Operating System Basic Structure
What is an Operating System
The PC or any computer system in general, consist of two main parts. One is the Hardware (which forms the body) and the other part being the Software ( which comprises the mind). For the end user to use the computer effectively, there needs to be an interface between these two sections.
An Operating System or more commonly, the OS is the interface which links the hardware such as Processor, Hard Disc and Memory to the software applications installed in your PC.
Types of Operating Systems
There are different types of operating systems based on their applications.
- Graphical User interface (GUI) : - Modern OS uses GUI concept where icons, button, navigation menu are provided for the user. This is to make the system more user friendly and navigation free. Each OS will have its own customized GUI interface. Eg : Windows, Apple OS X.
- Multi User :- This type of OS allows multiple users to access the same system at same time or different time. Eg; Linux
- Multi Processor - Increased compatibility to use the assistance of more than one computer processor. This reduce the overall work load and increase efficiency. Eg Windows 2000.
- Multi Task :- Allows the computer to run more than one task/process at any given time. Reduces time consumption.
Kernel - The Communication Mode
We know that the OS forms the interface between hardware and software. But how does the communication take place between these two layers.
This is where the Kernel comes in. Kernel is a computer program used to convert the access request of an application program (Software) into instructions, understandable by the computer processor and other input/output devices (Hardware).
The language used for this communication is mainly done in the form of Binary, containing 0s and 1s.
Hardware devices may also come inbuilt with a Firmware which is a read only program. It is stored in the EEPROM and contains the necessary informations to recognize a particular input/output device.
Other functions of the kernel includes.
- Provides assistance to the CPU or processor during multi tasking.
- Memory management services. Allocates memory to computer processes based on their priority level.
Memory allocation is a crucial part of any OS and the correct utilization can help increase overall system performance and efficiency.
Memory management services keeps track of each processes running within the OS and allocation part of the memory as blocks, for the same.
The various methods by which this is achieved is as follows.
- Dynamic Loading :- Here routines/tasks are loaded into memory, only when called by the main program. The main program is initially loaded and then according to request issued, the routine, methods and modules gets transferred.
- Dynamic Linking : - Here various modules and codes of data are collected, combined together to form a single executable file. This file is then loaded into memory and processed.
- Swapping :- Swapping is a procedure by which a process is temporarily taken out of the main memory and then placed in a secondary one. The criteria for the secondary memory is that it should have large memory space and also be easily accessible. Major time consumption is during the data transfer time. The total time is directly proportional to them amount of data swapped.
Security Options in an OS
There are number of unethical people who would like to take control of your computer and cause wide havoc. The usual threat attacks they employ, include
- Trojan Horse :- Named after the mythical horse of Troy, this malware disguises itself as a legitimate and useful program. Once installed, a back door will be created by which a third person (commonly known as a Hacker) can take control of your PC.
- Worm :- Highly dangerous, worm infection can cause file corruption in the PC and also reduce overall speed of your net connection.
- Virus :- Attacks and corrupts core system files. Reducing performance, virus are capable of self replicating, once installed into the computer.
- Adware : - This malware opens or pops up unwanted ads in your internet browser. In some cases, the home page is also changed and directed to another third party site.
To counter these attacks, there are certain security options provided by the Operating System. They include
- Username/Password login : - The first line of defense, each user of a computer is provided with a unique username and password. The system settings, GUI interface, are custom made for each user.
- Firewall :- Present in the Security Option in the Control Panel tab, this application monitors the network traffic that pass through your PC ,when it is online. It is strongly recommended not to turn off the firewall in any case.
- Biometric identification / Fingerprint Scanning : - Mostly seen in laptops, net books, an additional security feature which user need to provide, to access the system..
- Anti Spyware software :- New versions of Windows Operating Systems has inbuilt Anti Spyware softwares such as Windows Defender which provide protection against malware attacks.
- Kernel (computing) - Wikipedia, the free encyclopedia
- HowStuffWorks "Memory Storage and Management"
A computer's memory storage and management is also handled by the operating system. Learn about the types of memory storage and management.
- Operating System Tutorial
Operating System Tutorial for Beginners - Learning operating system concepts in simple and easy steps : A beginner's tutorial containing complete knowledge about an operating system starting from its Definition, Functions, Conceptual View, Program Ex