You can prevent users from accidentally changing or deleting important information on your hard disk by locking files and disks, and adding password protection.
Locking and unlocking files
If a file is locked, you can open it and copy its contents, but you can't change or delete the file. To lock a file, click the name of the file, then open the File menu and choose Get Info.
Protecting files on a disk
You can protect a disk so that the information on it can be viewed but not erased or changed. To protect a hard disk, cartridge, or optical disk, use the Drive Setup application program, inside the Utilities folder on your hard disk.
Note: Many disks and cartridges also have locking mechanisms on their cases or containers. See the instructions that came with the disk for more help.
Password-protecting your portable computer's hard disk
You can protect the contents of your portable computer's hard disk by creating a password. When password security is turned on, you must enter your password when the computer first starts up or when it wakes from sleep (optional).
To create a password and turn on password security, use the Password Security control panel.
You can change your password or turn off password security at any time.
You should not use the Password Security control panel with PowerBook (FireWire) computers. See technical document 60729: "
PowerBook (FireWire): Password Security".