Disk sharing

Hi
I have a two machine configuration with win2000 which shares a scsi
disk.The scsi disk is connected through add on Adaptec 29160 controller
cards.i want to write into the disk and want to access it from the second
machine.i tried writing and flushing using FlushFileBuffers() so that the
data is flushed to the disk. also FSCTL_DISMOUNT_VOLUME from the second
machine so that it dismouts and remounts in the second machine..but this
seems to work sometimes,but doesnt work most of the time..what is the
correct way of doing this?

if i reserve the disk from one machine, still the drive is accesible from
the second machine..is it possible to block access to the disk from the
second machine???

Thanks in advance..
Deeps