Mr C JohnstonICT Teacher

www.computechedu.co.uk

BTEC IT Unit 02 - Lesson 03

Inside Computers #2 – Drives, Connectors and Internal Memory

Session Objectives

Know different properties of hard disk and optical drives,

Understand how hard drives and optical drives are attached to PCs and how they should be configured,

Be able to recognise different types of connector and explain the difference between serial and parallel transmission,

Understand the difference between ROM and RAM, and the purpose of cache memory.

REVISION. Hard Drive Key Characteristics

Brand, Model, Capacity (GB/TB), Interface Type (SATA, IDE, USB) Access Speed (MS), Rotation Speed (RPM), Number of heads, disks, cylinders, sectors, tracks Type of drive (traditional or solid state)

Optical Drive Key Characteristics Brand, Model, Type of disks can read/write (CD,CD-R,CD-RW,DVD,DVD+R(W),DVD-R(W),Blueray) Speed of read/write Cache Interface (SATA, IDE, USB)

Hard Drive Controllers – SATA1

SATA = Serial advanced technology attachment, Replacement for IDE / eIDE, SATA cables are much thinner that IDE cables so are not a messy in the case,

Each drive needs its own channel so uses the full bandwidth of the cable – cant daisy chain 2 drives like IDE so is faster and no need to play with jumpers!!

4x SATA Channels

IDE Cable SATA Cable

Hard Drive Controllers – SATA2

HDD

DVD-RW

MotherboardSATA connections

Drive data and power cables

BTEC Book – Unit 02 p7 (start at the Hard drive configuration and controllers heading)

Connect 2 hard disk drives and a DVD Rom drive correctly to a mother board using SATA connections

Extra Task In your own words explain the function of the hard disk drive in a

typical modern personal computer. The function means what its main job is. Include details of the different

types available.Remember explain means to give a detailed account of something with

reasons – include how it works, and why its required.

Peripherals1

A peripheral device is a hardware device (such as keyboards or printers) which are physically separated from a computer but important to its operations and under the computers control,

Input devices, storage devices and output devices all fall under the category of a “peripheral”.

Peripherals2

As peripherals are physically separate from the computer they need to be attached to the motherboard using different connectors and ports.

You need to be able to recognise different connectors and ports.

More information on connectors: http://www.labnol.org/gadgets/visual-guide-to-computer-cables-connectors/10694/

Serial vs Parallel Transmission

Data travels down cables either in serial or parallel. Serial data travels 1 bit at a time down a single cable, In parallel the data travels 8 bits at a time down a ribbon cable with 8 cables.

In general it is faster to transfer data in parallel rather than serial.. But this is not always the case

Universal Serial Bus (USB) Allows must external peripherals to be connected, Allows plug-and-play so OS recognises when device

plugged in and tries to install it – sometimes successful other times need driver – plug-and-pray, but is better than old days,

As you can change devices using USB ports when they are known as “hot-swappable”

Motherboards have lots of USB slots and can also use USB hubs to daisy chain devices together.

BTEC Book – Unit 02 p8 - 10

Extra Task In your own words explain the function of some typical peripherals which

help you use a modern personal computer. The function means what its main job is. Include details of the different

types available.Remember explain means to give a detailed account of something with

reasons – include how it works, and why its required.

Internal Memory Internal memory is used to store running programs and

the data being used by programs, There are two types of internal memory – ROM (read

only memory) and RAM (random access memory), ROM is used to store permanent data – BIOS and

Firmware information, RAM is volatile and only stores data and programs

temporarily whilst the system has power, Work which has not been saved in stored in RAM so a

computer crash or power out will result in the work been lost.

RAM We know that programs and data are stored in RAM –

however this is not quite true.. Programs are huge and therefore when we run lots at

the same they cant all be stored in RAM at once, Therefore the computer spends time swopping

temporary data between “virtual memory” on a HDD and RAM when its needed,

The more RAM the less swopping is required,

A computer crashes when the processor is too busy swopping rather than carrying out processing instructions.

Standard Name

Memory Clock (MHz)

I/O Bus Clock (MHz)

Data Transfer Rate (MHz)

Module Name

Peak Transfer Rate (MB/s)

DDR-200 100 100 200 PC-1600 1600

DDR-266 133 133 266 PC-2100 2100

DDR-333 166 166 333 PC-2700 2700

DDR-400 200 200 400 PC-3200 3200

DIMMS – Dual In-Line Memory Module

SDRAM – Synchronous Dynamic Random Access

Memory

Types of RAM

DDR – Double Data Rate

168pin SDRAM DIMMS – have a double notch (PC100, PC133) - obsolete

184pin DDR SDRAM DIMMS - have a single notch in the middle – old machines

240pin DDR2 DIMMS – have a single notch in the middle first available 2003

Standard Name

Memory Clock

I/O Bus Clock

Data Transfer Rate Module Name

Peak Transfer Rate

DDR2-400 100 MHz 200 MHz 400 Million PC2-3200 3200 MB/s

DDR2-533 133 MHz 266 MHz 533 MillionPC2-4200PC2-43001 4266 MB/s

DDR2-667 166 MHz 333 MHz 667 MillionPC2-5300PC2-54001 5333 MB/s

DDR2-800 200 MHz 400 MHz 800 Million PC2-6400 6400 MB/s

DDR2-1066 266 MHz 533 MHz 1066 MillionPC2-8500PC2-86001 8533 MB/s

240pin DDR3 DIMMS – have a single notch different place to DDR2, first available 2007, frequently have a heat sink,

Standard Name

Memory Clock

I/O Bus Clock

Data Transfer Rate Module Name

Peak Transfer Rate

DDR3-800 100 MHz 400 MHz 800 MT/s PC3-6400 6400 MB/s

DDR3-1066 133 MHz 533 MHz 1066 MT/s PC3-8500 8533 MB/s

DDR3-1333 166 MHz 667 MHz 1333 MT/s PC3-10600 10667 MB/s

DDR3-1600 200 MHz 800 MHz 1600 MT/s PC3-12800 12800 MB/s

When buying RAM need to ensure that motherboard is compatible and supports the clock speed

Properties RAM

Make Model Capacity Type of RAM Socket type Speed – (Memory Clock / IO Bus Clock / Data Transfer Rate)

Cache Another type of memory is cache – this is like a

temporary holding area for data between components that may operate at different speeds,

Typically we find cache on processors and DVD burners,

Processors have L1 and L2 cache (L1 being the closest to the processor).

BTEC Book – Unit 02 p10 /11 (start at the Internal Memory heading)

Extra Task In your own words explain the function of random access memory in a

typical modern personal computer. The function means what its main job is. Include details of the different

types available.Remember explain means to give a detailed account of something with

reasons – include how it works, and why its required.