Storage and Connectivity DevicesMr ContiYear 9Lesson 4

Key Words for Todays Lesson• Kilobyte (KB)• Megabyte (MB)• ROM• RAM• Storage• Magnetizing

• Optical• Medium• Network card (NIC)• Modem• Router• Switch

The amount of data stored in a computer is measured in kilobytes (KB).

1 megabyte (MB) is 1,000 KB (220)1 gigabyte (GB) is 1,000 MB (230)1 terabyte (TB) is 1,000 GB (240).

Confusingly, 1KB is actually 1,024 bytes (210), not 1,000 as you might expect, but most people think in multiples of 1,000.

Read Only Memory (ROM)

When a computer is first switched on, it needs to load up the BIOS (Basic Input/Output System) and basic instructions for the hardware.

These are stored in ROM (Read Only Memory).

This type of memory is called non-volatile because it retains the data.

Data stored in ROM remains there even when the computer is switched off.

ROM can be found on the motherboard.

Random Access Memory (RAM)

When a computer is started operating instructions, any computer programs that are opened and data are stored in the RAM (Random Access Memory) temporarily.

When the computer is switched off all the data is cleared from the RAM.

This type of memory is called volatile because it only stores the data while the computer is switched on.

RAM sticks are found on the motherboard.

The contents of RAM are constantly rewritten as the data is processed.

There are two types of storage device:

Storage devices and media

The medium is what the data is actually stored on. Examples of media include floppy disks, CD-ROM and zip disks.

those that store data by magnetizing a special material that coats the surface of a disk,

and others that store data using optical technology to etch the data onto a plastic-coated metal disk. Laser beams are then passed over the surface to read the data.

Storage Task• Pupil Resources• ICT• Mr Conti• Year 9• Lesson 4• L4 Storage Task

Answers

Whole Class Task• Work out what you are• Work out where you should

stand

Socrative Task• www.socrative.com• Room Number 161099

Network Devices

Every computer on a network needs a network interface card (NIC) which is connected to the motherboard inside the computer.

A cable plugs into the card, and the other end of the cable plugs into a switch.

The switch is then linked to the server.

switch

NIC

Building a network

When you connect to the Internet you connect your computer to an Internet Service Provider (ISP). This is done through telephone or cable services.

Computer signals are digital and normal telephone lines are analogue, so you need an analogue to digital converter if you are using an analogue telephone line. This is called a modem (modulator/demodulator).

In order for a computer to function as part of a network,it has to have a special piece of equipment called a network interface card (NIC) installed.

A NIC has a port for a network cable to be connected.

NICs are still very common, but increasingly people are using wireless network cards or wireless USB adaptors.

It is possible to connect computers on a LAN without using wires.

A wireless network card is similar to a standard NIC but has a transmitter/receiver forsending signals via radio waves.

Wireless networks are popular as they allow the user more freedom, such as working outside.

AFL CheckHow did you do?

Copy the actions below to show how much you agree with the statements.

• I understand what RAM and ROM is.• I know the two types of storage device.• I can give you an example of a medium.• I am able to explain the job of a router.

Extension Task•Explain one advantage of using writeable

DVDs instead of writable CDs for storing data.

•Describe two features of a USB memory stick that make it suitable for transferring files between computers.