1. PC Hardware Grade 9 The difference between hardware and software.
Hardware is physically hard. You can touch it.
Software can’t be touched. It is the programs or applications that are executed on the hardware machine.

2. PC Hardware Outline What is a computer?
What are examples of computers?
What types of PCs exist?
What is the typical PC hardware?
How might we evaluate a PC?
In terms of Speed…
In terms of Storage Capacity…
In terms of Memory…

3. Four Primary Functions of a Computer
Input
Process
Output
Store
These are each done to data or information.
A calculator is a computer that takes numbers and operations as input “2+2”
It then processes “2+2” by adding the numbers 2 and 2 together
It then outputs the result “4” to its display
Using the memory key (M) on a calculator we can store the result for future calculations
These functions are common among computers, but primarily the “Process” function is the only function guaranteed to be present in a computer.
Some computers can not store information for the future. And many computers may not take an input or output that is apparent to its user.

4. Types of Computers Supercomputer Server Embedded Computer
Personal Computer
We are really only concerned with personal computers and distinguishing them from other types computers.
See the definition in the introductory slides for a definition of Personal Computer.
I will give examples of Supercomputer, Server, and Embedded computers on the next few slides.

5. Supercomputer
Typically used for large scale scientific and mathematical calculations. Very expensive to build. Contains thousands of CPUs.
Can’t run Solitaire much faster than your PC.
The reason this is fast for scientific calculations is that we can do many calculations at once. For instance, we can add 1000s of numbers at once instead of one after another. However, the solitaire card game does not require 1000s of additions to take place at one time, so its program instructions do not execute any faster when one is executed before another.

6. Server
A server is special because it is meant to SERVE many clients quickly.
The wires shown here connect this server to many clients. The server actually contains several fast, expensive, powerful computers that take turns helping new clients.

7. Embedded Computers
Embedded computers are everywhere in our lives. Think about how the computers in these devices complete the functions of input, output, processing, and storage.

8. Personal Computers (PCs)

9. Types of PCs Desktop Laptop PDA Tablet PC
These all contain very similar hardware that fulfills very similar functions, except the hardware has been customized to the size and purpose of the device.
For instance a laptop is smaller than a Desktop but nearly as powerful. A PDA is much smaller than a laptop, but lacks in processing power and memory.
Generally smaller technology is newer and more expensive.

10. Computer Hardware
Computer hardware can be classified in relation to the four primary functions of a computer (discussed earlier):
Input devices
Output devices
Processing devices
Storage devices
A device may fit in more than one category.
RAM is memory used to store data while processing it. Thus you might label the RAM a storage device or processing device because it is used both during storage and processing of information.

11. Sample Classification

12. How are humans like a computer?
Input devices?
Output devices?
Processing devices?
Storage devices?

13. How are humans like a computer?
Input devices?
Hands, Ears, Eyes, Nose, (Our senses)
Output devices?
Mouth, Hands, (Talking, writing, typing, etc)
Processing?
Brain
Storage?
Short term memory
Long term storage
The personal computer has similar parts. It also has a short and long term memory. (RAM vs. Hard Disk)

14. The human computer Input Long Term Storage! Short Term Memory!
Processing Information
Input
Unless this reminds you of our in class discussion, do not try to interpret it.
Output Output

15. Typical Desktop PC Hardware
Central Processing Unit (CPU)
Motherboard
Random Access Memory (RAM) modules
Hard Drive
Keyboard
Mouse
Monitor
Power supply, case, etc.
These are the typical components of a Desktop
Other devices that can be attached but are not essential are called “peripherals”

16. Typical Desktop PC Hardware
Computer Part
Category
CPU
Motherboard
RAM modules
Hard Drive
Keyboard
Mouse
Monitor
Power supply, case, etc.
Processing device
Storage/Processing device
Storage device
Input device
Output device
N/A
These are the typical components of a Desktop PC
A device may fit in more than one category.
RAM is memory used to store data while processing it. Thus you might label the RAM a storage device or processing device because it is used both during storage and processing of information.

