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Re: firmware for the PseudoDisk
Alex Freed wrote:
"Michael J. Mahon" <mjmahon@aol.com> wrote in message
9qKdnYGU25CrM8zYnZ2dnUVZ_rednZ2d@comcast.com">news:9qKdnYGU25CrM8zYnZ2dnUVZ_rednZ2d@comcast.com...
1. Make a Windows GUI that allows writing images to the SD/MMC.
No need for a "filesystem". Just some simple catalog of images that
are always contiguous.
2. Use FAT16 on SD/MMC to store files: .nib images and .hdv images.
Treat them as nibble images and ProDOS volumes depending on
extension. On boot load a program that will list the FAT catalog
and allow selecting an image by name.
How about just making it have multiple ProDOS partitions, and
accessing it with CiderPress on the PC or ? on other platforms?
What is the partitioning scheme for multiple ProDOS partitions?
I *think* CiderPress can only access a single ProDOS volume on
a physical device. And Windows only maps one partition to a logical
device.
There are actually several different methods, depending on the
controller card.
Apple's SCSI cards implement a Mac-style partition table.
CFFA implements "hard" partitions set by the controller, with
no partitioning table.
Other IDE cards implement a partition table on disk, but I
don't know what standard, if any, was used.
The idea here is to make it easy to store images to the flash memory
on any platform. They all understand FAT. Suppose I write 10 .hdv files
up to 32MB each and 10 .nib files 228K each to the FAT-formated SD card.
The firmware lets the user select one image and maps linear sector addresses
to the physical storage according to FAT.
How could ProDOS use a FAT filesystem, anyway?
Same way as Apple emulators use .hdv images on my NTFS drives.
OK, so the ProDOS file system is embedded in a FAT file.
This approach essentially replaces Apple partitions with
FAT files, so only a single FAT partition is needed, with a
file for each Apple "partition". Of course, the FAT files
may not remain physically contiguous, so multiple levels of
block mapping are required (Apple to FAT and FAT to physical).
-michael
NadaNet networking for Apple II computers!
Home page: http://members.aol.com/MJMahon/
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