Hi! > 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=... Eric ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
