CSCI N241 Web Design: The Essentials of Computing
1. GOALS
Recognize simple tasks computers perform Become familiar with characteristics and capabilities of processing units Distinguish between analog and digital storage Describe the fetch/execute cycle Be able to classify encoding schemes

CSCI N241 Web Design: The Essentials of Computing
2. What is a COMPUTER?
A Computer is the Universal Information Manipulator

CSCI N241 Web Design: The Essentials of Computing
3. What is INFORMATION?
Examples: numbers, words, instructions INFORMATION is also referred to as DATA. Two most important ways to store data - DIGITAL information storage ANALOG information storage

CSCI N241 Web Design: The Essentials of Computing
4. ANALOG Information Storage
Analog - An information coding scheme based on physical analogies between a value and some physical object. Analog information is MECHANICAL. Characterized by INFINITE precision but LIMITED accuracy. Example: Mercury Thermometer

CSCI N241 Web Design: The Essentials of Computing
5. DIGITAL Information Storage
Digital - An information coding scheme based on numeric representation of values. Digital devices record information as a series of NUMBERS then translate the numbers to represent another entity. Characterized by LIMITED precision but STRONG accuracy.

CSCI N241 Web Design: The Essentials of Computing
6. Characteristics of DIGITAL COMPUTERS
Limited precision but extreme accuracy Manipulates numbers Makes number represent various other kinds of information

CSCI N241 Web Design: The Essentials of Computing
7. Binary Storage
A computer is a machine dealing with ELECTRONIC impulses Voltage is an analog property, but forcing circuitry to accept it as one of two values make the computer a digital system. Values recognized are high and low - sometimes referred to as on/off, true/false or yes/no. Binary notation - 1's and 0's

CSCI N241 Web Design: The Essentials of Computing
8. Binary Lightswitch Demo
Binary Tutorial

CSCI N241 Web Design: The Essentials of Computing
9. The Binary System
Binary Numbering System Decimal Binary 2^3 (8s) 2^2 (4s) 2^1 (2s) 2^0 (1s) 0 0 0 0 0 0 1 1 0 0 0 1 2 10 0 0 1 0 3 11 0 0 1 1 ... ... ... ... ... ... 8 1000 1 0 0 0

CSCI N241 Web Design: The Essentials of Computing
10. Converting Binary to Decimal
Converting Binary to Decimal Convert 1001 to Decimal Place Value 8 4 2 1 Binary Value 1 0 0 1 Decimal Value 8 0 0 1 Answer = 9 CAN YOU CONVERT 1101 TO A DECIMAL VALUE?

CSCI N241 Web Design: The Essentials of Computing
11. Converting Decimal to Binary
Converting Decimal to Binary Convert 13 to Binary Place Value 16 8 4 2 1 Binary Value - 1 1 0 1 Decimal Value - - - - - HOW DO YOU CHECK YOUR ANSWER?

CSCI N241 Web Design: The Essentials of Computing
12. Binary and Other Kinds of Information
Whole numbers Integers - whole numbers and the negative numbers (-3, -2, -1, 0, 1, 2, 3) Real numbers - numbers that can be represented by fractions or decimal values (1/3, 2.357, 35.666) Real numbers and ERROR

CSCI N241 Web Design: The Essentials of Computing
13. ASCII
ASCII - American Standard Code for Information Exchange Text character converts to Decimal which converts to Binary ASCII Character Decimal Value Binary Value A 65 1000001 a 97 1100001

CSCI N241 Web Design: The Essentials of Computing
14. The Translation Trap
Computers track different kinds of information in different ways.

CSCI N241 Web Design: The Essentials of Computing
15. Manipulation
Memory just holds information 1. To Store and Retrieve 2. Cannot really change anything directly in memory. Registers are the "information garages". 1. Places to hold values while they are being manipulated.

CSCI N241 Web Design: The Essentials of Computing
16. Simple Tasks
A number of simple commands can be combined in very complex ways ¨Store in 1's and 0's Set of basic commands are built into a computer chip. Each command is represented by a number. Basic, machine-specific commands are sometimes referred to as machine language.

CSCI N241 Web Design: The Essentials of Computing
17. Some Elemental Commands
LOAD - Copies value from memory to register STORE - Copies value from register to memory ADD - Adds up values of two registers subtraction, multiplication and division are a derivative of addition TEST - Compares two values JUMP - Go to another command in the list of instructions HALT - The list of commands is finished (if there is no HALT, you have a runaway computer)

CSCI N241 Web Design: The Essentials of Computing
18. FETCH/EXECUTE Cycle
PROGRAM (or software) ¨a list of instructions to a computer for information ¨stored in 1's and 0's The CYCLE ¨Fetch a command ¨Execute the command ¨Fetch another command ¨Repeat until told to HALT

CSCI N241 Web Design: The Essentials of Computing
19. NEARLY UNIVERSAL
Different programs change the way computers behave. This flexibility is why they are considered universal. Computers DO have limits - they are NEARLY universal Limited to 1's and 0's, BUT this is being overcome by speed and size of computing technology.

