1. Nat 4/5 Computing Science Lesson 8: Input, Output and Backing Storage
Computer Systems
Nat 4/5 Computing Science
Lesson 8:
Input, Output and Backing Storage

2. Lesson Aims By the end of this lesson: Pupils will be able to:
Describe the features, functions and uses of these input devices :
Keyboard, Mouse
Microphone, sound card
Trackpad, graphics tablet, touch-sensitive screen
Joystick
digital still camera, digital video camera
Sanner
Webcam
Dataglove
Interactive whiteboard

3. More aims By the end of this lesson: Pupils will be able to:
Describe the features, functions and uses of these output devices:-
Monitor
inkjet printer, photo printing, 3-D printing, laser printers, plotter
loudspeakers, headphones, sound card
Graphics card
Headset
Multimedia projector
Compare devices using appropriate characteristics including - resolution, capacity, speed of data transfer, cost

4. Nat 4/5
Input Devices
An input device is hardware that lets you put information INTO the computer e.g.
Keyboard, mouse
Microphone, sound card
Trackpad, graphics tablet, touch sensitive screen
Joystick
Digital Still Camera / digital video camera
Scanner
Webcam
Data glove

5. Input devices

6. More input devices

7. Nat 4/5
Output Devices
An output device is hardware that gives the user information from the computer system e.g.
Monitor
Inkjet printer, photo printing, 3-D printing, laser printers, plotter
loudspeakers, headphones, sound card
Graphics card
Headset
Multimedia projector

8. Output Devices - monitors

9. Output devices

10. Nat 4/5
Input/output Devices
You have to be able to compare these devices in terms of appropriate characteristics such as:
Resolution
Speed of data transfer
Cost – initial cost and running cost

11. Examples Type of printer Purchase price Resolution (dpi) Speed (ppm)
Ink/toner
Interface
Colour?
Y/N
CANON iP7250 Wireless Photo Inkjet Printer
49.99
9600 x 2400
15 b&w
10 colour
Ink
USB, WiFi Y
EPSON WorkForce Pro WP-4535DWF Wireless All-in-One Inkjet Printer
£179.99
4800 x 1200
26 b&w
24 colour
USB, Ethernet, WiFi
BROTHER HL2130 Compact Monochrome Laser Printer
2400 x 600 20
Toner
USB 2 N
Samsung CLX-9250ND/SEE Colour Laser A3 MFP
£19,123
9600 x 600 25
Ethernet, USB?

12. Backing Storage

13. a group of 8 bits – Single Letter
Nat 4/5
Storage Terms
Term
Abbreviation
Description
Bit
binary digit, 0 or 1
BIGGER ->
Byte
a group of 8 bits – Single Letter
Kilobyte Kb
1024 bytes
Megabyte Mb
1024 Kilobytes
Gigabyte Gb
1024 Megabytes
Terabyte Tb
1024 Gigabytes

14. Types Of Access Sequential Access Direct/Random Access
Nat 4/5
Types Of Access
Sequential Access
Direct/Random Access
To go from file A to file Z in a sequential-access system, you must pass through all files in order.
Sequential access is sometimes called serial access
Refers to the ability to access data at random. In a random-access system, you can jump directly to file Z.
Disks are random access media, whereas tapes are sequential access media

15. Nat 4/5
Backing Storage
Backing storage is used to save permanent copies of your files onto.
There are 3 main types
Magnetic
These use magnetic fields to store the data
Floppy Disks/Hard Disk Drives
Magnetic Tapes
Optical
These store data by means of lasers ‘burning’ a disk
CDROM/DVD/Blue Ray
Solid State (N5)
This uses no moving parts at all, uses memory chips
USB Drives
SSD Hard Drives

16. Magnetic Storage Most likely a Hard Disk Drive Points to look for are:
Need to know it’s capacity
How much it stores
It’s speed – how fast the disk is turning
Written as rpm – revolutions per minute
High capacity and high speed are best
Can be internal or external (portable)

17. Hard Disk Drives (HDD’s)
Nat 4/5
Hard Disk Drives (HDD’s)
Hard Disk Drives are usually stored inside the computer. They use disks of metal which are magnetically charged.
These are read by a small head –which moves over the disks.
Very large storage capacity
Very fast data access speeds
Type Of Access
Direct/Random
Capacity
Up to 3TB
Portability
Internal model (NO) External models (YES)
Price
Approx £40 - £220

18. Magnetic Tape Magnetic tapes are essentially the same as music tapes.
Nat 4/5
Magnetic Tape
Magnetic tapes are essentially the same as music tapes.
To access a file you have to sequentially go through every file by fast forwarding or rewinding.
They are however relatively cheap and easy to store.
Often used for backups
Type Of Access
Sequential
Capacity
Up to 200GB
Portability
Very portable, requires a tape drive
Transfer Rate
Up to 20Mbps
Price
Up to £20 per tape

19. Optical Storage CD (Compact Disc) DVD(Digital versatile Disc)
N4/N5
Optical Storage
CD (Compact Disc)
DVD(Digital versatile Disc)
BD (Blu-ray Disc)
Need to know it’s capacity
Some disks have more than one layer – holographic discs!
It’s form
ROM = Read Only – cannot be changed
R = Writable – can write data on the disc
RW = Rewriteable – can write data on the disc and change or delete it later

20. Optical Storage – CD/DVD
Nat 4/5
Optical Storage – CD/DVD
CD, DVD, and BD’s are optical media
A spiral track is used to store the data
A laser is used to burn holes (pits) into
the surface of the disk on a ROM disc
A lower power laser is used to read the data
Type Of Access
Direct/Random
Capacity
CD: 700MB (80 minutes audio)
DVD 4.7GB up to 50GB Blu Ray
Portability
Very portable, requires another drive
Price
CDR: 20-30p DVDR: 30p-£1

21. Optical Storage capacities
Capacity
CD-ROM
CD-R
CD-RW
DVD-ROM
DVD-R
DVD-RW
Blu-Ray
700Mb
4.7Gb
25-50Gb

22. Uses of optical discs
CD-ROM - distribute data: software (e.g. office applications or games), music, electronic books e.g. an encyclopaedia with sound and video
DVD-ROM - larger capacity so used to distribute video
Blu-Ray discs - even larger capacity so used for HD video

23. Storing your data on optical disc
CD-R, DVD-R = Writeable storage media –you can “burn” you files onto them
CD-RW, DVD-RW = re-writeable storage media – you can write data on the disc and change it later

24. Solid State Devices (SSD)N5
Solid State Devices (SSD)
Soli State means “no moving parts” – data stored on chips
Known as ‘Flash Memory’
Many portable computers contain built-in SSD’s
Portable
Rewritable
Data can be read much faster than either optical or magnetic devices
Hybrid drives contain HDD as well as SSD
Uses less power than optical and magnetic drives
Large capacity

25. USB Flash Drives Very robust. Nat 4/5
These are often used in MP3 – Players – Ipod Nano/Shuffle uses this.
Some are even waterproof or branded with company logos
Type Of Access
Direct/Random
Capacity
Up to 128GB
Portability
Very portable, only requires USB port
Transfer Rate
10-30MBps
Price
£10-£100+

26. Summary There are three main types of backing storage
Optical
Magnetic
Solid State
There are two main types of access
Sequential
Direct/Random
Input Devices put information INTO the computer
Output Devices get information FROM the computer

27. Lesson 8 - Task
Worksheet 8