> In case anyone is interested, we have an article on the FreeDOS site
> about USB from a BIOS engineer. It's a good read (and short) and
> explains why USB hard drives are hard to support properly everywhere,
> while USB floppy and keyboard/mouse is easy:
> http://www.freedos.org/freedos/news/technote/173.html

Nice indeed :-). This engineer writes that keyboard and mouse work
by providing PS/2 style access through int16 (and probably int15?)
and (via SMI) even a simulation of PS/2 hardware... :-). He also
writes that floppy works by providing int13 access and that many
USB harddisks at the time when he wrote the technote are not
standard compliant: That means you cannot boot from them and
the BIOS cannot "drive" them for you.

He also writes that when you load a DOS USB device driver then
it will interfere with BIOS USB drivers and you lose access to
those. That is quite possible, but what are the experiences on
this list? Did any of you lose access to your USB keyboard/mouse
when you started a DOS USB flash/harddisk/... driver, for example?

And if so, did you find a workaround, for example plugging the
keyboard/mouse to one group of USB sockets and the USB flash
stick to another group of sockets? What I already do know is
that USB can have a lot of lag and consume lots of CPU time
compared to real PS/2 hardware, and that sometimes USB or
other things (such as onboard network or sound) use memory
areas which are not automatically excluded from DOS UMB, so
you get a crash when you use them and EMM386 at the same time
unless DOS happens to leave the area untouched or you use X=...


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