was nearly useless; lots of fixes to qemuppc and pc86 sbrk(), which was broken;
change the pc86 console to echo output to the serial port (needed for running
tests on qemu).
When the bootloader probes the drive geometry, the BIOS can clobber the
es register. If this happens, the bootloader loads the program to the
wrong address, and jumps off the code. This happens with an emulated
floppy drive in Bochs or QEMU, but not with an emulated hard disk.