Class IX Basics of Operating Systems (Chap 4)

 Class IX Basics of Operating Systems (Chap 4) 

Device Driver A device driver is a group of files that enable one or more hardware devices to communicate with the computer’s operating system. Each hardware device installed on a computer requires a different type of device driver or hardware driver. The device driver provides specific instructions to the operating system in order for the hardware device to perform properly. Types of Operating Systems1. Single User OSIt supports only one user at any point of time. There can be two subcategories of this OS type: 

(i) Single Task OS- This OS supports single application at a time e.g., OS for mobiles, MS-DOS etc. (ii) Single User, Multitasking OS- This OS supports one user but can deal with multiple applications running at a time e.g. simultaneously running word document, a video, internet browsing, listening to music etc. Eg. Windows Vista, Windows 7/8, Linux, MacOS Leopard etc. 

2. Multi program OSIt supports multiprogramming i.e. more than one user can be supported by it, therefore , more than one user programs are loaded and active in the main store at the same time. These active programs are executed using some techniques one by one. E.g. Unix, Linux, IMB AS400 etc. 

3. Time Sharing OSThis OS uses the time sharing technique. Each active user program is given a fair share of CPU time, if the time elapses or and I/O operation is requested, CPU shifts over to the next job waiting and the previous program is put to wait or handed over to I/O manager. The active programs are scheduled for execution using certain job scheduling techniques. Eg. BSD Unix, NOS/VE, Genie etc.

 4. Real Time OSIn real time OS, the jobs have fixed deadlines and the jobs have to be completed within their deadline. The system performance is measured by its ability to complete its jobs within the specified deadlines. E.g. LynxOS, RT, Linux etc.

 5. Multiprocessing OSThe multiprocessing OS is capable of handling more than one processor as the jobs have to be executed on more than one processor. The multiprocessing OS should be capable of load sharing in case of identical processors so that the system’s efficiency improves. In case of unidentical processors, the multiprocessing OS should be able to control the super processor and in turn control the working of slave processors. E.g.- Unix, Linux, Windows NT etc.

1. Multiple choice questions:- 

i. When the computer has to react within a guaranteed time to an input, which type of operating system is best? a. Multi-tasking b. Real time processing c. Batch Processing

 ii. Which type of operating system allows multiple tasks to run at the same time, each taking turns using the resources of the computer? a. Real- time processing b. batch processing c. multi-tasking iii. Which of the following is NOT an operating system? a. Linux b. Windows XP c. Bendix 

2. What are the different types of operating systems? 

Ans2. The operating systems are of mainly following types: i. Single User OS ii. Multiprogram OS iii. Time Sharing OS iv. Real time OS v. Multiprocessing OS

 3. What is Multi-user system? 

 Ans3. A Multi-user system is a computer system designed to be used simultaneously by more than one user. A system that enable more than one user to access the same data at the same time. 

4. Write a short note on Device Driver.

 Ans4. A device driver is a group of files that enable one or more hardware devices to communicate with the computer’s operating system. Each hardware device installed on a computer requires a different type of device driver or hardware driver. The device driver provides specific instructions to the operating system in order for the hardware device to perform properly.

 5. Explain Time Sharing Operating System?

 Ans5. This OS uses the time sharing technique. Each active user program is given a fair share of CPU time, if the time elapses or and I/O operation is requested, CPU shifts over to the next job waiting and the previous program is put to wait or handed over to I/O manager. The active programs are scheduled for execution using certain job scheduling techniques. Eg. BSD Unix, NOS/VE, Genie etc.