1.1.3 Input,Output and Storage

COMPLETE!!

What is an input device?

peripheral devices used to pass data into the computer (& allow users to communicate w/ computer)

Examples of input devices

• keyboard

• mouse

• biometrics

• temperature sensor

• cameras

• barcode scanner

• proximity sensor

• RFID scanner

• Infrared sensor

Describe a barcode

• representing data in a machine-readable form

• check digit at end of barcode

• when long code entered check digit calculated & compared to check digit at end of barcode

• if they do not match there was an input error

How do sensors work?

by converting an analogue signal into a digital form by an ADC (analogue to digital converter)

Main criteria for choosing an appropriate input device?

• cost

• speed

• accuracy

• reliability

Describe an RFID (Radio Frequency Identification)

• allows data to be transmitted wirelessly over radio waves

• made up of tags and reader

• tags = antenna(receiving & transmitting radio frequency sinals) & chip (processes signals)

• each tag = unique identifier

• reader transmits encoded radio signal to interrogate the tag

What is an output device?

peripheral devices used to report results of processing from a computer to the user (& allow the computer to communicate with the user)

Examples of output devices

• monitors

• printer

• speakers

• 3-D printers

• motors(actuator)

What is an actuator?

something that performs an action

3 different types of printers

• Inkjet(feel the ink)

• Laser (use lasers)

• Dot-Matrix (old,dots)

What are the two different types of memory?

• primary

• secondary

What is primary memory?

memory that can be directly accessed by the CPU

What type of memory are RAM and ROM?

primary storage

Features of RAM

• volatile (contents erased when no power)

• can be read from and written to

What is usually stored temporarily in RAM?

• user files

• applications software

• OS

Features of ROM

• non-volatile (contents remains with no power)

• read only

What is usually stored in ROM?

• OS

• BIOS bootstrap program

Secondary storage has slower… than RAM

access speeds

What are the 3 types of storage?

• Magnetic

• Optical

• Flash

Examples of magnetic storage devices

• hard disk drives

• magnetic tape drives

Examples of optical storage devices

• CDs

• DVDs

• Blu-ray discs

Examples of flash devices

• SSD (solid-state drives)

• USB flash drives

How do magnetic storage devices store data?

magnetising particles on a disk/tape

(two magnetic states representing binary 1 and 0)

How do optical storage devices store data?

using a laser to burn puts into the surface of the disc

How do solid state devices store data?

in flash memory cells

Hard Drive (Magnetic) advantages

• high capacity

• cheap

• reasonably quick

Hard Drive (Magnetic) disadvantages

• serial access - slow (one after the other)

• vulnerable to damage if dropped

Hard Drive (Magnetic) uses

• used in computers

Solid State Drive (Flash) advantages

• direct access - fast speed

• light and portable

• reliable

• not as vulnerable to damage if dropped

Solid State Drive (Flash) disadvantages

• more expensive than simple hard drive

• limited number of read/writes till they break

Solid State Drive (Flash) uses

• computers where speed is priority

CD, DVD + Blu - ray (Optical) advantages

• fast

• light and portable

• reliable

• not vulnerable to damage if dropped

• cheap

CD, DVD + Blu - ray (Optical) disadvantages

• limited capacity

• slow read write times

CD, DVD + Blu - ray (Optical) uses

distribution of software and films

USB pen drive (Flash) advantages

• cheap

• very portable

USB pen drive (Flash) disadvantages

• limited read write before stops working

USB pen drive (Flash) uses

carrying data from place to place

What is virtual storage?

storing data remotely so it can be accessed by any computer with access to the same system

Examples of virtual storage

• google drive

• microsoft one drive

Benefits of virtual storage

• scalability (easy to increase storage as capacity grows)

• accessibility(accessed from anywhere w/ internet)

• data protection (protects against lost data due to hardware)

• cost-effective (pay only for storage used)

Drawback of virtual storage

• dependence on internet

• security concerns

• ongoing costs (cost can add up overtime)

When a PC runs low on RAM it can move data from RAM → Hard Disc but what will this cause?

reduction in performance of PCs