Specifications

Glossary 315
PPD file Postscript Printer Description file. A file that contains information about the
capabilities of a particular printer model. The PPD file provides the controls you need to
take advantage of special features such as multiple paper trays, special paper sizes, or
duplex printing. The printer model you choose when you add a printer specifies the
PPD file used with the printer.
predefined accounts User accounts that are created automatically when you install
Mac OS X. Some group accounts are also predefined.
preferences cache A storage place for computer preferences and preferences for
groups associated with that computer. Cached preferences help you manage local user
accounts on portable computers.
presets Default attributes you specify for accounts you create using Workgroup
Manager. You can use presets only during account creation.
primary domain controller See PDC.
primary group A user’s default group. The file system uses the ID of the primary group
when a user accesses a file he or she doesn’t own.
primary group ID A unique number that identifies a primary group.
print queue An orderly waiting area where print jobs wait until a printer is available.
The print service in Mac OS X Server uses print queues on the server to facilitate
management.
privileges The right to access restricted areas of a system or perform certain tasks
(such as management tasks) in the system.
process A program that has started executing and has a portion of memory allocated
to it.
process ID See PID.
protocol A set of rules that determines how data is sent back and forth between two
applications.
proxy server A server that sits between a client application, such as a web browser,
and a real server. The proxy server intercepts all requests to the real server to see if it
can fulfill the requests itself. If not, it forwards the request to the real server.
public key One of two asymmetric keys used in a PKI security system. The public key is
distributed to other communicating parties. It can encrypt messages that can be
decrypted only by the holder of the corresponding private key, and it can verify the
signature on a message originating from a corresponding private key.
public key certificate See certificate.