be able to R/W the HD in a PC (to make CD backups of my
42195742592431592354 floppies around)
- having a ProDOS (or UCSD or CP/M) driver is not contradictory to my
approach, each of them will be stored in partitions, the driver will
do the mappings.
This could be done at least w/ two approaches :
- having a single FAT partition, accessed at the same time either on a
per-file basis, or on an emulated volume basis (emulated volume = FAT
file containing a virtual volume, which could be ProDOS, CPM or
DOS3.3)
- having a partition type for flat file access FAT partitions, another
type for CP/M, another type for DOS3.3 virtual floppies etc. BUT
sticking with MBR partition scheme, and relying on FAT inside the
virtual volume partitions, so that you can still use/edit the contents
w/ other platforms.
> An even better option: write a SmartPort block driver in firmware on
the
> card. This will allow ProDOS-8 2.0.x to access up to 10 or so
> partitions (depending on the contents of other slots) and would
allow
> GS/OS to access multiple and larger volumes.
Sorry, but even if I own a 2GS, I don't know much about it (while I
know a lot about the IIe), and I want the system to run in IIe's as
well as in other II's. My approach does not limit partition sizes
(nor partition number), it is compatible w/PC MBR so you can plug the
HD in the PC and manipulate the blocks, partition table etc. w/ PC
tools, this will ease development and may allow you to do things like
editing your 6502 assembly code w/ Microsoft Visual Studio, assemble
it w/ Procode in a II emulator on the PC, then plug the HD in the
Apple and run the file ! I think this is a sexy approach.
By the way, what is SmartPort ?
> I suspect that having either a ProDOS driver or a SmartPort driver
would
> require adding some RAM to the card, so the firmware can store
> information about the partitions detected on the drive(s).
This can be stored in the II RAM somewhere, isn't it ? All DOSes for
the Apple do things that way. I already use "screeen memory holes"
associated to the slot in which the board sits to put things like
current cylinder, head, sector.
> The ultimate option: also write a native GS/OS driver, allowing
GS/OS to
> get much better performance when accessing the drive.
Sure, but I don't have a clue about this, and I want to use the system
in my IIe.
> On the other hand, there are already other IDE cards out there which
> have these features (notably the Focus), so it would be rather a lot
of
> work for a limited user base.
This is a hobby project, I don't care about "user base". Making any
project on the Apple II can not be anything else than a hobby project
by now, don't you think ?
This does not compete w/ commercial products. My design will be made
available for free as soon as the necessary housekeeping on schematics
and photos will have been made (by the end of next week since I'm on
holiday then). Anyone will then do whatever he wants to do with it.
There might be also Ethernet boards somewhere for the IIe (even if I
never came across one of them), but my next project is making my own
for cheap and coding a TCP stack, so that I can then make small
versions of ELM and Lynx. I dream of it, it is my only motivation on
these projects. The HD basic software should be designed to allow
efficient use of small overlays to be able to keep all this in the
654K footprint, yet interesting things to design and make up !-)
--
St�phane GUILLARD - stephane.guillard@steria.fr
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A4K3.9/CSPPC233-060+CVPPC+128M+4.3G+32x/PicassoIV-Concierto-Paloma/AriadneII