Peripherals

Mr Arthur

Aims of Lesson 1

1. To go over the Computer Structure test

2. Begin Unit 3 – Peripherals

3. Discuss the functions of an interface Buffering Data Format conversion Voltage conversion

Interface

A piece of hardware that is positioned between the processor and peripheral

The interface allows the processor and peripherals to communicate and compensates for differences between the two, for example, speed

INTERFACE

Functions of the Interface

Buffering A part of the interface where data

is held temporarily while in transit between the processor and peripheral

1. Processor sends print job to printer

2. Job stored temporarily in buffer

3. Processor get on with other tasks

4. Job is printed when printer is ready

Other Interface Functions

Voltage conversion This is required if the

peripheral uses a different voltage from the standard 5V used by the processor

Analogue to Digital Conversion Used to convert

analogue signals like sound from a microphone into digital 1s and 0s

Computer Systems Question

1. What is the total addressable memory if you have a 16 bit address bus and an 32 bit data bus?

2. Give 1 advantage and 1 disadvantage of using ASCII over Unicode

3. I have an image of Bart Simpson with a bit depth of 16 bits. How many colours can I represent per pixel

4. How many bits are used to represent true colour5. List the 3 steps in the Memory Read Operation6. Name the 3 main types of RAM that can be found

in a computer system7. Name the 3 main buses connecting the processor

to input and output

Aims of Lesson 2

Last Lesson Discuss the functions

of an interface Buffering Data Format conversion Voltage conversion

Today’s Lesson More functions of an

interface Serial to Parallel

conversion Status Signals

Spoolers

Other Interface Functions

Serial to Parallel Conversion Serial sends the bits for each character one after

the other Parallel sends each character along separate

lines sumultaneously .i.e data bus

0 1 0 1 1

SERIAL

PARALLEL

1

1

1

0

0

SERIAL to PARALLEL conversion

Status Signals

The purpose of a status signal is to determine whether or not a peripheral device is ready to communicate

Signals could include Insert paper Printer busy Toner low

More printers also show status signals on a LCD panel on the printer

Spoolers

A spooler is a program which carries out a similar function to a buffer

The spooler uses an area of the hard disk to temporarily store print jobs

The data is held on disk and transferred to the printer gradually

Adv Buffer is limited to a fixed size depending on

RAM of printer Spooler may be used in a LAN on a

dedicated printer server

Aims of Lesson 3Last Lesson Discuss the functions of an

interface Buffering Data Format conversion Voltage conversion Serial to Parallel conversion Status Signals

Spoolers

Today’s Lesson Protocols Interface standards Solid state storage

Flash cards USB flash memory

Advantages of solid state

Protocols

An agreement or standard that is set up between the processor and the peripheral

Parity is an example of a protocol used for checking errors Even = adding a bit to each byte of data to

make the number of 1s even Odd = adding a bit to each byte of data to

make the number of 1s odd

1001 0011

0001 0011

Interface Standards

USB 1 = 12Mbps USB 2 = 480Mbs Firewire 800 PCI (peripheral

component interface)

Solid State Storage

A storage device that has no moving parts and uses Flash ROM Flash cards USB Flash memory Advantages

Physically small Robust with no moving

parts Use less power Range of capacities

Aims of Lesson 4So Far!! Discuss the functions

of an interface Buffering Data Format conversion Voltage conversion Serial to Parallel conversion Status Signals

Spoolers Protocols Interface standards Solid state storage

Flash cards USB flash memory

Advantages of solid state

Today’s Lesson Current Interface Trends

Increasing Interface speeds

Wireless communication between peripherals and CPU

Development Trends in Backing Storage

Blu-ray Holographic storage Reduced Physical size Lower storage cost

Class Quiz to revise Peripherals

Current Interface Trends

Increasing speeds USB1 = 12Mbps USB2 = 480Mbps

Wireless Communication Using Bluetooth and Wifi radio waves

to connect peripherals to the CPU

Development Trends in Backing Storage Blu-ray

Used for storing high definition video

BD-ROM, BD-R and BD-RE Laser beam in the drive is

coloured blue, producing a narrower beam and is able to store more data

Holographic storage Uses laser beams to record data

through the full depth of the device rather than just the surface

Reduced Physical size Lower cost per unit of storage

Peripherals Revision Quiz

1. What is an interface?2. Give 3 functions of an interface3. What is the difference between buffering

and spooling?4. Give 1 advantage of spooling over

buffering5. What is a status signal? Give 1 example to

reinforce your answer6. Parity is an example of a protocol. What is

even parity?

Peripherals Revision Quiz

7. Give 3 advantages of using a solid state storage device over non solid state

8. Give 2 current interface trends

9. Give 3 trends in backing storage at the present time