GCSE Lesson - Hardware

1. Hardware

2. Central Processing Unit (CPU)
• The hardware that executes the programs and manages the rest of the
hardware.

3. Executing a Program
• Initially the program is loaded into the main memory.

4. Fetch Execute Cycle
=
Average processor speed of a PC is 3 - 4GHz.

5. CPU Performance
• In order to increase the performance cache can be used.
• Cache is a memory that can store frequently used instructions or
data.(4MB average size of a cache)

6. Purpose of CPU
• fetch instructions from main memory
• fetch data from main memory
• decode the instructions
• execute the instructions
• perform calculations
• manage the movement of instructions and data to and from peripheral devices

7. Multi Core Processors
• Dual core has two processors.
• Quad core has four processors.
• Multi core processors work on different programs and work faster than a single core
processor.

8. Memory
• A component used to store data.
• There are different types of memories for different purposes.
• Eg: RAM, Memory Stick

9. RAM – Random Access Memory
• Random refers to the fact that you can write anywhere in that memory space at any
time.
• Volatile
• The main purpose of the RAM is to act as temporary storage for programs and
data.

10. Virtual Memory
• Configuring hard disk to behave as RAM is called Virtual Memory.
• Used to store parts of the program currently being run but actually being executed
has to be sorted in RAM.
• As the program proceeds, sections are swapped between the RAM and the Virtual
memory.

11. ROM - Read Only Memory
• Non-volatile.
• Cannot write over the contents
• It has the bootstrap loader to start the machine.

12. Secondary Memory
• These long term, non volatile types of storage are also called Secondary Memory.
• Eg: Hard Drive, Memory Stick, CD, DVD.
• Much larger compared to primary storages.
• Cheaper memory technologies tend to have slow access speeds.
• Should be robust and reliable.

13. What you need to consider when
choosing a secondary memory
• Capacity- how much space is available?
• Speed- how quickly the data can be read and stored?
• Portability- can you easily unplug it and carry away easily?
• Durability- how easily is it damaged?
• Reliability- how long will it last?

14. Storage technologies
• Magnetic
– Oldest technology used. Eg: floppy disk, hard disk, tapes
– Cheap and high capacity
– Magnetic disks are read with a moving head
– Magnetic tapes are read by moving the tape fast a read-write head
– Vulnerable to damage
– Moving parts go wrong often

16. Storage technologies
• Optical
– Lasers write data to the disc and read
data from it
– CD, DVD

17. Storage technologies
• Solid State
– A type of a RAM
– Non-volatile type of RAM
– Access speed is slow compared to RAM
– Used in Tablets, Mobile Phones

19. Input Devices
• Keyboard
• Mouse (laser or tracker ball)
• Touch Screen
• Barcode Scanner
• OMR- Optical Mark Recognition (lottery tickets)
• OCR- Optical Character Recognition
• Joystick
• Microphone
• Sensors
• Camera
• Sip and Puff switches

20. Output Devices
• CRT – cathode ray tube
• LCD- Liquid Crystal Display
• TFT – Thin Film Transistor
• Speakers
• Inkjet Printer
• Laser Printer
• Actuators
• Lights

21. Appropriate I/O Devices

22. Appropriate I/O Devices

23. Appropriate I/O Devices

24. Logic Gates