Mr C Johnston ICT Teacher computechedu.co.uk

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

2. 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.

3. 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)

4. 4x SATA Channels 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

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

6. 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)

7. 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.

8. 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”.

9. 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.

10. 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

11. 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.

12. BTEC Book – Unit 02 p8 - 10

13. 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.

14. 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.

15. 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.

16. Types of RAM • 168pin SDRAM DIMMS – have a double notch (PC100, PC133) - obsolete • 184pin DDR SDRAM DIMMS - have a single notch in the middle – old machines SDRAM – Synchronous Dynamic Random Access Memory DIMMS – Dual In-Line Memory Module DDR – Double Data Rate

17. 240pin DDR2 DIMMS – have a single notch in the middle first available 2003 • 240pin DDR3 DIMMS – have a single notch different place to DDR2, first available 2007, frequently have a heat sink, • When buying RAM need to ensure that motherboard is compatible and supports the clock speed

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

19. 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).

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

21. Extra Task • In your own words explain the function of random access memoryin 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.