Chapter 2 Hardware Basics: Inside the Box

Basic Functions of a Computer

ü  Receive input: Accept information from the outside world

ü  Process information: Perform arithmetic or logical (decision-making) operations on information

ü  Produce output: Communicate information to the outside world

ü  Store information: Move and store information in memory

Basic Components of a Computer

ü  Input devices

Ø  Keyboards and pointing devices
(mouse)

ü  Output devices

Ø  Display or video monitor

Ø  Printer

Ø  Speakers

ü  Central Processing Unit (CPU)

Memory and storage devices

Ø  Primary storage: RAM (Random Access Memory)

Ø  Secondary storage: Storage devices that serve as
long-term repositories for data:

ü  Hard disk drives

ü  Recordable CD and DVD drives

ü  Tape drives

Computer’s information is digital

Ø   Bit, or binary digit

q  The smallest unit of information

q  Can have one of two values: 1 or 0

q  Can represent numbers, codes, or

    instructions

Ø   Byte: a collection of 8 bits

Bits, Bytes, and Buzzwords

Bit-related terminology

Byte	8 bits
Kilobyte (KB)	1  Thousand Bytes
Megabytes (MB)	1 Million Bytes
Gigabytes (GB)	1 Billion Bytes
Terabytes (TB)	1 Trillion Bytes

CPU (microprocessor)

Ø  Communicates with all the other parts of the computer system indirectly through memory

Ø  An extraordinarily complex collection of electronic circuits

Ø  Housed along with other chips and electronic components on the motherboard

RAM (random access memory)

Ø  Used to store program instructions and data temporarily

Ø  Unique addresses and data can be stored in any location

Ø  Can quickly retrieve information

Ø  Will not remain if power goes off  (volatile)

ROM (read-only memory)

Ø  Information stored permanently on a chip

Ø  Contains startup instructions and other permanent data

CMOS (complementary metal oxide   semiconductor)

Ø  Special low-energy kind of RAM 

Flash memory

Ø  Used for phones, pagers, portable computers, handheld computers, and PDAs

Buses

ü  Typically have 32 or 64 wires

ü  Connect to storage devices in bays

ü  Connect to expansion slots

ü  Connect to external buses and ports

Slots and ports

ü  Make it easy to add external devices, called peripherals.       

The CPU uses:

Ø  RAM (random access memory) as a temporary storage area—a scratch pad—for instructions and data

Ø  ROM (read-only memory), which contains unchangeable information that serves as reference material for the CPU as it executes program instructions

The CPU and main memory are housed in silicon chips on the motherboard.