Mr C Johnston ICT Teacher www.computechedu.co.uk BTEC IT Unit 02 - Lesson 03 Inside Computers #2 – Drives, Connectors and Internal Memory Mr C Johnston ICT Teacher www.computechedu.co.uk

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 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!! IDE Cable SATA Cable 4x SATA Channels

Hard Drive Controllers – SATA2 HDD Drive data and power cables DVD-RW Motherboard SATA connections

Connect 2 hard disk drives and a DVD Rom drive correctly to a mother board using SATA connections BTEC Book – Unit 02 p7 (start at the Hard drive configuration and controllers heading)

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

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.

Types of RAM SDRAM – Synchronous Dynamic Random Access Memory DIMMS – Dual In-Line Memory Module 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 Standard Name Memory Clock (MHz) I/O Bus Clock (MHz) Data Transfer Rate (MHz) Module Name Peak Transfer Rate (MB/s) DDR-200 100 200 PC-1600 1600 DDR-266 133 266 PC-2100 2100 DDR-333 166 333 PC-2700 2700 DDR-400 400 PC-3200 3200

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 Million PC2-4200 PC2-43001 4266 MB/s DDR2-667 166 MHz 333 MHz 667 Million PC2-5300 PC2-54001 5333 MB/s DDR2-800 400 MHz 800 Million PC2-6400 6400 MB/s DDR2-1066 533 MHz 1066 Million PC2-8500 PC2-86001 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.