1. Unit 2: Computer Systems
Session One Part One

2. Aims: Discussion into what will be covered in this unit. Assessment
Understand the basic principles
Gain an understanding into the system components
Power supply
Motherboard
Chipsets
Processor
Cache Memory
(Continued on Part 2)

3. What is covered? Computer components Recommend computer systems
Internal system unit components
Peripherals
Backing storage
Operating system software
Software utilities
Recommend computer systems
Organisational requirements

4. What is covered? Set up and maintain computer systems
Install hardware and software
PC Configuration
Testing
Maintenance

5. How will you be assessed?
One Assignment
Practical observations within a system support lab

6. Basic Principles CPU Can you name any other input and output devices?
Central Processing Unit
Input device
Output device
keyboard
mouse
microphone
screen
printer
speaker
Can you name any other input and output devices?

7. Central Processing Unit
Basic Principles
Input devices
CPU
Central Processing Unit
Input device
Output device
Input devices
Capture information from the real world
Send data to the CPU

8. Central Processing Unit
Basic Principles
Output devices
CPU
Central Processing Unit
Input device
Output device
Output devices
Are sent data by the CPU
Convert the data to an understandable form, e.g. images on screen, sounds, printed text

9. Central Processing Unit
Basic Principles
Where is data stored
Hard disk
USB device CD
DVD
CPU
Central Processing Unit
Input device
Output device
Main memory
Backing store
RAM

10. Basic Principles How is data stored
All computer data is stored as binary patterns.
Binary patterns are combinations of 1s and 0s, e.g
Each 1 or 0 is known as a bit.
Binary patterns are usually stored in groups of 8, 16, 24, 32 or 64 bits.

11. Basic Principles What is data What is information?
Data is unorganised facts, numbers, letters and symbols represented in a formalised manner suitable for communication, interpretation and processing by computers. (Binary code)
What is information?
Information is data which has been assigned a commonly understood meaning. (Human understanding)

12. System components Power Motherboard Chipsets The Processor
System Memory
Video Cards
System Case
Monitors
Hard Disk Drives
CD-ROM Drives

13. Power http://computer.howstuffworks.com/power-supply.htm
The power supply converts the alternating current (AC) line from your home to the direct current (DC) needed by the personal computer.
Power supplies, often referred to as "switching power supplies", use switcher technology to convert the AC input to lower DC voltages. The typical voltages supplied are:
3.3 volts
5 volts
12 volts
The 3.3- and 5-volts are typically used by digital circuits, while the 12-volt is used to run motors in disk drives and fans. The main specification of a power supply is in watts. A watt is the product of the voltage in volts and the current in amps

14. Motherboard
This is the main circuit board that all of the other internal components connect to.
The CPU and memory are usually on the motherboard. Other systems may be found directly on the motherboard or connected to it through a secondary connection.
For example, a sound card can be built into the motherboard or connected through PCI (Peripheral Component Interface) or a graphics card connected via the AGP (Accelerated Graphics Port)

15. Motherboard Continued
The most important thing to remember about the motherboard is that it is a printed circuit board which provides all the connections, pathways and "lines" connecting the different components of the computer to each other - specifically, the Central Processing Unit or CPU, which is where (as its name implies) all the "processing" is going on to everything else.

16. Chipsets
A set of chips that provides the interfaces between all of the PC's subsystems. It provides the buses and electronics to allow the CPU, memory and input/output devices to interact.
The most important connections are to the chipsets - especially the Northbridge chipset which is connected to the main computer memory (hard disk and RAM), while the Southbridge set is connected to the peripherals - video and audio cards, IDE controllers, etc.
IDE stands for "Integrated Drive Electronics" ATA stands for "Advanced Technology Attachment" PATA stands for "Parallel Advanced Technology Attachment" SATA stands for "Serial Advanced Technology Attachment“
AGP stands for “Accelerated Graphics Port”

17. Processor
A CPU - also known as a microprocessor - is a complete computation engine that is fabricated on a single chip. Often referred to as the brain of the computer.

18. Processor Continued
Controls the transmission of data from input devices to memory
Processes the data held in main memory
Controls the transmission of information from main memory to output devices

19. Processor Continued
The CPU uses its ALU (Arithmetic Logic Unit) to enable it to perform mathematical operations like addition, subtraction, multiplication and division.
Modern CPUs contain complete floating point processors that can perform extremely sophisticated operations on large floating point numbers.
A CPU can move data from one memory location to another.
A CPU can make decisions and jump to a new set of instructions based on those decisions.

20. Processor Continued CPU – fetch-decode execute cycle
The fundamental operation of most CPUs, regardless of the physical form they take, is to execute a sequence of stored instructions called a program. This is achieved by using the fetch-decode and execute cycle.

21. Processor Continued Fetch
Fetch involves retrieving an instruction from program memory.
The location in program memory is determined by a program counter (PC), the program counter keeps track of the CPU's place in the current program. Often the instruction to be fetched must be retrieved from relatively slow memory, causing the CPU to stall while waiting for the instruction to be returned. This issue is largely addressed in modern processors by caches.

22. Processor Continued Decode
The instruction that the CPU fetches from memory is used to determine what the CPU is to do. In the decode step, the instruction is broken up into parts that have significance to other portions of the CPU.
The way in which the numerical instruction value is interpreted is defined by the CPU's instruction set architecture (ISA).
Often, one group of numbers in the instruction, called the opcode, indicates which operation to perform. The remaining parts of the number usually provide information required for that instruction, such as operands for an addition operation.

23. Processor Continued Execute
During this step, various portions of the CPU are connected so they can perform the desired operation. If, for instance, an addition operation was requested, an arithmetic logic unit (ALU) will be connected to a set of inputs and a set of outputs. The inputs provide the numbers to be added, and the outputs will contain the final sum.

24. Types of CPU
Intel and Advanced Micro Devices (AMD) lead the market in terms of speed and quality.
Intel's desktop CPUs include Celeron, Pentium, and Core.
AMD's desktop processors include Sempron, Athlon, and Phenom.

25. Cache Memory CPU – Cache Memory
high-speed memory used as a temporary store for recently processed instructions and data, or those which the CPU predicts will be processed soon
Much quicker to access instructions and data from cache memory than requesting it from normal RAM
Two types of cache exist, Level 2 (L2) and Level 1 (L1)
L2 cache can be on the motherboard, located between the CPU and RAM
L1 cache is part of the CPU itself.
Cache memory is typically very expensive, so would be prohibitive in great quantities.

26. Types of CPU continued
Getting a processor with a dual, triple, or quad core can make a significant difference in the processing power of your computer.
It's like having two, three, or four separate processors installed on your computer at one time.
These processors work together to make your computer multitask faster and with greater efficiency. Getting a CPU with a larger front side bus can enhance the processor's ability to communicate with RAM, which will increase your computer's overall speed.

27. Conclusion: Discussed what will be covered in this unit
Outlined the Assessment strategy
Demonstrated some Understanding into the basic principles
Gained an understanding into the system components
Power supply
Motherboard
Chipsets
Processor
Cache Memory
(Continued on Part 2)