Computer Components

RAM – Random Access Memory• Computers use two types of storage: Temporary

and Permanent• Long-term storage is for information computers

use again and again, such as the instructions the computer prepares itself with every time you turn it on. These instructions are stored in read only memory (ROM), a type of memory that does not accept new information.

• RAM is a volatile storage device meaning that when the computer is switched off everything stored on this temporary storage device will be lost.

• The more computer memory, the better the computer will run and the better it will handle programs and software.

• RAM is generally measured in Mhz, and most commonly seen in the types of SDRAM, DDRRAM, DDR2RAM and now DDR3 SDRAM.

So what is Computer RAM?• The words 'random access memory'

refers to the fact that any byte of data can be accessed directly by the computer instead of it searching in order till it finds it.

• RAM operates at very fast speeds and is crucial to the health of a computer. RAM was measured in ns (nanoseconds) which equals one billionth of a second but with the introduction of SDRAM is now measured in MHz (megahertz).

• Like many components RAM is placed into slots in the motherboard where it can be upgraded.

• Memory is needed for all computer operations and it is important to have enough.

Types of RAM

• There are two basic types of RAM: Dynamic RAM (DRAM) and Static RAM (SRAM).

• Dynamic RAM is the more common and needs to be refreshed thousands of times per second.

• Static RAM does not need to be refreshed making it a lot faster but also much more expensive.

DDR RAM

• DDR RAM or DDR SDRAM. It stands for: Double Data Rate Synchronous Dynamic Random Access Memory

DDR Specifications• DDR RAM (Double Data Rate) which means it can transfer double the data

without increasing the clock speed. – Typical clock speeds were 100Mhz, 133Mhz, 166Mhz and 200MHz.

• Megabyte(MB) and Gigabytes (GB) measure the size of DDR SD-RAM. They vary in size from 128mb-1Gb. The common sizes are 256mb, 512mb and 1Gb. DDR2 RAM and DDR3 RAM have both increased the speed and size even further and they are similar prices so if possible go for DDR2 or DDR3.

DDR2 RAM• DDR2 RAM or DDR2 SDRAM is a type of computer memory. It stands

for: Double Data Rate 2 Synchronous Dynamic Random Access Memory.

DDR2 Specifications• DDR2 RAM (Double Data Rate) which means it can transfer double the data

without increasing the clock speed. Typical clock speeds were 100Mhz, 133Mhz, 166Mhz, 200Mhz and 266MHz.

• Megabyte (MB) and Gigabytes (GB) measure the size of DDR SD-RAM. They vary in size from 256mb-2Gb. The common sizes are 512mb, 1Gb and 2Gb. DDR SDRAM and DDR2 SDRAM have both increased the speed and size even further and they are similar prices so if possible go for DDR2 or DDR3.

SDRAM• SDRAM or SDR SDRAM is a type of computer memory. SDR SDRAM stands

for: Single DataRate Synchronous Dynamic Random Access Memory. So what does that mean?

SDRAM Specifications• SDRAM or SDR (Single Data Rate) SD-RAM can accept one command and transfer

one piece of data per clock cycle. Typical clock speeds were 66Mhz, 100Mhz and 133MHz and for more money 150Mhz.

• Megabyte (MB) size in SDR SD-RAM varies from 8mb-512mb. The common sizes were 32mb, 64mb and 128mb. 256mb and 512mb sticks can be purchased for a little bit more. However, SD-RAM is no longer made so it has become more and more expensive to buy second hand. DDR and DDR2 RAM which are both a lot faster and better can be bought at a cheaper price.

Different Types of RAM Compared

Motherboards• Everything in the computer connects to

the motherboard.• The Power Supply powers up the

motherboard, the CPU, Memory, Hard Drives, are all connected to the motherboard.

• In recent motherboards, the sound cards and even the network cards are built into the motherboard making it unnecessary to purchase additional cards. – However, built in components makes

upgrading components difficult.• The chipset is the most important

component of a motherboard and it determines the capabilities and features .

