Ict Notes

Only available on StudyMode
  • Download(s) : 18
  • Published : May 4, 2013
Open Document
Text Preview
Hardware and Software
Hardware: physical components that make up a computer system (keyboard, mouse) Software: programs that control the computer system with 2 types Systems software: allow the hardware to run properly

Applications software: allow the user to do specific tasks

Components of Computer Systems
A computer is made up of hardware and software with:
Input devices (inputting the data into the computer)- keyboard, mouse Output devices (data output from a computer)- monitor, printer Secondary storage devices- DVD R/W drive, removable hard drive

1 important part of the computer system consists of:
CPU- interprets the commands from the computer hardware and software -contains coding like BIOS to tell what the computer should carry out RAM- internal chip where data is temporarily stored when running applications ROM- storing informations that needs to be permanent

Hard disk- computer’s main memory

Operating Systems
* Controls the operation of the input, output and backing storage devices * Supervises the loading, running and storage of application programs * Deals with errors
* Maintains a computer log with the details of computer usage Examples:
CLI (Command line interfaces):
A user will type in instructions to choose options from menus, open softwares and more. (Commands need to be memorised to carry out basic operations) *Combination of letters and words, basically codes*

GUI (Graphical user interfaces):
A user will interact with a computer using pictures or symbols rather typing in a number of commands. (WIMP is used for PCs where a cursor moves and select icons)→ Daily life screen

Types of Computers
PCs and Laptops:
-PCs have separate monitor, mouse and keyboard and laptops, have all in 1 -PCs are not portable and laptops are
-Laptops have short battery life

Mainframe computers:
-Large computer system for jobs which require large memories and very fast processor time -Used for banking and insurance

Backing up data
* Copying of files and data to a different medium like disk, drive and more in case of a problem in the main storage device.

It is important to do so because:
-Data could be lost due to failure of the original storage device -Hackers could corrupt the data
-In case a file needs to be used somewhere else

Types of access
* The way data is stored and read by different backing storage devices. Serial access:
-Used on magnetic tape systems where the speed of access is not important like in utility billing. -When the magnetic tape needs updating, a new magnetic tape is used to merge the old data and the new data. Direct access:

-Using magnetic disks and optical media.
-Computer uses a key field to calculate where data has been stored then it is able to access the data directly from the calculated position. -Fast so used in online systems

Backing storage media
* All computer systems have some form of backing storage and have 3 types of magnetic, optical and solid state. Examples here are using magnetic data:
Fixed hard disk
-Main method used for data storage
-Usually stores disk operating system (DOS)
-Fast data transfer rate and large memory capacity
-Easily damaged and not portable

Portable hard disk drives
-Same way as a fixed hard disk but connected to the computer by a USB -Used as back up systems to prevent losing data
-Data transfer rate is fast and large memory capacity
-Can be damaged if dropped

Optical storage media
* CDs and DVDs all use optical read or write methods unlike tapes and hard disks. * They are all used to store music or film at least.
Examples:
CD-ROM and DVD-ROM
-Can’t be written over and can only be read
-Data is stored as a series of pits and lands in the metallic optical layer -Hold more data than floppy disks but data transfer rate is slower than hard disks

CD-R and DVD-R
-Recordable once only
-Used for store data to be kept for later use
-Cheaper than RW disks
-Not...
tracking img