Fiber Optic cable....

A technology that uses glass (or plastic) threads (fibers) to transmit data. A fiber optic cable consists of a bundle of glass threads, each of which is capable of transmitting messages modulated onto light waves.

A fiber optic cable is a network cable that contains strands of glass fibers inside an insulated casing.

What is Domain Controller?

A domain controller (DC) or network domain controller is a Windows-based computer system that is used for storing user account data in a central database. It is the centrepiece of the Windows Active Directory service that authenticates users, stores user account information and enforces security policy for a Windows domain.

A domain controller allows system administrators to grant or deny users access to system resources, such as printers, documents, folders, network locations, etc., via a single username and password.

What is an operating system?

The Operating System is a software program that controls the processing and hardware associated with a computer. The operating system is the first piece of software loaded into memory when a computer starts. It is the operating system that launches or starts other software programs such as word processors, spreadsheets, databases, etc. The operating system manages all of the resources on the computer; it controls all the hardware in a machine. Manage all programs and resources; handle I/O, security, memory management, storage management, etc are the important functions of an OS.