Computer Studies - Junior Secondary 3 - Disk Operating System

Term: 3^rd Term

Week: 2

Class: Junior Secondary School 3

Age: 14 years

Duration: 40 minutes of 2 periods each

Date:

Subject:      Computer studies

Topic:-       Disk Operating System

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

1. Explain disk operating system
2. Describe how a disk operating system works

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

NOTE

DISK OPERATING SYSTEM

A DOS, or disk operating system, is an operating system that runs from a disk drive. The term can also refer to a particular family of disk operating systems, most commonly MS-DOS, an acronym for Microsoft DOS.

An operating system (OS) is the software that controls a computer's hardware and peripheral devices and allows other software programs to function. Early computers of the 1940s and 1950s did not have disk drives. Instead, they were hard-wired to carry out specific computations.

Later, computers were able to store instructions loaded into the computer's memory using punch cards and then, after that, magnetic tapes. Computer memory space was limited, and when the instructions to control a computer were moved onto a disk drive, such as a floppy disk or internal HDD, it was considered cutting-edge technology.

DOS is also used to describe several similar command-line disk operating systems. Early computers, such as the Commodore 64, Atari 800 and Apple II, all featured a disk operating system, including Commodore Business Machines DOS, Atari DOS and Apple DOS, respectively. DOS/360 was an OS for IBM mainframes, which first appeared in 1966, but it is unrelated to the 8086-based DOS of the 1980s.

How does a disk operating system work?

When a computer is powered on it goes through various steps called the boot process. For a computer running a disk operating system, the following six steps are standard:

1. The read-only memory (ROM) bootstrap loader reads the Master Boot Record and passes control over to it.
2. The boot record loads the disk operating system into memory, and it takes control of the machine.
3. The computer transfers data stored on a magnetic disk to its main memory, the random access memory.
4. It also transfers data to external devices attached to the computer, such as a computer screen or printer.
5. The computer provides various application programming interfaces for programs like character input/output (I/O), memory management, program loading and termination, as well as handling input from the user through a keyboard.
6. The OS also provides file management that organizes, reads and writes files on storage. The files are organized in a hierarchical structure of directories, subdirectories and files.

A disk operating system doesn't have a graphical user interface (GUI). Its interface is character-based, so users must type commands in the command line to indicate what actions they want.

EVALUATION:    1. Define disk operating system

2. Describe how disk operating system works

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively