Mr C Johnston ICT Teacher 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 – SATA 1 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 – SATA 2 HDD DVD-RW Motherboard SATA 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.

Peripherals 1 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”.

Peripherals 2 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:

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 NamePeak Transfer Rate (MB/s) DDR PC DDR PC DDR PC DDR PC 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 DDR MHz200 MHz400 MillionPC MB/s DDR MHz266 MHz533 Million PC PC MB/s DDR MHz333 MHz667 Million PC PC MB/s DDR MHz400 MHz800 MillionPC MB/s DDR MHz533 MHz1066 Million PC PC 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 DDR MHz400 MHz800 MT/sPC MB/s DDR MHz533 MHz1066 MT/sPC MB/s DDR MHz667 MHz1333 MT/sPC MB/s DDR MHz800 MHz1600 MT/sPC 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.