SYLLABUS CODE: 22101/01

O’ LEVEL COMPUTER SCIENCE

Author: Tanvir Iqbal Khan Subject Specialist – O’ Level Computer Science A’ Level Computing

1. PROGRAMMING LANGUAGE It is a set of commands or instructions following grammatical rules for instructing a computer to perform specific tasks. The term programming language usually refers to highlevel languages, such as BASIC, C, C++, COBOL, FORTRAN, Ada, and Pascal. Each language has a unique set of keywords (words that it understands) and a special syntax for organizing program instructions. High-level programming languages, while simple compared to human languages, are more complex than the languages the computer actually understands, called machine languages. Each different type of U has its own unique machine language.

HIGH-LEVEL LANGUAGE The High-level language is a computer programming language which is human oriented alphabetical language and easily understandable. It is not limited by the computer or for one specific job. It is used to write complex computer programs for a specific task. Today, there are dozens of high-level languages; some commonly used high-level languages are BASIC, C, CO OBOL, FORTAN, Java, and Pascal and sometimes assembly language is used.

a. COBOL – Common Business Oriented Language COBOL (Common Business Oriented Language) was the first widely-used high-level programming language for business applications. Many payroll, ing, and other business application programs written in COBOL. COBOL was an effort to make a programming language that was like natural English, easy to write and easier to read the code after you'd written it.

ADVANTAGES OF COBOL   

Simple to implement Requires very low software Efficiency of blocking is good  Blocking results in saving in of input-output time required handling a file.  A substantial amount of storage space on the disk can be saved.

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Updates are not easily accommodated Random access is not possible All records must be structurally identical, if a new field has to be added, and then every record must be rewritten to provide space for the new field. Continuous areas may not be possible because both the primary data file and the transaction file must be looked during merging.

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DISADVANTAGES OF COBOL

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SYLLABUS CODE: 22101/01

O’ LEVEL COMPUTER SCIENCE

Author: Tanvir Iqbal Khan Subject Specialist – O’ Level Computer Science A’ Level Computing

b. FORTRAN – FORmula TRANslator The name FORTRAN is an acronym for FORmula TRANslation, because it was designed to allow easy translation of math formulas into code. Often referred to as a scientific language, FORTRAN was the first high-level language, using the first compiler ever developed. Prior to the development of FORTRAN computer programmers were required to program in machine/assembly code, which was an extremely difficult and time consuming task.

ADVANTAGES OF HIGH-LEVEL LANGUAGE      

It is -friendly and easy to learn because similar to English with vocabulary of words and symbols They require less time to write. They are easier to maintain. Problem oriented rather than 'machine' based. Program written in a high-level language can be translated into many machine language and therefore can run on any computer for which there exists an appropriate translator. It is independent of the machine on which it is used i.e.Programs developed in high level language can be run on any Computer

DISADVANTAGES OF HIGH-LEVEL LANGUAGE

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A high-level language has to be translated into the machine language by a translator and thus a price in computer time is paid. The object code generated by a translator might be inefficient Compared to an equivalent assembly language program

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Website: sirtanviriqbalkhan.tk Facebook: www.facebook.com/tanvirik Email: [email protected]

PHONE: +923212490887

SYLLABUS CODE: 22101/01

O’ LEVEL COMPUTER SCIENCE

Author: Tanvir Iqbal Khan Subject Specialist – O’ Level Computer Science A’ Level Computing

BESPOKE SOFTWARE Bespoke, Tailor made or customized is a type of software which is made to the specifications of a client. In other words it is custom made or 'tailored' to address a specific need of an organization. Usually software packages are bought off-the-shelf. However, certain applications are designed for commercial businesses, industrial companies, etc.), and require specially written software which is unique to that customer and is known as bespoke software.

ADVANTAGES OF BESPOKE SOFTWARE     

Specifically designed for the application and therefore more efficient and will only contain the features wanted. It can be customized to interface with all other software on a computer thus preventing software clashes. Easier to use since very specific and the writers of the software can also be involved in the training of staff which will be geared towards their requirements. can be modified/updated as the company’s requirements change much better customer since they will be in direct with the software designers

DISADVANTAGES OF BESPOKE SOFTWARE

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Very dependent on the suppliers of the software; if they go out of business there will be little or no if problems occur. Less likely to be as well developed/tested as off-the-shelf software. Much more expensive since all the development costs need to be met by the company (but efficiency savings may compensate for this and it may prove to be less expensive in the long run). The development time can be very long which may cause problems. Difficult to tell how good the final software package will be (could be a real problem if the company has waited 2 to 3 years to receive their new software only to find it doesn’t meet their needs.

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Website: sirtanviriqbalkhan.tk Facebook: www.facebook.com/tanvirik Email: [email protected]

PHONE: +923212490887

SYLLABUS CODE: 22101/01

O’ LEVEL COMPUTER SCIENCE

Author: Tanvir Iqbal Khan Subject Specialist – O’ Level Computer Science A’ Level Computing

LOW-LEVEL LANGUAGE Low level language is a machine code binary numbers that a computer can understand directly. The language consists of binary codes (series of 0’s 1’s). A program written in a low-level language can be used only on a computer system that uses one specific type of main processor. Low-level languages are appropriate for writing operating systems, or firmware for micro-controllers. They can do just about anything with a little bit of work. Low-level language is also used to develop virus programs and utility programs.

a. MACHINE CODE Machine code, also called machine language, is a computer language that is directly understandable by a computer's U (central processing unit), and it is the language into which all programs must be converted before they can be run. Each U type has its own machine language, although they are basically fairly similar.

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After the source code for a program has been written by one or more humans in a programming language (e.g., C or C++), it is compiled (i.e., converted) into machine code by a specialized program called a compiler, or by an assembler in the case of assembly language.

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This machine code is then stored as an executable file (i.e., a ready-to-run program) and can be executed (i.e., run) by the operating system any time it is instructed to do so by another program or by a .

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Machine code is extremely difficult for humans to read because it consists merely of patterns of bits (i.e., zeros and ones).

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Website: sirtanviriqbalkhan.tk Facebook: www.facebook.com/tanvirik Email: [email protected]

PHONE: +923212490887

SYLLABUS CODE: 22101/01

O’ LEVEL COMPUTER SCIENCE

Author: Tanvir Iqbal Khan Subject Specialist – O’ Level Computer Science A’ Level Computing

b. ASSEMBLY LANGUAGE A programming language that consists of a group of coded letters or labels, called mnemonics. Mnemonic represents a single instruction that is translated into the binary code of machine language that deals with hardware s by name. Mnemonics are easier to use than machine language instructions. For example, the mnemonic "MUL" tells the computer to "MULtiply".

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Thus, programmers who want to work at the machine code level instead usually use assembly language, which is a human-readable notation for the machine language in which the instructions represented by patterns of zeros and ones are replaced with alphanumeric symbols (called mnemonics) in order to make it easier to and work with them (including reducing the chances of making errors).

Website: sirtanviriqbalkhan.tk Facebook: www.facebook.com/tanvirik Email: [email protected]

PHONE: +923212490887