high-level language & low-level language-2

8/10/2019 High-Level Language & Low-Level Language-2

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SYLLABUS CODE: 22101/01

O’ LEVEL COMPUTER SCIENCE

Author : Tanvir Iqbal KhSubject Specialist – O’ Level Computer Scie

A’ Level Compu

Website: sirtanviriqbalkhan

Facebook : www.facebook.com/tanvi

Email : [email protected]

PHONE: +92321249088

1.

PROGRAMMING LANGUAGEIt 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 high-level 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 CPU has its own unique machine language.

HIGH-LEVEL LANGUAGEThe 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, accounting, 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 support

Efficiency of blocking is good

Blocking results in saving in terms of input-output time required handling a file.

A substantial amount of storage space on the disk can be saved.

DISADVANTAGES OF COBOL 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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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 User-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

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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A’ Level Compu




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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 support since they will be in direct contact with the software designers

DISADVANTAGES OF BESPOKE SOFTWARE

Very dependent on the suppliers of the software; if they go out of business there will be little or no

support 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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A’ Level Compu




PHONE: +92321249088

LOW-LEVEL LANGUAGELow 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 CPU (central processing unit), and it is the language into which all programs must

be converted before they can be run.

o

Each CPU type has its own machine language, although they are basically fairly similar.

o

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.

o

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 user.

o

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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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 registers by name.

Mnemonics are easier to use than machine language instructions. For example, the mnemonic

"MUL" tells the computer to "MULtiply".

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 remember and work with them (including reducing the

chances of making errors).

high-level language & low-level language-2

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