Hi Bret,

> USBDRIVE does not try to "virtualize" the sector sizes as others are
> suggesting here as a possibility -- I figure doing that has the
> potential to cause as many problems as the alternative...

Maybe you could make that configurable, so people can experiment
with virtual 512 byte sectors at their own risk? Might be useful
for people who want to make their disk oriented tools 4k-wrapped-
to-512-sane :-)

> Likewise, it will "ignore" disks with sector sizes larger than what
> DOS says it can handle... comment that shows you how you can modify
> MS-DOS and IBM-DOS to handle sector sizes larger than 512 bytes.  It
> involves using DEBUG (or something similar) to modify the DOS kernel

I was not aware that it was THAT easy... I mean for example the
low disk transfer buffer in SDA... If you make it larger, other
things will change their offset, which may confuse other apps /
drivers... But then, I am no expert for *MS* DOS kernels :-)

Can you send the URL of that MS DOS patching instruction? I am
wondering how much it could tell us about how to patch FreeDOS
but of course FreeDOS already is known to have a bit more hard
coded "512 byte ish ness". On the other hand, FreeDOS sources
are easily available and easy to read... :-)

> (MSDOS.SYS or IBMDOS.COM).  I don't know if the same method will
> work with FreeDOS or not.  With the modification, DOS itself can

I do want to know :-)
> supposedly handle sector sizes up to 8192 bytes

Interesting. Any known side effects? Of course it will
not help tools like FORMAT or CHKDSK unless they already
are sector-size flexible. In that sense, I still think
it will be pretty useful if the KERNEL can handle FAT
file systems on virtual-512-byte-sector drives with 4k
sector size, even if e.g. FORMAT would not.


PS: I think for virtual-512 you only need to recalculate
the BPB values in the boot sector before you show them to
DOS (only works for FAT anyway). For the rest, it SHOULD
not matter much whether you R/W a 8*512 or a 1*4096 chunk.

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