> Deng Hongwei writes:
> > When install NetBSD 1.3 BETA(Final) from floppy(dd from boot.fs) in IBM
> > ThinkPad 755CX Laptop, It can't boot at all, the machine only reboot
> > again and again whih nothing prints on the screen except:
> >   16000 kb ok
> 

I've debuged the bootsect and boot file of NetBSD 1.3(i386) in my IBM TP 
755CX, The following is the result:

1.The installation floppy's bootsect goes correctly, and success loads
the
  'boot' file;
2.Then the procedure jumps to boot's code and goes to 0100:0400 (the
entry
  of function 'real_to_prot') and failed at 0100:0411

  0100:0400  FA		        CLI
  0100:0401  67660F011500010000 LGDT FWORD PTR [00000100]
  0100:040A  0F20C0		MOV  EAX, CR0
  0100:040D  6683C801           OR   EAX, +01
  0100:0411  0F22C0             MOV  CR0, EAX       ---> break here.
                

Then I tracked the FreeBSD and OpenBSD's boot code, and found the 
procedure is almost the same, except they define 'BOOTSEC = 0x1000' 
( which NetBSD define 'BOOTSEC = 0x0100), So I wonder if the IBM 
TP755CX doesn't support using 0x0100 segment when booting?

I want to do some test about this( let BOOTSEC = 0x1000 in NetBSD ),
but I don't know how many codes relative to it, how to make a boot 
floppy, and where should I be in to build the install floppy(
'sys/arch/i386/boot/biosboot' or 'sys/arch/i386/stand')?