2.6 operating system

Question 1

what is an operating system (basic definition)

Answer 1

• is software that manages computer hardware and software resources
• all computer programs (other that basic firmware systems) require an os to function

Question 2

examples of an os

Answer 2

• windows
• linux
• IOS
• android

Question 3

what us an operating system (its function)

Answer 3

• it provides a layer of software services which are used to interact with the hardware (it acts as a layer between the software and user an the hardware)
• os can be extremely large and so no all of the os will be loaded into the main memory
• the kernel is loaded into RAM when the computer boots up and this is responsible for managing processes, hardware and other important low level tasks

Question 4

functions of os: process management

Answer 4

ensuring that different processes/programs can be run and in a multi-tasking os appearing to run simultaneously using scheduling

(makes use of interrupt handling)

Question 5

functions of os: input/output management

Answer 5

communicating with devices such as keyboards, mice, printers, monitors etc

(makes use of interrupt handling)

Question 6

functions of os: backing store management

Answer 6

ensuring data can be read/written to disk drives, maintaining a hierarchical file system etc

(makes use of interrupt handling)

Question 7

functions of os: memory management

Answer 7

ensuring that programs and data can share memory and are stored correctly without interfering with each other

Question 8

functions of os: human computer interface

Answer 8

to display information to the user and accept input

Question 9

functions of os: utilities

Answer 9

software that comes with the os to help with the running of the computer, eg. file management, backup, virus scanning etc

Question 10

functions of os: security

Answer 10

os will typically have security built-in such as login/password, encryption, file access rights etc

Question 11

functions of the os that are carried out by the kernel

Answer 11

• interrupt handling
• input/output management
• scheduling
• memory management

Question 12

what do hardware drivers do

Answer 12

perform the translation between the generic os instructions and the specify binary control signals that the hardware understands

(if you buy a printer, mouse, keyboard etc and there isn’t a compatible driver available for it for the os you are using, then it wont work)

Question 13

what is the kernel

Answer 13

the central component of an os that communicates with hardware and software

Question 14

describe the purpose of an os in a personal computer

Answer 14

• provides a user interface, typically WIMP
• provides an interface to peripherals devices such as keyboards, mouses and printer
• running software programs, by loading program code and data into RAM then activating the CPU to execute the program
• allowing multiple programs to be active at the same time by sharing processor time
• providing an interface for local or wide area networking
• providing the device drivers to allow new peripherals to be installed
• controlling the storage of files in secondary storage, and displaying a catalogue of programs and data files
• providing security to prevent unauthorised access
• allowing multiple users to have personal secure access through a password system
• responding to system errors in a way which minimises data loss

Question 15

managing backing store

Answer 15

• storage devices are managed by the is which will be able to read and write files and folders/directories and maintain a hierarchal structure, file access rights
• information about files is stored in an index known as file allocation table (fat), which stores the locations of all files on the drive together with meta data about file including file name, creation/ modify date, size, file access rights