17. Consider editing a document on a PC
When you type a letter on the keyboard, it is sent to the CPU as input.
Your input travels through the motherboard and is stored in RAM. The RAM is short-term memory that holds programs and data you are using.
The CPU processes your input as a document character and updates the output on the monitor to show the new character that you typed.
Finally, when you save the document the information is stored for the long term on the hard disk drive.
This is a simplified view, but hopefully you can think logically about the path of your input, how it is processed, how it is output or stored by the PC, and which hardware devices do those operations.

18. A closer look at a motherboard…
Notice this PC motherboard can be expanded to include new hardware or more memory. Laptops are not as easily expanded.
Also note the ports available to connect peripherals, such as the two USB ports.
Ports

19. Evaluating a computer Speed Memory Capacity Storage Capacity
How fast can my PC process information?
Memory Capacity
How many programs can my PC use at once?
Storage Capacity
How many files can my PC save?
Other components:
Can I watch DVDs? Can I play video games? Can I connect my MP3 player?
These are the types of questions we might ask.
Many software and hardware devices have a list of “minimum system requirements” that help you answer these questions.

20. Evaluating a computer Speed Memory Capacity Storage Capacity
CPU speed
Memory Capacity
RAM size
Storage Capacity
Hard Drive size
Other components:
Ex: Floppy drive, CD-ROM, DVD-RAM, video card, USB ports
These are the measurements that can help answer our question.

21. CPU speed Measured in Hz (Cycles per second)
CPU processes data during each cycle
Early PCs ran at speeds such as 2MHz or 2,000,000 cycles per second:
1 Hz = 1 cycle per second
1 MHz = 1,000,000 Hz
1 GHz = 1,000 MHz or 1,000,000,000 Hz
Modern PC CPUs are typically between 1GHz and 3GHz
CPU speed grows quickly.
That does not necessarily mean faster computer.
Sports car analogy.

22. Each cycle this process repeats!
CPU speed
Input
CPU
The CPU cycle:
Information can be stored between cycles in a different part of the computer.
The faster a cycle can be completed, the faster information can be processed.
Each cycle this process repeats!
Output

23. Before we talk about memory:
ROM vs RAM
ROM = Read Only Memory
Can only read contents, can’t write them
RAM = Random Access Memory
Can read or write to memory
Volatile vs Nonvolatile
Volatile = Memory is lost if power goes out
Nonvolatile = Memory is more permanent
Memory can typically be classified to have one of each of these properties.

24. How much is a byte? Name Abbr. Num. Bytes Relative Size Byte B 1 byte
1 character
Kilobyte KB
1,024 bytes
¼ typed page
Megabyte MB
1,048,576 bytes
768 pages
Gigabyte GB
1,073,741,824B
786,432 pages
Things whose size you might measure with each of them:
Byte = characters
KB = documents
MB = MP3s, videos, documents, small programs
GB = Large programs, Big movies

25. Storage Capacity
In these slides I’m referring to the Long Term storage of a computer.
This is the memory used to store files and programs for future use.
In PCs, the internal hard drive is typically used for long term storage.
More Hard Drive space = More files you can store
Long term storage is non-volatile. (Still there after the power goes out)

26. Storage Capacity Medium Capabilities Capacity Hard Drive RAM
External: up to 2TB Internal: up to 500GB
CD / CD-RW
ROM / RAM
700MB
DVD/DVD+RW
4.7GB to 9.4GB
Flash Cards
16MB to 8GB
Floppy Disk
1.44MB
Flash Drive
Up to 6GB
When I say “Storage Capacity,” I mean “Long Term Storage”
ROM = Read Only Memory RAM = Random Access Memory (Read and Write are possible)
[Table is an estimate as of 2006]

27. Memory Capacity
In these slides I’m referring to the Short Term storage of a computer.
This is the memory used to hold programs and data while your computer is running.
In PCs, the RAM is typically used for short term storage.
More RAM space = More programs you can run at once.
When I say “Memory Capacity,” I mean short term memory capacity.
Short term memory is volatile. (Gone when the power goes off)