An operating system (often called OS or O/S) is like a middleman between your computer’s hardware and the software you want to run. Every computer needs an OS to get anything else done. Operating systems handle the basics, like figuring out what you’re typing on the keyboard, showing stuff on the screen, keeping tabs on files and folders, and managing gadgets like disk drives and printers.

Compiler:

A computer is a special program that processes statements written in a particular programming language and turns them into machine language or “code” that a computer’s processor uses.

Interpreter:

The interpreter is normally a program translator used for translating computer language into machine language and immediately executes it. The following figure is shown to explain the related hardware, software, and user of the computer system.

The important factor is language which requires communicating with a computer. Some of the basic natural languages we are familiar with are English, Hindi, Oriya, etc, but the computer will not understand any of these languages. But how will you communicate with your computer? So, let us discuss about the computer language.

What is Language?

The computer will not understand the user’s language when transferring data and instructions. So there are programming languages specially developed so that you can pass your data and instructions to the computer to do specific jobs e.g. FORTRAN, BASIC, etc.

Programming Language:

There are two major types of programming languages. These are low-level languages and high-level languages.

Low-Level Language:

The term low level means closeness to the way in which the machine has been built. Low-level languages are machine-oriented. They cannot easily be converted to turn on a computer with a different central processing unit, and they are relatively difficult to learn because knowledge of the internal workings of the computer is required. Since they must be translated into machine code by an assembler program, low-level languages are also called assemble language. E.g FORTRAN, BASIC, COBOL, etc.

Machine Language:

Machine Language is the only language that is understood by the computer. It does not need any translation program. We also call it machine code and it is written as a string of 1’s (one) and 0’s (zero). When this sequence of codes is fed to the computer, it recognizes the codes and converts them into electrical signals needed to run it. It is considered to be the First-generation language. It is also difficult to debug the program written in this language.

Advantages:

The only advantage is that the program of machine language runs very fast because no translation program is required for the CPU.

Disadvantages:

1. It is very difficult to program in machine language.
2. The programmer has to remember a lot of codes to write a program.

Assembly Language:

It is the first step to improve the programming structure where the set of symbols and letters forms the Assembly Language and a translator program is required to translate the Assembly Language to Machine Language. This translator program is called ‘Assemble’. It is considered to be a second-generation language.

Advantages:

1. The symbolic programming of Assembly Language is easier to understand and saves a lot of time and effort for the programmer.
2. It is easier to correct errors and modify program instructions.
3. Assembly Language has the same efficiency of execution as the machine-level language.

Disadvantages:

1. One of the major disadvantages is that assembly language is machine-dependent. A Program written for one computer might not run on other computers with different hardware configurations.

High-Level Language:

Higher Leven Language are simple languages that use English and mathematical symbols like +,-,%,/ etc. For its program construction. Higher-level languages are problem-oriented languages because the instructions are suitable for solving a particular program.

Programming languages such as C, FORTRAN, or Pascal use programmers to write programs that are more or less independent of a particular type of computer. Such languages are considered high-level because they are closer to human languages and further from machine languages.

Advantages:

Higher-level languages have a major advantage over machine and assembly languages and higher-level languages are easy to learn and use. It is because they are similar to the languages used by us in our day-to-day life.

Data Communication:

Data communication technologies deal with means and methods of data transfer from one location to another. So, it is necessary to understand the technologies used for computer networking.

About Computer Network:

In a computer network, two or more computers are linked together with a medium and data communication devices to communicate data and share resources. The computer that provides resources to other computers on a network is known as a server. In the network, the individual computers, that access shared network resources, are known as workstations or nodes.

Computer Networks may be classified based on geographical area into three categories.

1. Local Area Network(LAN)
2. Wide Area Network(WAN)
3. Metropolitan Area Network(MAN)

Local Area network:

LAN is used to interconnect computers in a single room, rooms within a building, or buildings on one site are called Local Area Networks (LAN). LAN transmits data at a speed of several megabits per second(106 bits per second). The transmission medium is normally coaxial, fibra, or twisted cables.

Advantages:

• The reliability of the network is high because the failure of one computer in the network does not affect the functioning of other computers.
• The addition of a new computer to the network is easy.
• A high rate of data transmission is possible.
• Peripheral devices like magnetic disks and printers can be shared by other computers.

Wide Area Network(WAN):

The term Wide Area Network(WAN) is used to describe a computer network spanning a regional, national or global area. For example, for a large company, the head-quarters might be in Delhi, and regional branches at Bombay, Madras, Bangalore, and Kolkata. Here regional centers are connected to headquarters through WAN. The distance between computers connected to WAN is larger. Therefore the transmission medium used is normally telephone lines, microwaves, and satellite links.

Advantages:

• Communication Facility: For a big company spanning different parts of the country the employee can save long distances on phone calls and it overcomes the time lag in overseas communication. Computer conferencing is another use of WAN where users communicate with each other through their computer systems.
• Remote Data Entry: Remote data entry is possible in WAN. It means sitting at any location you can enter data, update data, and query other information of any computer attached to the WAN but located in Delhi, you can do it through WAN.
• Centralized Information: In a modern computerized environment you will find that big organizations go for centralized data storage. This means if the organization is spread over many cities, it keeps its important business data in a signal place.

Metropolitan Area Network(MAN):

A MAN is optimized for a larger geographical area than a LAN, ranging from several blocks of buildings to entire cities. MANs might also be owned and operated as public utilities. They will often provide means for internetworking of local networks. The metropolitan area network can span up to 50 km, devices used are modern, and wire/cable.