Components of a computing system

name some operating systems

• microsoft

• Google

• apple

• Linus Torvalds

system software

System software is the software that provides a platform for other software to work

It includes operating systems and utility programs

Operating Systems

Operating systems manage computer hardware, users and the resources used by software

operating systems are responsible for managing:

• The user interface

• Memory management

• multitasking

• Peripheral management and drivers

• user management

• file management

User interfaces

User interfaces provide a method for users to interact with a computer– windows, icons, menus, pointers, drag/drop – can be GUI, menu interface or command line interface

GUIs: graphical user interface

• (GUI) Allows the user to interact with the Computer in a visual and intuitive way.

• In the past, GUIs have been WIMP based (using Windows, Icons, Menus and Pointers).

Types of User Interfaces

• Gui

• menu- drivern interface

• command line interface

  text commands are entered into the interface

• voice activated

• real-time

  sensors detect inputs

command line interface

• text commands are entered into the computer

• they are less resource heavy than GUis

• great for expert users who know the commands it can be faster as it can be far faster to enter commands than using a mouse.

• require less RAM

• requires much less hard disk storage space.

menu- drivern interfaces

menu driven interface are often used by devices that have a dedicated function including:

• mp3 players

• ATM machines

• self service checkouts

Memory management

manages programs and data stored in RAM, frees up memory when a program is closed.

Multitasking

Multi tasking is where an operating system manages many tasks happening at the same time.

• this may be having a web browser open whilst playing music and messaging friends

• many other background processes are also running

• the operating system decides which process will next run on the CPU and for how long.

Interrupts

• signals sent to the CPU by external devices to indicate an event that needs immediate attention.

• they tell the CPU to suspend its current activities and execute appropriate instructions

• hardware interrupts are generated by harware devices - for example, printer out of paper

• software interrupts are generated by programs - for example , a divide by zero error will cause an error message to be displayed.

Peripheral management and drivers

the operating system must manage getting inputs from and sending outputs to pheriphal devices.

peripherals include mice, keyboard, printers , displays , digital cameras and graphics tablet.

device driver

a device driver is a program that controls periphal devices such as printers, mice and displays

sending data to a printer

the data will be sent to a print queue or buffer which is a special area of memory in a computer print server or the printer itself.Text

disk and file managemnet

the hard disk in a computer is a storage pheriphal. The operating system:

• manages where on the disk files are written

• keeps track of where they are so they can be retrieved.

• make sure no file overwrites another file.

file managment

the followig features are:

• naming files

• allocating files to folders

• moving files

• saving files

• coping files

• deleting files

they organize files on storage devices

User management

– management of usernames and passwords along with what they have permission to access

utility software

• the operating system controls and manages the computer sytem.

• utility programs perform extra functionality and housekeeping tasks that keep computers running efficiently.

4 types of utility software

• encryprion software

• defragmentation software

• data compression

• disk clean up tools, disk formatters, anti-virus software

encryption software

it will encode a file so that it cannot be read without a decryption key.

how do you know If the connection to a website is encrypted

web browsers usually show a padlock for sites that are using HTTPS ( hypertext Transfer Protocol Secure)

what organsiations encrypt their emails or file attachments?

• councils when discussing sensitive personal information such a as personal needs or disabilities.

• accountants discussing financial information or companies

• companies sharing confidential internal files

encrytion tools

encrytion software utilities are commonly used to:

• encrpt entire hard disks so that the data cannot be understood if the computer is stolen

• encryt files and folders on a portable disk such as USB removal storgae

• encrypt communication with websites

• encrypt data ain an organisations database - especially sensitive data such as passwords

disk defragmentation

Different sized files saved on disk are deleted over time creating gaps on the disk. New files fill up the gaps, but may need more space than the gap provides resulting in fragments of the file being spread across the disk. Defragmentation rearranges parts of files back to contiguous space. Makes access quicker.

(Defragmentation software will put all fragments of a file together so that the file can be read faster.)

Data compression software

• Utilities such as WinZip enable users to compress and decompress files or folders

• This reduces the amount of storage space needed on a disk

• If sending the files, it reduces the amount of data that is sent

• Compression may allow attachments to be sent via email that would otherwise have been larger than a file-size limit

• More data can be stored on backup media

in summary ( Defragmentation softaware will put all fragments of a file together so that the file can be read faster).

the main components of a computer system

• main memory

• secondary storage

• input devices

• output devices

The CPU

central processing unit is the brain of a computer system. It processess instructions