Chemistry 1st Paper MCQ Question With Answer

১ম অধ্যায়	ল্যাবরেটরির নিরাপদ ব্যবহার
২য় অধ্যায়	গুনগত রসায়ন
৩য় অধ্যায়	মৌলের পর্যাবৃত্ত ধর্ম ও রাসায়নিক বন্ধন
৪র্থ অধ্যায়	রাসায়নিক পরিবর্তন
৫ম অধ্যায়	কর্মমুখী রসায়ন
	সকল অধ্যায়ের গুরুত্বপুর্ণ তত্বসমুহ

Lesson 5 : Operating System 

5.1. Learning Objectives 

On completion of this lesson you will be able to describe: 

 Operating system and its function 

 Some popular operating systems. 

5.2. Introduction 

Operating system is the software that is responsible for allocating system resources, including memory, processor time, disk space, and peripheral devices such as printers, modems, and the monitor. All application programs use the operating system to gain access to these system resources, as they are needed. The operating system is the first program loaded into the computer as it boots, and it remains in memory at all times thereafter. 

5.3. Some Popular Operating Systems 

Popular PC operating systems include MS-DOS, Microsoft Windows, and Unix. 

5.3.1. MS-D0S 

MS-DOS developed by Microsoft Corporation became the de facto standard for machines designed with Intel processors. IBM selected MS-DOS for its PC’s. This established the popularity of MS-DOS. DOS is helpful to organize disks and use them efficiently, It helps to create and manage files on disks, make copies of them or remove unwanted files from the disks. MS-DOS 5.0 comes equipped with a graphical user interface (GUI) called the DOS Shell. This interface helps the user with everyday tasks such as starting a program or formatting a floppy disk. With the GUI the desired task can be easily selected and started with the mouse by just pointing to the item on the screen and clicking the mouse button. The DOS shell also provides an overview of the contents of the hard disk and floppy disk any time. Several programs can be started at once but only single program runs at a time, the others are suspended.