• Motherboard’s can come with different options such as more expansion slots, Wi-Fi or a 1394 connection.

Central Processing Unit (CPU)• The CPU is the “brain” of a computer. • CPU speed is measured in hertz.

– Previously, measured in megahertz – one million cycles per second

– Today, measured in gigahertz – one billion cycles per second– The higher the amount of hertz the greater amounts of cycles

can be completed and more information will be processed. • Faster processors create more heat which means fans have

to be upgraded.• The CPU is placed in the CPU socket and forms an electrical

interface with the motherboard.• Regardless of the RAM or Hard Drive the CPU decides what and

how fast programs will run on the computer.• Modern processors have millions of transistors placed onto the

little square which is called a die. The CPU is responsible for processing codes and instructions through to the motherboard which sends the information through to the graphics card where it then travels to your monitor and then appears on your screen.

• Intel released the first CPU processor which was the 4004 in the year of 1971. It ran at 740kHz (740,000 hertz) compared to the more modern computers that can run up to 3Ghz (3,000,000,000 hertz).

Hard Drive

What does a Hard Drive do?

• The hard drive is a permanent storage device. • Without the Hard Drive the computer would not be able to

load the operating system.– Hard Drives are measured in Gigabytes (one billion bytes).

• A computer hard drive is the place where computer data is stored. A HDD (Hard Disk Drive) is generally referred to as the secondary computer storage device, as the RAM (Random Access Memory) is the primary. – Data that is stored on the RAM is volatile meaning when

the computer is shut down then the information will be lost.• A hard drive is a permanent storage device, so even when

the computer is turned off the information will still be there.

How does a Hard Drive work?

• A hard drive uses circular platters to store data which are kept in pristine condition and are very good mirrors. – If you open a hard drive case, the air will

contaminate the platters and it is unlikely that it would work again.

– The actuator arm runs between the platters reading the information in 1's and 0's (BINARY). The head of this arm reads data even when the disk is running at 7200rpms (a common hard drive speed).

• This means that the platter is doing 7200 rounds per minute. – More recent computer hard drives can now do

up to 15,000rpms. – As the platters go round and round the head

reads it and processes the information which then proceeds to the connector which connects to the computer.

Hard Drive SpecificationsExternal or Internal?• All the hard drives that are inside a computer are called internal

hard drives. • An External Hard Drive sits outside the computer and is

connected to the computer through USB, Firewire or eSata.– External drives are very useful for backing up

your computer and for transferring files to two locations. – External drives are also very portable.

Hard Drive Capacity• A computer hard drive is measured in Gigabytes. Different files

take more space. Video files and pictures take up a lot of room, but simple text files take next to nothing. The operating system and program files take up space as well.– Hard drive capacities vary between 1Gb (or less) to 2Tb

(maybe even bigger).Hard Drive Manufacturers• Western Digital• Seagate• Samsung• Iomega• Hitachi

It is very important to back up your hard drive! Do not learn the hard way!

Common Hard Drive Specs.Which technology is right for me?

5,400 RPM hard drive disk (HDD)

7,200 RPM hard drive disk (HDD)

Solid State Drive (Offered only on select systems only)

Performance Basic Performance Faster, quieter and more durable than

standard hard drives

Capacity in Gigabytes (GB)

250, 320, 500, and 640

250, 320, 500, and 750

128, 256 and 512

Durability Standard Standard Highly Shock Resistant

Hard Drive Connectors

• There are currently several types of connector cables in a common hard drive.– IDE Ribbon Cable– SCSI Cable– SATA Cable– USB – Universal

Serial Bus

CD/DVD Drives or Optical Drive• CD/DVD Drives are another storage

device in a computer. CD Drives are used to read CD's with information on them such as an operating system, programs or data files.

• CD-RW and DVD-RW write data to blank disks.

• CD Drives are measured by their read and write speeds. 8x, 16x, 24x

• Drives take up a lot of space and small flash drives may make them obsolete.

Video Cards• A video card is another

compulsory component in a computer.

