Overview of Computer MANDAVI CLASSES PRESENTED BY
Computer is an electronic device that takes input, process it and gives output. Examples are desktop computers, Laptop, Palmtop, Super computer, embedded systems, etc. computer works on 0 and 1 There is no physical significance of 0 and 1 in computer system. 0 and 1 are just representation of two states of voltage levels in digital circuits. If there is a supply of high volt in the circuit it is termed as 1 and for low volt it is 0. These encoding help us to handle any sort of information through digital circuits.
Generation Of Computer Generation in computer terminology is a change in technology a computer is/was being used. Initially, the generation term was used to distinguish between varying hardware technologies. But nowadays, generation includes both hardware and software, which together make up an entire computer system. There are totally five computer generations known till date. Each generation has been discussed in detail along with their time period and characteristics. Here approximate dates against each generations have been mentioned which are normally accepted. Following are the main five generations of computers
S.N.Generation & Description 1 First Generation The period of first generation: Vacuum tube based. 2 Second Generation The period of second generation: Transistor based. 3 Third Generation The period of third generation: Integrated Circuit based. 4 Fourth Generation The period of fourth generation: VLSI microprocessor based. 5 Fifth Generation The period of fifth generation: 1980-onwards. ULSI microprocessor based
Components Of Computers All computers follow a same basic logical structure and perform the following five basic operations for converting raw input data into information useful to their users. Input Unit This unit contains devices with the help of which we enter data into computer. This unit makes link between user and computer. The input devices translate the information into the form understandable by computer. CPU (Central Processing Unit) CPU is considered as the brain of the computer. CPU performs all types of data processing operations. It stores data, intermediate results and instructions(program). It controls the operation of all parts of computer. CPU itself has following three components ALU(Arithmetic Logic Unit) Memory Unit Control Unit
Output Unit Output unit consists of devices with the help of which we get the information from computer. This unit is a link between computer and users. Output devices translate the computer's output into the form understandable by users.
Sr. No. OperationDescription 1Take InputThe process of entering data and instructions into the computer system 2Store DataSaving data and instructions so that they are available for processing as and when required. 3Processing DataPerforming arithmetic, and logical operations on data in order to convert them into useful information. 4Output InformationThe process of producing useful information or results for the user, such as a printed report or visual display. 5Control the workflowDirects the manner and sequence in which all of the above operations are performed.
Computer Software Software is a set of programs, which is designed to perform a well-defined function. A program is a sequence of instructions written to solve a particular problem. There are two types of software 1. System Software 2. Application Software
Hardware is a comprehensive term for all of the physical parts of a computer, as distinguished from the data it contains or operates on, and the software that provides instructions for the hardware to accomplish tasks.
Operating system is essential software which provides an interface between user and machine. It acts as a manager in the system, which manages hardware and software resources. It also does process management, memory management and file management. Examples of Operating systems are windows XP, Windows 2007, Windows 8 Linux, Mac etc.
A computer file is a data bundle created by a program used to refer back to saved work or support the operating of the program. Files are of different types, which mean information is encoded in a particular manner. Each such manner is a separate file format. Notice files stored in your computer’s memory disk, each has some name for identification followed by file extension. File name and extension are separated by a dot operator. File extension tells about type of the file. For example track1.mp3 is a file with extension mp3 which means it is an audio file. Among the several file formats, we are concern about a special file format with extension exe.
It is important to describe the role of few of the hardware resources during execution of program. Earlier we talked about an executable file. Here we are describing execution process of any one of such exe file. Firstly, your program (sum.exe) file is stored somewhere in hard disk of your system. Now we clicked on it to run this program. This click event from mouse is listened by operating system and loads this file from hard disk to RAM (random access memory) using loader (a dedicated program to load content to RAM). Here it is important to note that each time when some program need to be activate, program must load in to RAM. RAM is also known as primary memory which is volatile in nature that is nothing can reside permanently. RAM contains only those programs that are active at particular instant.
Operating system allocates memory for our program in RAM. First instruction goes to the processor and resides in instruction register. This instruction is decoded by control unit. Control unit sends appropriate signal to ALU. ALU performs specific task. Registers, control unit and Arithmetic Logic Unit are part of processor. ALU is responsible to perform all kind of arithmetic, logical and shift instructions. Again next instruction moves to processor and stored at instruction register, control unit decode it and sends a signal to ALU. Every instruction of the program executes in similar fashion in a sequential manner. As soon as the last instruction is executed memory of the program will released from RAM.