1.1.3 Input, Output and Storage

what is an input device?

a device that can be used to put data and information into a computer e.g. keyboards, webcams, barcode readers, etc

what is an output device?

a device that can be used to send information from a computer to another component e.g. speakers, printers, projectors, etc

why is a touch screen both an input and an output device?

outputs information as a monitor but also receives touch input

how do optical devices work?

• read from and written to using lasers

• binary is represented by portions of the disc that either reflect or scatter light (pits = 0 and lands = 1)

what are examples of optical devices?

• CDs

• DVDs

• Blu-Ray

what are some features of CDs?

• compact discs

• use optical technology to store small quantities of information

• most commonly used for audio file and digital images

• small thin and light which makes them portable

• easily damaged by scratches

• have limited storage and low transfer speeds

what are some features of DVDs?

• digital versatile discs

• higher storage capacity than CDs

• used for storing digital videos

what are some features of Blu-Ray?

• have 5x the storage of DVDs

• used for storing high-resolution films

how do magnetic devices work?

represent binary through two states - polarised and unpolarised

what are examples of magnetic devices?

• hard disk drives

• magnetic tape

• floppy disks

what are features of hard disk drives?

• high capacities of 500GB to 5TB

• work by rotating platters at high speeds under a read/write head on an actuating arm

• have slow data transfer speeds

• not portable as they have many moving parts

what are features of magnetic tape?

• first used to record data in the 1950s

• popular storage medium until the 1980s

• space consuming way to store data

what are features of floppy disks?

• thin magnetic disk enclosed in plastic to protect from dirt and dust

• extremely portable due to small size and weight

• typical storage of 1MB

what are features of flash storage?

• fast and compact

• silicon semiconductors form NAND and NOR gates

• logic gates used to store electrical charge in high or low states

• information stored in blocks to form pages

• NOR used for small quantities of data

• NAND used for large files

• can be erased and reprogrammed electronically

• non-volatile

• more expensive than other storage types

what is an example of flash storage?

solid state drives

what are features of solid state drives?

• extremely light and portable

• no moving parts

• less prone to damage than hard disk drives

• high data transfer speeds

• expensive

• limited lifespan

what is stored in primary storage?

code instructions to execute and files that are required by running programs

what are features of RAM?

• random access memory

• used to store data and programs the computer is currently using

• volatile

• speeds up computer’s execution

• higher access speeds than flash memory

• more expensive than secondary storage

what are features of ROM?

• read only memory

• non-volatile

• cannot be modified

• stores BIOS

what is virtual storage?

the name given to storing information remotely so it can be accessed by any computer with access to the same system e.g. over the Internet

what are examples of virtual storage?

• cloud storage devices

• networked storage used in offices and schools

what is an advantage of virtual memory?

convenient to access and share

what are disadvantages of virtual memory?

• limits user’s network speed

• high cost