• Information goes into the video card and then is transmitted to the monitor where the information is displayed.

• Some motherboards have the graphics card built in, but the majority need a separate card that plugs into the motherboard.– Video cards that are built into

the motherboard make upgrading more difficult.

Sound Card• A sound card is another

extra that can be added to your computer.

• A sound card translates signals into sounds that can be played back through speakers.

• Many motherboards have a sound card incorporated in the motherboard, but for those that don't it is possible to get one.

Monitors• Without a display or monitor…

What is the point?• The computer monitor

connects to the graphics card and it displays a picture on the screen.

• Computer monitors come in different types: – CRT (Cathode Ray Tube) which

are block monitors.– LCD (Liquid Crystal Display)

which are very thin.– LEDs (Light Emitting Diodes)– Touch screen monitors are now

also available.

Network Card• A Computer Network Card or a LAN

(Local Area Network) card required to connect your computer to different devices, the internet and WIFI.

• LAN ports are often incorporated on the motherboard.– There are wireless network cards, USB

network adapters, typical network cards and more.

• A network card is a piece of computer hardware, that is designed to allow computers to communicate over a network.

Modem• A modem offers us access to the internet.• The term modem means 'modulator-demodulator' – it

modulates an analogue carrier signal to encode digital information and demodulates the signal to decode the information. – In its modern form, wireless modems, which are examined in

part three of this guide, convert digital data into radio signals and back.

• Originally modems had speeds of around 300bps and this was maintained until 1983 when 1200bps modems were introduced. However, by 1998 56kbps became the standard.– However, the limit to this technology was the 56k modem.

• In 1999 modems emerged with theoretical speeds of up to 8Mbps. Now even faster up to 50Mbps.

• A wireless router is usually added to a modem to broadcast WIFI broadband access over a LAN.

• Modem routers are as the name suggests routers with modems built-in. Excellent - you can get rid of one of those boxes and save power at the same time!

Modem Connections and Networking

Wireless Router• Dial up is dead and now we all have routers with a

couple of LAN ports, and one or more antennas for WIFI. A router performs three main functions:

1. The router - It is a clever receptionist that redirects data to whatever device is requested it.o Always have a password on a secure network.

2. A network switch – The router splits a single network usually four times so that different devices can access the network. Desktop, laptop, TV, IPad, IPhone etc.o Make sure your router has a gigabit switch which will

make it much faster and not the old 100 mbit.

3. The wireless access point – This function really does the same thing as the switch but does so wirelessly.o Most new routers have a “wireless-n” (802.11n) access

point. This is much better over the older “g” standard. Look for “dual band” for the absolute best possible speeds. • “n” may not be compatible on some devices.

Other components to consider…

• Webcam• Operating System– Windows– Mac

• Speakers – Sound • Sync to TV• Apple TV is coming…

Printer Copier Fax Scanner

All-in-One

References• Intel Corporation (2012). Introduction to Computers. Retrieved February 01, 2012 from

http://www97.intel.com/en/TheJourneyInside/ExploreTheCurriculum/EC_IntroductionToComputers/ICLesson2/

• Computer Hardware Explained (2007-2007) Understand these Computer Hardware Terms? Retrieved February 01, 2012 from http://www.computer-hardware-explained.com/

• ViewSonic Corporation (2000-2011) VX2250wm-LED. Retrieved February 04, 2012 from http://www.viewsonic.com/products/vx2250wmled.htm

• Moneysupermarket.com Ltd (2010). Guide to broadband hardware. Retrieved February 05, 2012 from http://www.moneysupermarket.com/broadband/hardware/

• White Rabbit Ltd (2009). Wireless Router Types - Broadband vs Modem Routers. Retrieved February 05, 2012 from http://www.bestrouter.co.uk/articles/modem-or-broadband-wireless-routers.html

• Roytank.com (2011). Wireless routers explained. Retrieved February 05, 2012 from http://www.roytanck.com/2011/01/12/wireless-routers-explained/