Operating System : What is an Operating System

What is Operating System?

An Operating System is software made of data and programs that has a control to execute the application programs. It acts as an interface between hardware and applications. The layer of a computer system is shown below.

Simple Diagram showing various layers of operating system bewteen hardware and user

Fig. 1: Simple Diagram Showing Various Layers Of Operating System Between Hardware And User

An operating system abandons the control functions of a processor. Operating systems are present in the electronic devices such as video game console, web servers, supercomputers, cellular phones and many more.

The three functions performed by the Operating System are:

· Efficiency – The resources of the computer system can be used efficiently.

· Convenience – The computer can be used conveniently, without any hassles.

· Ability to evolve – It allows to develop, test, and introduce new system functions with no interference of the service.

Purpose of an Operating System

The two main purposes to develop on an Operating System are:

· An Operating system can have power over the usage and allocation of the various computer resources.

· An Operating system serves as an interface between the programmer and computer hardware. This makes it easy for coding, creating and debugging of the programs required for applications.

Tasks supported by an Operating System

The Operating System must maintain the tasks such as:

· Create and modify the program and data file with help of an editor.

· Compiler must be accessible in order to decipher the user programs from high level language to machine language.

· Offer a loader program to shift the compiled program to the memory of the computer for further executions.

· Offer routines to manage the details of I/O programming.

Operating system Services

Program Execution – Program is loaded into memory and then executed. The execution must be ended normally or abnormally.

I/O operation – I/O refers to any file or I/O device. The operating system must offer any I/O device to run a program.

File system manipulation – Program has to either write or read a file. The program can operate on the file as the permission is granted by the operating system.

Communication – Some time is required for the data to be transferred between two processes. Both processes are either on a single computer or on two different computers which is connected through a computer network. There are two methods for communication – shared memory and memory passing.

Error detection – An error can arise in I/O device, CPU, or in the memory hardware. The operating system should be alert regarding the errors that occur and must take apt act for correction.

Kernel

Kernel is a part of the operating system which is present in the memory. Kernel is also known as the nucleus of the operating system. This part of the operating system contains the functions that are frequently used.

Types of Operating System

There are three types of operating system.

1. Batch Processing – Input data along with Jobs are fed as a batch into the system. After the first Job is completed, the Second Job can begin to execute. Unless the previous job is completely executed, the next Job has to wait.

2. Real time processing – This method looks out for immediate response. Example, aeroplane landing control system, interrupt error in computer system, anti-missile defence system.

3. Time Sharing processing – Time slots are allotted to each user to interact with the system. The system decides the size of the time slot.

History

During the year 1950, the computer could carry out operation for only a single program at a time. The machine would be loaded with the program and the machine would be operated only after the program was completely loaded. Debugging of a program could be carried out using toggle switches and panel lights on the front panel. Alan Turing was known to be the master of Manchester Mark 1 machine. From the principles of the Universal Turing machine, Alan Turing derived the primitive conception of an operating system.

Soon after machines came with loads of software that were linked to the user’s programs to perform various operations which include input and output and create computer code from the human readable symbolic code. Still machines could execute only a one program at a time. This is called as the serial system.

Before the processing starts, the programs and data are collected in a batch which is called as batch operating system. The data and programs collectively form a single unit called as job.

Fig. 2: Memory Layout Diagram Of A Simple Batch In Operating System

The memory layout of a simple batch system is categorized into two parts, Operating System and User space. Jobs are processed on the basis of first come first. The memory is released after the execution of the job is done. The output is copied to an output spool for printing. Batch system offers various simple forms to manage the file.

Spooling is an acronym for simultaneous peripheral operations on line. At rural sides, spooling is used for data processing. The common application of spooling is print spooling.

The table given below explains the history of Operating System in detail.

Generation	Year	Electronic devices used	Types of OS and devices
First	1945-55	Vacuum tubes	Plug boards
Second	1955-65	Transistors	Batch systems
Third	1965-80	Integrated circuit	Multiprogramming
Fourth	Since 1980	Large scale integration	PC

Comparison of various OS

Special features of an Operating System

1. Multi tasking – It can manage to execute two or more programs to execute at the same time. Actually, the CPU can handle only one task at a time. Since the execution is carried on fast, it appears as though 2 or more jobs execute at the same time.

2. Multiprogramming – At the same time, 2 or more programs are saved in the main memory.

3. Parallel Processing – It can execute the jobs by making use of 2 or more CPU’s.

4. Buffering – They are temporary storage regions. The data is read from an input device and transfer the data to the output device. Since the I/O operation is slow, the CPU is always busy.

5. Spooling – They are larger buffers from the hard disk which stores data through I/O operation.

Operating System Comparison

The most popular and widely used operating systems include Microsoft Windows, Mac OS X, and Linux.

Fig. 3: Image Showing Logos Of Some Popular Operating Systems Microsoft Windows, Mac OS X, And Linux

· Microsoft Windows: Windows is the most popular operating system in the world today. Ever since the launch of Windows 1.0, the world has seen significant developments with Microsoft’s releases over the years: Windows 95, Windows 2000, Windows XP, Windows Vista and finally, Windows 7. Today, Windows has evolved into a platform that is very user-friendly and compatible with most software and hardware.

Windows is more expensive than other operating systems because it is proprietary software. Windows is frequently attacked by hackers and it is important to protect your system with anti-virus software.

· Mac OS: Apple had introduced Mac OS X operating systems for its range of Macintosh computers. The Mac OS X is based partly on the UNIX platform and has very similar administrative controls. Mac OS X software requires minimal maintenance and is resistant to viruses, malware and spyware. The only disadvantage associated with Mac OS X is its inability to be compatible with most software and hardware. Mac OS was first supplied along with Macintosh systems in the year 2002. Note that this operating system was first introduced in the year 1984. Currently, all Mac OS versions are depicted in Roman numerals. The latest version is Mac OS X.

· Linux: The Linux operating system is based on UNIX and is regarded as a very secure platform. Since Linux is an open-source project, it allows users to freely access the source code. Linux requires relatively lesser hardware than other operating systems, and therefore, provides high performance even on a smaller hard disk. A huge community of users regularly contributes codes to improve functionality and performance of Linux. Since Linux is server-based, it has fewer home-based users. Linux only provides limited multimedia support. Red Hat, Mandrake, Suse, and Fedora are the most popular Linux operating systems. Linus Torvalds, the creator of Linux, first began work on this operating system in 1991. Today, Linux is among the most popular operating systems in the world.

Future

We often face problems when we install new hardware’s or software’s into our system. To solve this issue, new wizards are implemented which can guide us by giving step by step instructions to perform a function. In future, wizards will be integrated into the operating systems to carry out functions like cleaning the system automatically, deleting unwanted files, etc.

We encounter technical problems when we transfer file between two platforms. In future, this problem will solved and operating system can translate into a configuration supported by a native platform automatically.

Active desktop helps to search hard drives and surf the Net. In future, the HTML with Active X Controls and Java will be the File standards on applications and on the desktop. The graphical User interface will be replaced with the Network User Interface. Without a separate web browser, you can access the web directly from the Operating System.