You press the 6 and 4 keys while booting. There seems to be no point in doing so though since all apps that are 64 bit will still run in 64 bit mode even if you don't (just check the activity monitor). The only difference is that it loads the 64 bit kernel and kernel extensions.
I recently added two new HDD to my PC (ububtu 9.04). I'm going to use the first one for backup and I want the backup script to mount/unmout it.
The problem is that this fails
mount /dev/sdc1 /mnt/myBackup
... it just results in
I added this to fstab and rebooted but it does not help
/dev/sdc1 /mnt/myBackup ext3 user,noauto 0 0
I want the second HDD to automatically mount at "/home/<user>/Virtualbox". I tried adding