Computing GCSE 1.5 Systems Software

What is an operating system?

software that allows the computer to run applications

What is utility system software?

helps users configure, analyse, optimise and maintain a computer

How can defragmentation overcome the issue of a slow computer system?

- files on the hard disc drive are moved
- empty spaces are collected together
- files are moved to be stored together

What are the main function of an OS?

- communicate with internal and external hardware via device drivers
- provide a user interface, allowing a user to interact with the computer
- provide a platform for different applications to run
- allow the computer to multi-task by controlling memory resources and the CPU
- deal with file management and disk management
- manage the security of the system

What is the kernel?

the heart of the operating system and is responsible for looking after "the most low-level hardware operations"

What do operating systems use device driver software for?

to communicate with internal hardware or peripherals connected to the computer system

What is a device driver?

Software that uses signals to control the computers' devices.

What does every piece of hardware connected to the computer system require?

a device driver

What do device drivers essentially act as?

a 'translator' for the signals between OS and hardware

What does a user interface allow the user to do?

Interact with a computer system

What is a user interface?

a computer design that allows the user to interact with the computer

What is meant by a graphical user interface?

icons to represent actions and resources

What are GUI's designed for?

to be easy for everyday users by being interactive, visual and intuitive

What are GUI systems optimised for?

specific input methods

What does CLI stand for?

Command Line Interface

What is a command line interface?

it is text based, the user enters specific commands to complete tasks

How is a CLI used?

user provides a text input using the computer keyboard and the computer displays text on the monitor

Compared to GUIs, what are CLIs?

they are less resource heavy

What is a disadvantage of CLIs?

they are not suitable for everyday users

What are advantages of CLIs?

they can be far more efficient and powerful than a GUI

What is multi tasking?

when you have more than one program open and running at the same time
many tasks that can be executed on a single computer at the same time

What does the processer do in multitasking?

allocates a small amount of time to each process and cycles between them

What do operating systems provide a platform to?

run applications

What does the OS help the CPU do?

carry out multi-tasking by efficiently managing memory and CPU processing time

What happens when an application is opened?

the OS moves the necessary parts of the application to memory followed by additional parts when they are required, the OS will decide if applications or features have been used recently- if not they may be removed from memory

What does the OS need to do to run multiple applications?

make sure that the applications dont overwrite or interfere with each other

What does a memory manager allocate?

certain applications certain memory addresses to make sure their processes are placed into separate locations

Why must other processes sometimes wait?

as only one application is processed by the CPU at a time

What does the OS divide CPU time between?

open applications and may prioritise certain processes in order for instructions to be executed in the most efficient order

What is systems software?

software which allows a computer to run and to be maintained

What are the two main types of system software?

operating system software and utility software

Where does the operating system sit?

between the users applications and the hardware, it enables applications to use the hardware resources

What are the 5 roles of the OS?

Memory Management
Peripheral Management
Multi-Tasking
Security
User Interface

What is memory management?

used to allocated free memory to programs that need it, and free up memory where it is not needed

What happens when you load an application?

the OS will copy the application to the RAM. In addition, the OS will ensure that each program that loads has its own space on the RAM

What are peripherals?

external devices not connected to the computers motherboard

What is peripheral management?

allows a computers external devices to communicate with the computer system

What does a GUI use to control the computer?

windows, icons, menus and pointers

What does a menu driver interface use to control a computer?

menus

What are features of a command line interface?

Commands must be typed correctly and in the right order or the command will not work
Experienced users who know the commands can work very quickly without having to find their way around menus
Command driven programs do not need to run in windows

What are features of a menu driven interface?

they are easy to use as the user does not have to remember sets of commands
they are user friendly - you can often guess your way around the options
they can be irritating if there are too many levels of menus to move around - with a command-line interface you can go to the option required immediately

What are features of a graphical user interface?

They are much easier to use for beginners
They can be irritating to experienced users when simple tasks require a number of operations
They use a lot of memory and processing power

What is file management and what is responsible for it?

a system that is used by the operating system to organise and keep track of files
it also deals with the naming, saving, movement, editing and deletion of data

What can operating systems be?

single user or multi user

What are single user operating systems?

allow only one user to use the computer at once

What are multi user operating systems?

allow several users to use the computer at the same time

What do user accounts allow?

different users to be granted access to specific date or resources on a computer system

What may operating systems have to prevent other users from accessing locked devices or accounts to steal information?

anti theft measures

What are examples of user management functions?

- allocation of an account
- access rights
- security

What is meant by user management?

The administrative feature of a computer system to allocate an account or control user access into a network.

How are files stored on a hard disk?

in available spaces ideally entire files would be stored together

What happens as files are moved, deleted and change size?

lots of small gaps begin to appear on the disk

How are the gaps filled up?

when writing files to the disk, the OS splits files into smaller blocks to fill up the gaps

What does a fragmented disk make?

reading and writing files slower as the read/write head has to move back and forth across the disk

What does defragmentation software reorganise?

data on the hard drive to put fragmented files back together, it also moves files to collect all the free space together which helps to prevent further fragmentation

Why doesnt fragmentation cause any problems with SSD's?

as they use flash storage with no moving parts

What are examples of utility system software?

- encryption software
- defragmentation
- data compression

What is defragmentation?

the process of physically organising the mass storage device into the smallest number of fragments

What is data compression?

when a device uses fewer bits to transmit the same amount of data

What is encryption?

Software which scrambles data before it is sent across a network or stored on a system

What is backup?

Making copies of data that can be restored in the event of a data loss

Why does a fragmented disk make a computer run slower?

as a fragmented disk takes longer to read/ write from

When is fragmentation caused?

when information is deleted from a hard drive and small gaps are left behind to be filled by new data

How does compression software reduce the size of an image?

Could use lossy/ lossless compression, lossless will not remove data permanently, lossy means original file will not be restored

Why can a computer access files faster after defragmentation?

does not have to move