-> Computer - an electronic device operating under the control of instructions stored in its own memory that can accept, manipulate, and store data
-> Hardware components
* Central processing unit (CPU)
* Primary storage
* Secondary storage
* Input device
* Output device
* Communication device
Central Processing Unit
-> Central processing unit (CPU) (or microprocessor) - the actual hardware that interprets and executes the program (software) instructions and coordinates how all the other hardware devices work together
-> Control unit - interprets software instructions and literally tells the other hardware devices what to do, based on the software instructions
-> Arithmetic-logic unit (ALU) - performs all arithmetic operations (for example, addition and subtraction) and all logic operations (such as sorting and comparing numbers)
-> The number of CPU cycles per second determines the speed of a CPU
* Megahertz (MHz) - the number of millions of CPU cycles per second
* Gigahertz (GHz) - the number of billions of CPU cycles per second
-> CPU speed factors
* Clock speed
* Word length
* Bus width
* Chip line width
-> Binary digit (bit) - the smallest unit of information that a computer can process
-> Byte - a group of eight bits representing one natural language character
Primary Storage
-> Primary storage - the computer’s main memory, which consists of the
random access memory (RAM), cache memory, and the read-only memory (ROM) that is
directly accessible to the CPU
RANDOM ACCESS MEMORY (RAM)
-> Random access memory (RAM) - the computer’s primary working memory, in
which program instructions and data are stored so that they can be accessed
directly by the CPU via the processor’s high-speed external data bus
* Volatility
* Cache memory
READ ONLY MEMORY (ROM)
-> Read-only memory (ROM) - the portion of a computer’s primary storage that
does not lose its contents when one switches off the power
* Flash memory
* Memory card
* Memory stick
Secondary Storage
-> Secondary storage - consists of equipment designed to store large volumes of
data for long-term storage
* Megabyte (MB or M or Meg) - roughly 1 million bytes
* Gigabyte (GB) - roughly 1 billion bytes
* Terabyte (TB) - roughly 1 trillion bytes
Magnetic Medium
-> Magnetic medium - a secondary storage medium that uses magnetic techniques to store and retrieve data on disks or tapes coated with magnetically sensitive materials
-> Magnetic tape - an older secondary storage medium that uses a strip of thin plastic coated with a magnetically sensitive recording medium
-> Hard drive - a secondary storage medium that uses several rigid disks coated with a magnetically sensitive material and housed together with the recording heads in a hermetically sealed mechanism
Optical Medium
-> Optical medium types include:
+ Compact disk-read-only memory (CD-ROM)
+ Compact disk-read-write (CD-RW) drive
+ Digital video disk (DVD)
+ DVD-ROM drive
+ Digital video disk-read/write (DVD-RW)
INPUT DEVICES
-> Input device - equipment used to capture information and commands
1. Manual input device
- Joystick
- Keyboard
- Microphone
- Bar code scanner
- Digital camera
- Magnetic ink character reader
OUTPUT DEVICE
-> Output device - equipment used to see, hear, or otherwise accept the results of information processing requests
- Cathode-ray tube (CRT)
- Liquid crystal display (LCD)
- Laser printer
- Ink-jet printer
- Plotter
Communication Device
-> Communication device - equipment used to send information and receive it from one location to another
Dial-up access
Cable
Digital subscriber line
Wireless
Satellite
