Hardware is device that are connected to form a computer system. It is physical equipment of computer system. Devices are connected together to form an effective working system for any purpose solving. Hardware are
1. Input device
2. Storage device
3. Processing device
4. Output devices
These are devices that are used to take input from outside world to computer system for processing. Example keyboard, mouse, scanner.
These are devices to store any data , intermediate data and final data for future processing or presenting output. Example Hard-Disk, magnetic tape, compact disk.
These are devices that are used for processing the data. Example is CPU.
These are devices used to present the processed output to outside world. Example printer, projector.
Software is sequence of operations or instructions that computer has to perform. Computer can not do anything on its own but we must be instructed to do some specific task. Software's are written in some specific language that can be understood by a computer system they are called computer program.
Programs or software's are of two types
1. Application programs ( application software).
2. System programs ( system software).
These are programs that are formed by 1 or more programs that are designed to perform some specific kind of activity.
Example. Database management, word processing, billing system, etc.
These are also program that are formed by 1 or more programs to manage the operation of computer system like managing files, controlling backup, running application.
How the programs works
Programs stored in computer storage or main memory. Operator issues command and program gets loaded and ready to execute. The program tells the computer what to do and in which order is to be executed. The computer reads the program line by line and decodes its instruction, translates them into digital signals. Digital signals are formed by 0s and 1s. This process is controlled by CPU. CPU keeps watch on these instructions.
Computer system are channel for communication or system of communication it is just like we (people) communicate by using languages like English, Hindi etc. Programs write their program in computer programing language to inform or to instruct computer to perform task.
Programing languages are of two categories
1. Low level programming language.
a. Machine languages.
b. Assembly languages.
2. High level programming languages.
a. Third generation languages(3GL).
b. Fourth generation languages(4GL).
c. Object oriented programming(OOP).
Low level languages
Low level languages are designed for particular computer according to its internal code. It is not used by other computer with different CPU because it is computer specific. Low level programming language is translated to machine code by assembler.
It is language which is understood by the computer without using translating it into computer understandable form. This language is called machine language or machine code of the computer. It is basics of computer that consist of binary digits that are 0s and 1s. It is lower level of languages. It runs on specific computer on which it is prepared or designed.
Machine language is not easy to understand or to develop(write) so to overcome this new languages are designed this is called assembly languages. It is the language that substituted letter corresponding to symbols. Programers use meaningful words, abbreviation for program instead of remembering sequence of binary digits. Advantage of assembly is that programer can identify the memory location by some symbols instead of actual numeric storage. One of the disadvantage of assembly languages is it is need to be converted to machine language which is understandable by machine to execute that task.
High level languages.
These are advanced Languages. These languages enable the programers to write instructions using English words and most common mathematical symbols such as plus(+), minus(-) etc. In this high level instruction are converted into machine understandable code by compiler as well as by interpreter.
Third generation language(3GL).
It is set of English words. Example PRINT for print,SUB for subtract etc. Many other language also supports symbols for addition or subtraction such as "+" for addition and "*" for multiplication etc.
Example of 3GL
COBOL, FORTRAN, ALGOL, BASIC.
Fourth generation language(4GL)
In fourth generation languages we uses English like statements. In 4GL we specify whats the output without specifying how to get that output. It is faster than other languages. It requires less time and programmers effort.
Example of 4GL
SQL (structural query language) used for query in database.
OOP is event driven programming. In this objects are created which reflect real-world entity in computer system. It is termed as OOP. Example C++, JAVA, C#.
Difference between Compiling and translation
1. Interpreting is kind of translation in which the programs are translated into machine language while the program is carried out but compiling process translates the entire program into machine language before the program is executed.
2. Interpreter program reads the program line by line and translate it into machine language to which is to execute but compiler compiles entire programs at ones.
3. Interpreting is slow in process but compiling is faster process.