Programs and programming languages

Computers can deal with different kinds of problems if they are given the
right instructions for what to do. Instructions are first written in one of the
high-level languages, e.g. FORTRAN, COBOL, ALGOL. PL/I, PASCAL,
BASIC, or C, depending on the type of problem* to be solved. A program
s written in one of these languages is often called a source program, and it
cannot be directly processed by the computer until it has been compiled,
which means interpreted into machine code. Usually a single instruction
written in a high-level language, when transformed into machine code,
results in several instructions. Here is a brief description of some of the;

id many high-level languages:

FORTRAN acronym for FORmula TRANslation. This language is used for solving scientific and mathematical problems. It consists of algebraic formulae and English phrases. It was first introduced in the United States in 1954.

15 COBOL acronym for COmmon Business-Oriented Language. This

language is used for commercial purposes. COBOL, which is written using English statements, deals with problems that do not involve a lot of mathematical calculations. It was first introduced in 1 959

ALGOL acronym for ALGOrithmic Language. Originally called IAL, 20 which means International Algebraic Language. It is used for

mathematical and scientific purposes. ALGOL was first introduced in
Europe in 1960. ►

PL/1 Programming Language I. Developed in 1964 to combine

features of COBOL and ALGOL. Consequently, it is used for data processing

25 as well as scientific applications.

BASIC acronym for Beginner's All-purpose Symbolic Instruction Code. Developed in 1965 at Dartmouth College in the United States for use by students who require a simple language to begin programming.

C developed in the 1970s to support the UNIX operating system. C is a

30 highly portable general-purpose language.

Other such languages are APL (developed in 1962). PASCAL (named after Blaise Pascal and developed in 1971), and LISP and PROLOG, both of which are used for work in artificial intelligence. LOGO is a development of LISP which has been used to develop computer-based training (CBT)

35 packages.

When a program written in one of these high-level languages is designed to do a specific type of work such as calculate a company's payroll or calculate the stress factor on a roof, it is called an applications program. Institutions either purchase these programs as packages or commission 40 their own programmers to write them to meet the specifications of the users.

The program produced after the source program has been converted into machine code is referred to as an object program or object module. This is done by a computer program called the compiler, which is unique for each

45 computer. Consequently, a computer needs its own compiler for the

various high-level languages if it is expected to accept programs written in those languages. For example, in order that an IBM RS/6000 may process a program in FORTRAN, it needs to have a compiler that would understand that particular model and the FORTRAN language as well.

50 The compiler is a systems program which may be written in any language, but the computer's operating system is a true systems program which controls the central processing unit (CPU), the input, the output, and the secondary memory devices. Another systems program is the linkage editor, which fetches required systems routines and links them to the

55 object module (the source program in machine code). The resulting program is then called the load module, which is the program directly executable by the computer. Although systems programs are part of the software, they are usually provided by the manufacturer of the machine.

Unlike systems programs, software packages are sold by various vendors 60 and not necessarily by the computer manufacturer. They are a set of programs designed to perform certain applications which conform to the particular specifications of the user. Payroll is an example of such a package which allows the user to input data - hours worked, pay rates, special deductions, names of employees - and get salary calculations as 65 output. These packages are coded in machine language (Os and Is) on magnetic tapes or disks which can be purchased, leased, or rented by users who choose the package that most closely corresponds to their needs. ■

Vocabulary

payroll (1. 62) - list of employees and the amount of money to be paid to each of them

X

Task 3

Task 4

1 2 3 4 5 6

These are answers to questions about the text. Write the questions.

No, it is quite wordy so it is used for commercial purposes.

To support the UNIX operating system.

An applications program.

It is done by the compiler.

It fetches required systems routines and links them to the object module.

No. they are also sold by other vendors.

Summarize the information on different high-level computer languages by completing the table below.

Task 5

Find the passages in the text where the following ideas are expressed. Give the line references.

Systems programs control the work of the computer system. Software packages are not always sold by the manufacturer.

Usually, every high-level instruction translates into many more in machine code.

Systems programs are usually provided by the manufacturer. Programmers may be required to write software for their employers.

Task 6 Using the line reference given, look back in the text and find the reference for

the words in italics.

1 if they are given the right (line 1)

2 it cannot be directly processed (line 5)

3 it is called an applications program (line 38)

4 commission their own programmers (line 40)

5 to write them to meet (line 40)

6 that would understand (line 48)

7 which controls the central (line 51)

8 links them to the object (line 54)

9 They are a set of programs (line 60)
10 which can be purchased (line 66)

Task 7 Using the line references given, refer back to the text and find words or phrases

that have a similar meaning to:

1 converted (lines 5-10)

2 give the responsibility to (lines 3 5-^-40)

3 brings (lines 50-5 5)

4 are compatible with (lines 60-65)

5 matches (lines 6 5-6 7)

Task 8 Choose the correct word to complete each sentence. You may have to change

some words slightly.

1 instruction, instruct, instructed, instructor

a Our maths explained to us the principles of binary

arithmetic.

b We were to document our programs very carefully.

c Both--------------------- and data have to be changed to machine code before

the computer can operate on them.

2 compilation, compiler, compile, compiled

a Our university computer does not have a PASCAL

b Usually, a programmer_____________ his program before he puts in the

data. c A source program cannot be directly processed by the computer until it has

been___________

S

3 result, results, resulting

a The linkage editor links systems routines to the object module. The

------------------- program, referred to as the load module, is directly

executable by the computer.
b The--------------------- of these mathematical operations were obtained from

the university mainframe,and not from my micro.

specification, specify, specific, specified, specifically

a Our company bought three packages with very___________ — applications:

payroll, accounts receivable, and accounts payable.
b An applications program is designed to do a type of work,

such as calculating the stress factor of a roof.
c Did the analyst give the new programmer the--------------------------- necessary to

start on the project?

C language

Listening

Task 9 (Si Listen to this interview with David Wendt, an expert on C. Are the following

sentences true (T) or false (F)?

1 LJ C was written to support the development of the MS/DOS operating system.

C was based directly on a language called BCTL

UNIX was rewritten in C in 1973.

C is rarely used for systems programming now.

C's main disadvantage is that it has a small set of operators.

C is more powerful than Assembler.

C can be used to access memory addresses directly.

Pascal and C produce equally fast and ellicient code.

C is the ideal language for everyone.

A language called D is expected to replace C.

Listen again. Change the sentences that are false to make them true.

Task 10

Не нашли, что искали? Воспользуйтесь поиском: