What do you understand by scope of a variable ?


Scope of a variable means availability of a variable. The variable can be accessed only within the function where it is declared. Global variables are accessible within all functions. A variable defined within a function is not visible in other functions. If local variable and global variable have same name, then within the function, if the name is used, then the value of local variable is accessed. That is local variable overrides the global variable.

What is Device Driver?


Device drivers are programs which when executed by CPU result in operation of an equipment. For example a printer driver is executed when print command is given. This program when executed result in generation of proper data for printer operation and for initializing printer controller and associated circuits.

What is Protocol? What is IP Protocol?


A Protocol is a set of rules that is to be followed between two communicating parties so that communication between them can take place smoothly.

IP is the standard Internet Protocol. It is the protocol used for communication over Internet.

What is flip-flop?


Flip flop is a one bit memory. It is a circuit that is used to store one bit. Flip flop is the basic building block in sequential circuit. It is used to store the state of sequential circuit so that the next state will be based on the current state of the circuit. They are used in counters, shift registers, sequence generators etc.

What do you understand by booting of a computer? What are the main activities that are carried out by a computer during booting?


Booting in modern PC refers to the initial set of process that PC does when it is powered ON. When power is turned ON, control is transferred automatically to address FFFFO by hardware. This location is in ROM and contains a jump to boot strap procedure in the BIOS ROM. The boot strap procedure carries out some hardware tests and if the machine passes the test, it tries to read the boot sector from diskette A. If no diskette is present in drive A, the primary boot sector of hard disk is read in. The primary table in primary boot sector tells the where the partition are and which one is active. The active partition is read and then executed. The boot sector reads its own root directory to see if io.sys and msdos.sys are present. If so it reads then both into memory and transfers control to io.sys. Once loaded io.sys calls BIOS procedures to initialise the hardware. Then sysinit program is executed and reads config.sys to configure the system.