Analog computerThe computer which can process analog quantities (continuous data) is called an analog computer. They are designed to accept physical quantities such as temperature, pressure, speedometer, etc and record them as readings along a continuous scale.
Features of analog computer:- These computers work on the derived quantities as temperature, speed, voltage, etc.
Digital computerThe computer which accepts discrete data (discontinuous data) is known as digital computer. The digital computers operate by counting numbers, or in other words, it represents information in discrete form. It operates directly on numbers expressed in binary number system. Digital computers are more accurate than analog computer, since there is no analogous representation.
Features of digital computers- These computers only operate on digit and they are 0 & 1.
Type of SoftwareSystem software/ Application software
System SoftwareIt is a collection of program, language, etc which allows the user to communicate with computer equipments, the software makes the machine easier to use and make efficient use of resources of hardware. It is like a layer which acts as interface between computer and application software. It is used in almost all kinds of computer like mainframe, mini or micro computer.
Types of system softwareOperating system/ Translating Program/ System support software/ utility software
Application softwareApplication software is prepared and supplied by software company and computer manufacturer. Application software is a subclass of computer software that employs the capabilities of computer directly to a task that user wishes to perform. Application software are designed to process data and support users in an organization such as solving equations or producing bills, result processing of Pokhara university, etc.
Types of application softwareTailored package/ Packaged software
Tailored packageTailored software is the software, which are specially designed and developed to solve a specific or particular task. The nature of processing of data seems similar but actually they are different in many ways. High-level language such as COBOL, BASIC, FORTRAN, PASCAL, C, etc. is used to prepare tailored software. Examples: salary sheet, sales ledger, payroll system, library management, etc.
Packaged softwarePackaged software is the software which is generalized a set of programs and developed for general purpose. These programs are user friendly and designed for use in more than one environment. Examples: Word processing packages: MS- Word, MS-Star etc. Spreadsheet: Excel, Lotus, etc. Graphics: Photoshop, 3D studio max, etc. DBMS Package: Dbase III, Oracle, etc.
Machine Level Languages (MLL) :-Computers are made of No. of electronic components and they all are two – state electronic components means they understand only the 0 – (pulse) and 1 (non – pulse). Therefore the instruction given to the computer must be written using binary numbers. 1and 0. Computers do not understand English or any other language but they only understand or respond to binary numbers(0 and 1). So each computer has its own Machine languages.
Advantages:1. Time taken to execute program is less.
Disadvantages:1. Difficult to learn.
Assembly Level Languages (ALL) :-In assembly language instruction are given in English like words ,such as MOV,ADD,SOB etc. Hence it is easy to write and understood assembly language. As we know computer can understand only machine level language . Hence assembly language program must be translated into machine level language. The translator which is used for translating is called “assembler”.
Advantages:1. Assembly language is easier to understand as compared to machine language.
Disadvantages:1. It is machine dependent.
High level language:-It is designed keeping in mind the features of portability means these language are machine independent. These are the English like language, so it is easy to write and understand the programs of high level language. For translating high level language program into machine language we used “compiler” and “Interpreter” are used. The language in this category is:- FORTAN,COBOL,C,C++,etc.
Advantages:1. They are easier to learn as compared to assembly and machine language.
Disadvantage:1. Require more time and memory to execute.
Type of TranslatorAssembler/ Compiler/ Interpreter
AssemblerIt is used for converting the code of assembly language into machine level language. This translation is done with the help of a translator program called assembler. Assembler is a system software supplied by computer manufacturers.
CompilerIt is used for converting the code of high level language into machine level. The compiler searches all the errors of program and lists them. A Compiler checks the entire program written by user and if it is free from error and mistakes then produces a complete program in Machine language known as object program.
InterpreterThe work of interpreter is same as compiler. It is also used for converting high level language program into machine level language but it checks the errors of program statement by statement .
Error finding:Error finding is much easier in Interpreter because it checks and executes each statement at a time. So wherever it fine some error it will stop the execution. Where Compiler first checks all the statement for error and provide lists of all the errors in the program.
Time:Interpreter takes more time for the execution of a program compared to Compilers because it translates and executes each statement one by one. Examples: C, C++, FORTRAN, etc are compiler whereas BASIC, LISP, etc are interpreter.