Paste #F6P -- näytä pelkkänä tekstinä -- uusi tämän pohjalta
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | 13:03 < Sompi_> Now I also noticed that on some BIOSes the boot drive number is randomly sometimes 0x80 and sometimes
0x00 when booted from a USB storage stick. The number seems to be consistently the same for the same USB
stick and BIOS but otherwise seemingly random
13:04 < Sompi_> It is a problem, because if the boot driver number is 0x00, the kernel assumes that it is booted from a
floppy, and does not even try using LBA or detecting the disk geometry using int13,8. Then it tries to
use the geometry in the FAT boot sector that of course does not work, because it is not the real geometry
for the USB stick.
13:05 < Sompi_> How the hell do I fix that...
13:06 < Sompi_> How can the USB booting be so broken on so many modern BIOSes
13:07 < Sompi_> Those BIOSes just randomly decide to assign drive number 0x00 for some USB sticks, and number 0x80 for
some others
13:07 < Sompi_> And according to the BIOS specification 0x00 should ONLY be used for floppy drive 0
13:18 < Sompi_> And because floppies are soft sectores and the BIOS doesn't know anything about their geometry, the
kernel has to work differently with them than it does with hard drives
13:37 < Sompi_> And also those BIOSes often report that the computer has one (1) floppy drive, when in reality it has
none, and that breaks even more things
13:42 < Sompi_> So: The BIOS reports that the computer has a floppy drive, when in reality it doesn't. The BIOS also
assigns drive number 0x00 to the USB drive that it's booting from. How should the kernel know that the
drive 0x00 is NOT the floppy drive that actually doesn't even exist, but instead a USB storage device
that has a hard-coded geometry that must be determined with BIOS int13,ah=8?
13:42 < Sompi_> ACPI is not a solution, because it is also utterly broken on many implementations
|