> I suspect that your problem is that the NetBSD partition starts after
> cylinder 1024 and that therefore the BIOS (on which the bootloader
> relies) cannot load the kernel.

I only have netbsd on that machine, so there isn't any cylinder 1024 
problem. It's a deeper problem: msdos/windows, and Bios doesn't 
regognises the HD. Only a loaded unix kernel do (without bios 
compatibility ?!).
(40Go ata133 HD for an old 486 is pretty much.. normaly it's not 
possible to get more than 8Go HD on thoses machines).

 > boot -a

is the solution: it gives me the choice to choose the root and swap 
partition and the filesystem (default is generic.. i should write 'ffs' 
right?) but after the kernel loading and dmesg i got that problem:

wsconscfg: /dev/ttyEcfg: Device not configured
wsconscfg: /dev/ttyEcfg: Device not configured
wsconscfg: /dev/ttyEcfg: Device not configured
wsconscfg: /dev/ttyEcfg: Device not configured
wsconscfg: /dev/ttyEcfg: Device not configured

(some other lines, starting inetd, cron and then:)

May 16 14:24:52 getty[179]: /dev/ttyE1: Device not configured
May 16 14:24:53 getty[181]: /dev/ttyE3: Device not configured
May 16 14:24:53 getty[180]: /dev/ttyE2: Device not configured
May 16 14:24:53 getty[178]: /dev/ttyE0: Device not configured


and i can't do anything then, no prompt, no shell, not reboot when i 
type Ctrl+Alt+Del.. i have to turn power off


thanks for you help
help i'm asking again