Hi folks!
I was wondering about how SvarDOS uses INT13h to detect Disks. Not all BIOSes maps USB disks to INT13h, for example, but some does. SvarDOS can see/map this disks as DOS drives to FDISK?
Is SvarDOS using only INT13h to get disks?
Thanks for your comments.
FDISK relies on INT 13h, hence yes - it should see any drive as long as the BIOS presents it through INT 13h. Same goes for the EDR kernel. On many PCs you have to enable something like "USB legacy" or "USB HDD emulation". Also, the stick must be connected before POST for the BIOS to wire it in.
The EDR kernel seems to use also some INT 11h calls in drbio/disk.asm, but as far as I can tell this is only used for detection of floppy drives.
Mateusz
So, can a TSR add more drives to INT13H table? Does Panasonic USB driver / Adaptec ASPI manager work this way?
https://winworldpc.com/product/dos-usb-support/1x
A TSR can overload INT 13h calls, but this won't be enough to make the drive visible to the EDR kernel since disk discovery is performed at boot time. Such a TSR would also need to fiddle deep into DOS internals. It is much easier to expose a new drive through a device driver rather than a TSR.
The Panasonic USB driver is a device driver (*.SYS), not a TSR.
Mateusz
Sorry, I forgot these concepts... it is too much time... :-)
I will search about DOS device drivers... I don't recall exactly how they work internally. For example, I don't recall if they run only when the device is requested or not at DOS, and so on.
Thank you!
Well, I found the page below... It appears to be the magic solution, but... Will it work with SvarDOS (and potentially FAT-32)? only testing will tell...
https://www.dosdays.co.uk/topics/usb_support.php
FWIW, for me, the Panasonic driver was able to recognize the Sony PRS-T1 e-reader, which is FAT32-formatted (2 partitions). It was not straightforward at all to use, quite cumbersome and slow IIRC, but it worked for transfering files.
I tested this several months ago, though, and then gave up on that driver so I can't remember all the details.