Terms Letter: O
OC-1, OC-3, OC-12, OC-24, OC-48
Optical Carrier transmission speeds, used in fiber optic networks conforming to SONET standard. OC-1 is 51.85 Mbps. Higher levels are multiples of that speed.
ODBC
Open DataBase Connectivity – A Microsoft standard for accessing different database systems from Windows, for instance Oracle or SQL
Offline
When you are not Online :). In other words when your computer is not connected to the internet.
Online
When your computer is connected to the Internet or a network and communicates with other computers.
Open relay
A SMTP server that allows sending email messages without the need of any kind of authorization. It is a SPAMmers heaven.
Operating system
Sometimes abbreviated as «OS», the program that manages all the other programs in a computer. UNIX, Windows XP, Linux, Free BSD, and MAC OS/X are all examples of operating systems.
OSI
Open Systems Interconnection. The OSI Reference Model is a seven-layer network architecture model of data communication protocols developed by ISO and ITU