1. An Introduction to
The computer

2. Computer
a machine that
follows instructions
to accomplish a task

3. HARDWARE SOFTWARE Any physical components of a computer
Any instructions followed by the computer

4. Categories of hardware
Processor (CPU)
Memory (Primary Storage) "RAM"
Secondary Storage
Input & Output (Human/Computer Interaction)
Communications (with other computers and devices)

5. Categories of hardware
PROCESSOR (CPU)
Controls all other hardware components
Executes (follows) simple instructions
Arithmetic: + - X ÷ (sometimes more: sin() cos())
Relational: < > =
Logical: and or not
Move (Copy) very small units of data/instructions
Holds only a few small units of data/instructions

6. Categories of hardware
MEMORY (Primary Storage)
Short Term / Temporary storage of data and instructions currently in use.
Organization: set of Locations, where each Location:
stores one instruction or a small unit of data (Contents)
has a numeric Address
Data/instructions must be in memory for the CPU to use it
Volatile: contents lost when power is lost

7. Categories of hardware
SECONDARY STORAGE
Long term storage of data and instructions
Organization: similar to Memory (Locations)
Non-Volatile: information “saved” without power
Larger than Memory (more Locations)
Slower access by CPU (must be copied to Memory)
Ex: Hard Drive, Thumb Drive, DVD, CD, Tape

8. Categories of hardware
INPUT & OUTPUT
Allows the computer to interact with a human
Input: allows the human to enter information into the computer (ex: mouse, keyboard, microphone, scanner, camera).
Output: allows the computer to deliver information to a human (ex: monitor, speaker, printer)

9. Categories of hardware
COMMUNICATIONS
Allows the computer to send/receive data to/from other computers and devices.
May be wired (NIC: Network Interface Card, modem) or wireless (Bluetooth, cellular)

10. Basic diagram of a computer

11. ALL data and instructions are stored in terms of two digits: 1 & 0
Digital information
ALL data and instructions are stored in terms of two digits: 1 & 0
Why? For the engineers:
an “on/off switch” is the simplest machine component.
a machine that constantly transforms itself is most easily built from the simplest components.

12. Physical Representation
Digital information
Physical Representation
Volatile hardware: electricity is On or Off
Non-Volatile hardware: depends on the physical medium. Ex:
Hard drive: magnetic (attract or repel)
DVD: laser reflection (reflects or does not reflect)

13. Units of measure Processor
Cycle: a single action of a CPU; single "clock tick"
Fetch: copy an instruction from memory
Execute: follow/carry out an instruction
Hertz: cycles per second
Kilohertz: 1,000 cycles per second
Megahertz: 1,000 kilohertz

14. Units of measure Storage Bit – a single digit (1 or 0) Byte – 8 bits
Kilobyte – 1,000 bytes (previous: 1,024 bytes)
Megabyte – 1,000 kilobytes (prev: 1,024 KB)
Gigabyte – 1,000 megabytes (prev: 1,024 MB)

15. Units of measure Storage Word – the size of a memory location
unit of data used by most computer operations
size varies by computer model (1,2,4,8,etc. bytes)
Ex: in a 64-bit machine, a Word is 8 bytes.

16. categories of software
Application
Performs a particular task
(Ex: mail, game, word processor, internet browser)
Application Support
Utilities used by multiple applications
(Ex: MS .Net, Java Runtime Environment)
Systems
Operating System: Control of Hardware, User Interface & App Services
(Ex: MacOS, MS-Windows, Linux)

17. Vocabulary Summary Term Definition Computer
A machine that follows instructions to accomplish a task
Hardware
Any physical components of a computer.
Software
Any instructions followed by the computer.
Processor
Computer hardware category that controls all other hardware and follows (executes) the instructions.
Memory
Short term/temporary storage of data and instructions currently in use.
Location
An individual element of memory, it stores one instruction or one small piece of information. It has an Address and Contents.
Volatile:
Describes hardware where information is lost when electricity is lost.
Secondary Storage
Long term, non-volatile storage if information. It is larger but slower for the CPU to access information stored here as compared to Memory. Ex: hard drive, thumb drive, DVD.
Input/Output
Category of hardware that allows the computer to interact with a human. Ex: Keyboard, Mouse, Monitor, Speaker.
Communications
Category of hardware that allows the computer to share information with other computers and devices.
Hertz
A unit of measure of the processor, meaning 1 cycle per second.

18. Vocabulary Summary Term Definition Kilohertz 1,000 hertz Megahertz
Bit
A single binary digit (1 or 1)
Byte
8 bits
Kilobyte
1,024 bytes
Megabyte
1,024 kilobytes
Gigabyte
1,024 megabytes
Word
The size of a memory location expressed in bytes. The exact number varies by CPU model.
Application
Software that performs a particular task. (Ex: , game, word processor)
Application Support
Software consisting of utilities shared by multiple applications (Ex: MS .Net, Java JRE).
Operating System
Software that controls the hardware, provides an interface for the user to command the computer to perform tasks, and provides services for applications.