| File: |
IDEFAT16.TXT - 18/06/2000 |
| Subject: |
FAT16 driver for Sunrise MSX ATA/IDE interface
|
| By: |
Jon De Schrijder (jon@msx.ch) |
If you want to use FAT16, read this text carefully !
On a normal MSX system, only the FAT12 filesystem is supported. With that
filesystem, the maximum size of a drive(letter) is 32MB. When using a FAT16
filesystem, a drive can be approx. 2GB. To support FAT16 on the MSX, you need to
install a FAT16 driver.
This text contains some additional information about the FAT16 driver made by
Okei. The latest version of her driver (ver 0.07b) supports both MegaSCSI and
IDE. It is still in a beta stage because Okei expects some problems with
MegaSCSI. For IDE, everything seems to work perfect.
To use the FAT16 driver with IDE, you need IDE bios version 2.00 or higher.
The FAT16 driver is installed simply by running the FAT16.COM program. This
program patches the DOS kernel in order to support the reading and writing of
FAT16 formatted partitions. If 1 primary mapper RAM segment is available, it
will be allocated by the FAT16 driver to perform caching.
This driver remains active until you reset your MSX or until you uninstall the
driver by running FAT16 with /R option. Uninstalling can be useful to free the
RAM segment that was used for caching.
As long as the driver isn't installed, the drive(letter) to which a FAT16
partition is assigned, WILL NOT WORK PROPERLY. WRITING DATA TO THE FAT16
PARTITION IF THE FAT16 DRIVER IS NOT INSTALLED, WILL CERTAINLY CAUSE DATA
CORRUPTION ON THE FAT16 PARTITION!
When the driver is installed, all FAT16 drives in your system will behave like
normal drives.
Some programs will need a patch to work properly with a FAT16 drive. One of
those programs is COMMAND2.COM, the MSX-DOS2 commandline interpreter. One of the
problems is the internal command DIR. Without a patch, it will not display the
correct amount of free diskspace. There is already a patch available:
PATCHCOM.COM (Made by Okei and Manuel Pazos) It will solve the DIR problem. Just
run the program in the directory where your COMMAND2.COM is in. This has to be
done only once. (watch out: a patch of COMMAND2.COM version 2.4x is not
supported, only version 2.2x or 2.3x)
There are no known problems with the other internal commands (COPY, TYPE, ...),
except with CONCAT. CONCAT might not function properly when handling large
files, but more details are unknown. If you want to play it safe, don't use
CONCAT on FAT16 volumes.
There are other programs, like CHKDSK.COM, which won't work properly on a FAT16
drive. Don't use it.
Also Multi Mente need a patch to work ok:
MM.COM ver 2.07A
Address: 3D5Dh
Change : 'CAh,4Ah,3Eh' to 'C3h,4Ah,3Eh'
MM.COM ver 2.07K
Adrress: 3E0Fh
Change : 'CAh,FCh,3Eh' to 'C3h,FCh,3Eh'
Please use DOS COPY command when coping files.
The FAT16 driver can work together with IDECDEX without problems. So it is
possible to copy files from CDROM to a FAT16 partition :)
When the FAT16 driver is installed, some BDOS functions will not be available
anymore: #14, #15 (FCB sequential read/write), #67 (format routine) and #68
(creation/destruction of RAMdisk). When these are called an invalid MSX-DOS call
error will be returned. So it is not possible to format disks or create/destroy
a RAMdisk when the FAT16 driver is active. If you want to do such action,
uninstall the FAT16 driver first (FAT16 /R).
Note: using a RAMdisk is no problem if it was installed before the FAT16 driver.
As long a IDEFDISK 3.0 is not ready, you will have to create FAT16 partitions on
PC or by manually sector editing. It is also important to note that only so
called 'Primary DOS partitions' will be detected by the MSX.
Last minute tests have pointed out that reading Windows9x FAT16 partitions is
not always without problems. The computer may crash when accessing certain
directories or files. It has probably something to do with long filenames or not
completely deleted directory entries.
Have fun with it !
Jon |
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