.rc files

Dot files are configuration files that perform such functions as creating aliases for shell commands, setting environment variables, geometry of X applications etc.Their file names start with a dot (.).
These files are simple text files and can be created or modified with any Unix text editor.

The .rc files are script files containing program. They are usually text files containing commands that are to be executed automatically each time the system starts up.

See Also >> .profile files

.profile files

Dot files are configuration files that perform such functions as creating aliases for shell commands, setting environment variables, geometry of X applications etc.Their file names start with a dot (.).
These files are simple text files and can be created or modified with any Unix text editor.
The .profile file sets up a default working environment.
The commands stored in the .profile file are called environment variables, since they establish a working environment.
Your working environment is determined by the content of .profile and .rc files
For example, the following line sets the PATH environment variable, which indicates the directories where the shell needs to search for programs that you might execute:

export PATH=/bin:/usr/bin:/usr/local/bin:/usr/openwin/bin


See Also >>  .rc files

What is Word

A word is the computer's internal storage unit and refers to the amount of data it can hold in its registers and process as a single unit. For example, a 16-bit computer processes two bytes in the same time it takes an 8-bit computer to process one byte, providing the timing clocks are of equal speed. 

What is WORM

WORM stands for Write Once Read Many. A storage disk that is more easily written than CD-ROM, making single copy disks commercially feasible.

What is word length

A measure of the size of a word, usually specified in units such as characters or bits. Each location of a computer system can store a fixed number of characters or bits called its word length.

What is Wafer

A wafer is a round slice of a silicon approximately 1/30th of an inch thick and form three to six inches in diameter that is the base unit upon which hundreds of chips are created through a series of photo-masking, etching and implementation steps.

What is Volatile Memory

A memory in which a constant electrical power source is required to maintain the contents of memory. If the power is switched off, the stored information is lost.

What is VLSI

VLSI stands for Very Large Scale Integration. An electronic circuit with about 10,000 transistors fabricated in a single silicon chip.

What is Virus

A virus is a program that is used to infect the operation of a computer system.

What is Virtual System

An extension of virtual storage concept. With virtual systems, users can share all of the computer resources as if each user hard his own computer.

What is Virtual Memory

The technique of using disk space to make programs believe that the system contains more random access memory (RAM) than is actually available. This can be implemented by using pure segmentation, pure paging, or a combination of both.

What is Video Display Unit (VDU)

An I/O device that consists of a television-like screen for displaying outputs and a keyboard for entering inputs.

What is USRT

USRT stands for Universal Synchronous Receiver Transmitter. A USRT is an electronic circuit that converts parallel bits to serial bits and vice versa. Inside the computer, data is worked on in parallel (8 or more bits at a time), whereas transmission over a communications channel is serial (one bit following the other). The USRT is also responsible for generating timing for synchronous transmission.

Who is User

Any individual who supplies input data to, or uses information generated by a computer based system.

What is Unix

A popular operating system for 16-bit mini and micro computers that was designed by Bell Telephone Laboratories, USA.

What is UNIVAC

An acronym for Universal Automatic Computer. It was the first commercially available computer.

What is Unconditional Jump

A jump that takes place whenever the instruction that specified it is executed.

What is UART

UART stands for Universal Asynchronous Receiver Transmitter. A UART is an electronic circuit that converts parallel bits to serial bits and vice versa. Inside the computer, data is worked on in parallel (8 or more bits at a time), whereas transmission over a communications channel is usually serial (one bit following the other). The serial transmission is asynchronous, which means the UART is responsible for generating and detecting the start and stop bits that accompany each character transmitted.

What is Two's Complement Representation

Used to represent binary numbers. A positive number is represented as in sign-magnitude. A negative number is represented by adding one of the one's complement representation of the same number.

What is Truth Table

A truth table defines all the input and outputs of a logical condition. The following example is a truth table for the Boolean AND operation -
 Inputs Outputs
------------ --------------
1 AND 1   1
1 AND 0   0
0 AND 1   0
0 AND 0   0