PC Hardware

Grade 9

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…

Four Primary Functions of a Computer

• Input

• Process

• Output

• Store

Types of Computers

• Supercomputer

• Server

• Embedded Computer

• Personal Computer

Supercomputer

Server

Embedded Computers

Personal Computers (PCs)

Types of PCs

• Desktop

• Laptop

• PDA

• Tablet PC

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

Sample Classification

How are humans like a computer?

• Input devices?• Output devices?• Processing devices?• Storage devices?

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 human computer

Output Output

Input

Long Term Storage! Short Term Memory!

Processing Information

Typical Desktop PC Hardware

• Central Processing Unit (CPU)• Motherboard• Random Access Memory (RAM) modules• Hard Drive• Keyboard• Mouse• Monitor• Power supply, case, etc.

Typical Desktop PC Hardware

Computer Part• CPU• Motherboard• RAM modules• Hard Drive• Keyboard• Mouse• Monitor• Power supply, case, etc.

Category• Processing device• Processing device• Storage/Processing device• Storage device• Input device• Input device• Output device• N/A

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.

A closer look at a motherboard…

Ports

Motherboard

Evaluating a computer

• SpeedSpeed– How fast can my PC process information?

• Memory CapacityMemory Capacity– How many programs can my PC use at once?

• Storage CapacityStorage Capacity– How many files can my PC save?

• Other components:Other components:– Can I watch DVDs? Can I play video games? Can I

connect my MP3 player?

Evaluating a computer

• SpeedSpeed– CPU speed

• Memory CapacityMemory Capacity– RAM size

• Storage CapacityStorage Capacity– Hard Drive size

• Other components:Other components:– Ex: Floppy drive, CD-ROM, DVD-RAM, video card,

USB ports

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

CPU

InputO

utput

Each cycle this process repeats!

The CPU The CPU cycle:cycle:

Before we talk about memory:

• ROM vs RAMROM 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 NonvolatileVolatile vs Nonvolatile– Volatile = Memory is lost if power goes out– Nonvolatile = Memory is more permanent

How much is a byte?

Name Abbr. Num. Bytes Relative SizeByte B 1 byte 1 character

Kilobyte KB 1,024 bytes ¼ typed pageMegabyte MB 1,048,576 bytes 768 pagesGigabyte GB 1,073,741,824B 786,432 pages

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

Storage Capacity

Medium Capabilities Capacity

Hard Drive RAM External: up to 2TBInternal: up to 500GB

CD / CD-RW ROM / RAM 700MB

DVD/DVD+RW ROM / RAM 4.7GB to 9.4GB

Flash Cards RAM 16MB to 8GB

Floppy Disk RAM 1.44MB

Flash Drive RAM Up to 6GB

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.