Running and Testing the Computer Program

The operating system is a collection of programs provided by the computer's manufacturer that allows us to schedule jobs for the computer, to translate source programs into object programs, to sort data stored on secondary storage devices, and to copy data from any input device to any output device. These programs are called control programs, language programs and utility programs.

The control program (often called the supervisor, monitor, or executive) is a main-storage-resident program. Its functions are to schedule jobs, schedule input and output for our programs and to monitor the execution of our programs.

The language processors are programs that translate source programs into object programs. There are three types of language processors: assemblers, compilers, and interpreters. Each language has its own language processor.

The service programs are programs that are commonly used in all data processing centers. They have functions that are required by everyone using a computer. Examples of service programs include linkage editors to prepare object programs for execution, a librarian to catalog programs into a library area on magnetic disc, utility programs to transfer data from device to device, and sort ­merge programs for sorting data on magnetic tape or disk.

As for testing of the computer program, there are two kinds of errors or bugs with which programmers must deal. The first type is the coding error. Such errors are syntax errors that prevent the language processor from successfully translating the source program to object program code. The language processor identifies the nature and the location of the error on the source program listing, so these errors are relatively easy to find and correct. The second type of bug is the logic error. The computer program can be successfully translated, but the program does not produce the desired results. These errors are generally much more difficult to find and to correct than are coding errors. Logic errors can be avoided through careful planning of the program logic, but it is the programmer's responsibility to test thoroughly all of the program's functions, in order to verify that the program performs according to specifications.

There are many tools provided to the programmer to help in debugging the program logic. These tools are called debug packages or tracing routines. They assist the programmer in following the logic by printing out calculation results and field values used in making logic decisions in the program. In a few cases it may be necessary to use a memory dump - a printout of the instructions and date held in the computer's memory - in order to find the cause of logic errors.

Vocabulary Notes

a manufacturer ["mxnju'fxktS(q)rq] – фабрикант, підприємець, виробник

to schedule ['SedjHl] jobs – назначати (планувати роботу)

an utility [ju(:)'tIlItI] program – програма, яка обслуговує

a source program – початкова програма

an object program – кінцева (об’єктна) програма

an assembler [q'semblq] – асемблер (програма, яка транслює програму на мові асемблера в машинний код)

a compiler [kqm'paIlq] – компілятор, компілярна програма

an interpreter [in'tWprItq] – інтерпретатор, тлумач

bug [bAg] – n. вірус; v. встановлювати таємно апаратуру для підслуховування

an error – помилка

a desired result – бажаний результат

to avoid – запобігти, анулювати

responsibility – відповідальність

thoroughly ['TArqlI] – ретельно, досконало

to verify ['verIfaI]– перевіряти, контролювати, підтверджувати

to debug – настроювати (машину, програму), анулювати неполадки

a printout – роздруківка, вивід даних через друкарський пристрій

a debug package – пакет програм, який відповідає за несправності

sort/merge program – програма (зовнішнього) сортування методом розбиття/злиття

to monitor – контролювати, перевіряти якість програми; спостерігати, слідкувати

an editor – редактор, програма редактування

specifications ["spesqfI'keISns] – технічні умови