1.1.3.Input, Output and storage (Chp2)

An input device is one which can be used to put data and information into a computer. e.g. keyboards, webcams, barcode reader, magnetic stripe reader

An output device is one which can be used to send information from the computer. e.g. a touchscreen outputs info in a visual way, monitor, speakers, printers, projectors

Optical devices are4 read from and written to using lasers. Binary info is represented by portions of the disk surface. The portions which are recessed, called pits scatter light when the laser is pointed at it - this represents 0. The flat portions surrounding the pits are called lands, which reflect light back at the laser to represent 1.

Digital video disc. higher storage capacity than CDs making them suited to store digital videos as they require more storage than audio files or photos.

Compact disc. They store small quantities of information. Most commonly used for audio files.

advancement over DVDs has they have more than 5x as much storage than DVDs making them useful for storing high-resolution films.

PROS = small, thin and light which makes them very portable. CONS = -easily damaged by scratches -limited storage capacity -relatively slow transfer speeds

They are devices which store info magnetically and represent binary information using two magnetic states: polarised and unpolarised. They are read by a read/write head.

PROS = -large storage capacities -any part of the platter can be accessed by read/write head on actuating arm. CONS = -slow data transfer speeds -tendency to become damages by movement due to their moving parts (delicate)

The technology makes use of silicon semi-conductors forming logic gates NAND and NOR to store electrical charge in 1 of 2 states. Used to represent binary True ir False.

• fast and compact • portable and light • no moving parts so more robust • non-volatile so don’t lose contents when power is lost.

• limited lifespan - high costs

• type of fast main memory used to store data and programs that the computer is currently using. This speeds up the computer’s execution as Ram has higher access speeds than flash. • volatile • can be accessed in any order at any time • read/write

non-volatile -read-only so cannot be modifies, therefore it stores instructions of BIOS

the name given to storing info remotely so that it can be accessed by any computer with access to the same system. e.g. over the internet. • it is convenient to access and share • its disadvantages include limitations of a user’s network speed and high costs.