FREE online courses on the Basics of a Computer - WHAT IS SOFTWARE - Software software

 

Let us look at the broad categories of system software available. Note that it is making system software that requires in-depth computer expertise, not using it. System software provides us with a number of tools to simplify our life. Of course, as always, there are limitations in every tool, and it is the discretion of the user to decide whether a particular tool is good enough or suitable for the purpose in mind.

 

Operating system is one of the major types of system software. The computer has many resources, and a number of persons vying for them. The operating system acts as the administrator and timekeeper-ensuring fair availability of resources, for purposes of billing. It can usually accept and enforce priorities. It does routine checking of the hardware and reports any problems.

 

For developing application systems, system software provides certain tools. These are the software languages that allow you to talk to the computer. Some require a lot of effort from you; some make your job very simple. Languages that are close to the computer's real language-hence though powerful are also more complicated to use and are called lower lever languages whereas languages which are English-like or where a single phrase can get a lot of work done are called higher-level languages. What system software provides you is the language complete with syntax rules, and the software to convert what is written in that language into a machine-understandable form.

 

Such software that understands what is written in a particular computer language and renders it in the form in which a computer can understand it, is called a compiler or an interpreter. An interpreter reads, interprets and executes the program command by command. A compiler, on the other hand, puts the entire set of commands in a form which can be understood by the machine in a file (sometimes an intermediate step-linking is also needed), and this life can then be executed by a run command. An interpreter is slower in execution, but convenient while writing and testing a program.

 

For all computer languages, the grammar rules are very exact. Unlike natural languages, even a small mistake means the language cannot be understood. The syntax of the language has to be adhered to.

 

Take for example a newspaper you may be reading. It may say something like this -

 

The accused did not admit to the fact that

He had mobbed the cycle from its place.

 

You may notice that there is no word mobbed-and guess that the word actually is moved-it may jar you a little while reading, but you understand nevertheless. But try giving the computer like

 

MOBE A TO B

 

Instead of

 

MOVE A TO B

 

And you will get a plethora of errors. The computer does not understand human error of this sort. It seems silly at times but rules are rules as far as the computer is concerned.

 

To use any language therefore, you have to be familiar with the set of commands it offers as well as the grammar rules or syntax. As elsewhere, mistakes in a written set of instructions could be on two counts. One could be in the construction or grammar and the second in the import of the content - you may have written something which is not quite what you intended to write. The first of these is called a syntax error and second, a semantic error. Whereas a syntax error will halt the compiler and hence be detected and corrected, a semantic error would reflect in program doing something different from what is was supposed to do and will result in a 'bug, also called a 'run-time error.

 

Software provided for forming programs and developing systems is linker software that allows you to bind more than one program together for passing data and parameters from one to another. Besides compilers and linkers, system software also includes system utilities. These all purpose utilities allow a lot of necessary and common activities to be performed. The 'soft' utility for example is used for sorting data on a particular order, such as alphabetic or ascending data order. 'Append' or 'cat' (for concatenate) utility is used for combining data files.

 

Each computer family has its own operating system. So, software written for one system does not run on another. Every new computer introduced then put in action a new set of software requirements - new language compilers, new application packages. However, some standards are now emerging - this is good news because software can now be taken from one machine to another, irrespective of the manufacturer. One such standard operating system is DOS (available as MS DOS and PC DOS), the operating system that is common to microcomputers - the IBM PC family and its numerous clones. For mini computers, the standard emerging all over is UNIX. Although still there are some differences in the UNIX offered by various manufacturers, there is a lot of work going on to make UNIX a uniform standard across the industry for minicomputers.

 

Application software is developed by writing programs in computer languages and then using a compiler to put them in a form that the computer can understand and execute. Each program is a set of instructions aimed at meeting certain requirements. Put together, a set of programs form a system. Hence the word Programmer, one who writes programs. A programr would typically be junior to an analyst, who is the person who analyses the overall system requirements and designs the specifications that each program should meet. The programs to be developed for an application form a system, which is designed after systems analysis.

 

Using the compiler and if necessary the linker with the programs, an executable file is generated, which the machine can understand and run. The program which was written is called the source code.