Most MACHINE machines usually need little or no preparation before installing OpenBSD, other than the usual, well advised precaution of BACKING UP ALL DATA on any attached storage devices. You will need to know the SCSI target ID of the drive on which you will install OpenBSD. It might be a good time to run the diagnostics on your MACHINE. First, attach a terminal to the "ttya" serial port, then set the "Diag/Norm" switch to the Diagnostic position, and power-on the machine. The Diag. switch setting forces console interaction to occur on ttya. The console location (ttya, ttyb, or keyboard/display) is controlled by address 0x1f in the EEPROM, which you can examine and change in the PROM monitor by entering "q 1f", then a numeric value (or just a '.' if you don't want to change it, and "q" again to return to the prom). Console values are: 00: monochrome framebuffer (on-board or VME) 10: tty a (9600-N-8-1) 11: tty b (1200-N-8-1) 12: color framebuffer 20: color option board on P4 (model 3/60 only) OpenBSD will use the EEPROM setting to determine which device to use as the console, so you should make sure it is correct. Please note that while OpenBSD and SunOS have a reasonable degree of compatibility between disk labels and filesystems there are some problems to watch out for during initial installation or when trying to maintain both OpenBSD and SunOS environments on the same system. If the OpenBSD fsck(8) utility is used on a SunOS filesystem, it will set OpenBSD "clean flags" and BSD4.4 summary fields in the superblock. SunOS does *not* like this and you will have to do a "fsck -b 32" under SunOS to access an alternate superblock to repair the filesystem. You should always specify SunOS filesystem with a "pass number" of 0 in their /etc/fstab entry to prevent this, and preferably mount them "RO". If SunOS fsck is used on an OpenBSD filesystem in the default OpenBSD (4.4BSD) format, it will first complain about the superblock and then about missing . and .. entries. Do *not* try to "correct" these problems, as attempting to do so will completely trash the filesystem. You should avoid using softupdates (option softdep in /etc/fstab) on your shared filesystems. Although untested, it is likely that SunOS would be confused by a filesystem with soft update flags enabled. The OpenBSD "Sun Compatible" disklabel have been extended to support 16 partitions, however the old SunOS format(8) utility only sees the first 8 partitions and may "lose" information about the extended partitions. Use SunOS format(8) only with *extreme* caution on drives that contain OpenBSD partitions. OpenBSD and Sun BSD bootblocks are similar in concept, though implemented differently. The OpenBSD bootblocks are architecture independent and also understand the extended disklabels with 16 partitions. You can use SunOS bootblocks, but remember that OpenBSD bootblocks must be installed with OpenBSD installboot and SunOS bootblocks with SunOS installboot.