CSCI N241 Web Design: The Essentials of Computing
20. Introducing ABNIAC
The ABNIAC Page

CSCI N241 Web Design: The Essentials of Computing
21. What is ABNIAC
ABNIAC is the Absolute Beginners Numeric Integrator and Calculator

CSCI N241 Web Design: The Essentials of Computing
22. What does ABNIAC do?
What is will show us -A puzzle environment to practice problem solving -How computers store information -How simple opCodes are combined -A set of basic opCodes -What can go wrong in a computer program -Storage of instructions and data in memory

CSCI N241 Web Design: The Essentials of Computing
23. The opCodes in ABNIAC
Store Add Compare Jump Output ASCII output Halt

CSCI N241 Web Design: The Essentials of Computing
24. STORE
Represented by 1 Takes the value to store Takes the address to store it in Stores the value in the address

CSCI N241 Web Design: The Essentials of Computing
25. ADD
Represented by 2 Takes three addresses Adds values in first two addresses together Places the results in the third address For counters, places the result in one of the original cells

CSCI N241 Web Design: The Essentials of Computing
26. COMPARE
Represented by 3 Takes three addresses Looks at values in the first two addresses If they are equal, jumps to address in the third address Usually followed by a JUMP command Used to cause branches and loops

CSCI N241 Web Design: The Essentials of Computing
27. JUMP
Represented by 4 Takes one address Jumps to the instruction in the address Used for loops and branches

CSCI N241 Web Design: The Essentials of Computing
28. OUTPUT
Represented by 5 Takes one address Prints out the value in the address to the output area

CSCI N241 Web Design: The Essentials of Computing
29. ASCII OUTPUT
Represented by 6 Takes one address Prints out the value in the address to the output area Translates contents to ASCII first Use ASCII chart in online help for hints

CSCI N241 Web Design: The Essentials of Computing
30. HALT
Represented by 7 Takes no arguments Used to stop program execution If it is not encountered, unpredictable results will occur

• Binary Tutorial

The Binary System

• Binary Numbering System

  Decimal	Binary	2^3 (8s)	2^2 (4s)	2^1 (2s)	2^0 (1s)
  0	0	0	0	0	0
  1	1	0	0	0	1
  2	10	0	0	1	0
  3	11	0	0	1	1
  ...	...	...	...	...	...
  8	1000	1	0	0	0

Converting Binary to Decimal

• Converting Binary to Decimal

  Convert 1001 to Decimal Place Value 8 4 2 1 Binary Value 1 0 0 1 Decimal Value 8 0 0 1 Answer = 9 CAN YOU CONVERT 1101 TO A DECIMAL VALUE?

Converting Decimal to Binary

• Converting Decimal to Binary

  Convert 13 to Binary Place Value 16 8 4 2 1 Binary Value - 1 1 0 1 Decimal Value - - - - - HOW DO YOU CHECK YOUR ANSWER?

Binary and Other Kinds of Information

• Whole numbers
• Integers - whole numbers and the negative numbers (-3, -2, -1, 0, 1, 2, 3)
• Real numbers - numbers that can be represented by fractions or decimal values (1/3, 2.357, 35.666)
• Real numbers and ERROR

ASCII

• ASCII - American Standard Code for Information Exchange
• Text character converts to Decimal which converts to Binary
  

  ASCII
  Character	Decimal Value	Binary Value
  A	65	1000001
  a	97	1100001

The Translation Trap

• Computers track different kinds of information in different ways.

Manipulation

• Memory just holds information
  1. To Store and Retrieve
  2. Cannot really change anything directly in memory.
• Registers are the "information garages".
  1. Places to hold values while they are being manipulated.

Simple Tasks

• A number of simple commands can be combined in very complex ways
  ¨Store in 1's and 0's
• Set of basic commands are built into a computer chip.
• Each command is represented by a number.
• Basic, machine-specific commands are sometimes referred to as machine language.

Some Elemental Commands

• LOAD - Copies value from memory to register
• STORE - Copies value from register to memory
• ADD - Adds up values of two registers
  subtraction, multiplication and division are a derivative of addition
• TEST - Compares two values
• JUMP - Go to another command in the list of instructions
• HALT - The list of commands is finished (if there is no HALT, you have a runaway computer)

FETCH/EXECUTE Cycle

• PROGRAM (or software)
  ¨a list of instructions to a computer for information
  ¨stored in 1's and 0's
• The CYCLE
  ¨Fetch a command
  ¨Execute the command
  ¨Fetch another command
  ¨Repeat until told to HALT

NEARLY UNIVERSAL

• Different programs change the way computers behave.
• This flexibility is why they are considered universal.
• Computers DO have limits - they are NEARLY universal
• Limited to 1's and 0's, BUT this is being overcome by speed and size of computing technology.

Introducing ABNIAC

• The ABNIAC Page

What is ABNIAC

• ABNIAC is the
  Absolute
  Beginners
  Numeric
  Integrator and
  Calculator

What does ABNIAC do?

• What is will show us
  -A puzzle environment to practice problem solving
  -How computers store information
  -How simple opCodes are combined
  -A set of basic opCodes
  -What can go wrong in a computer program
  -Storage of instructions and data in memory

The opCodes in ABNIAC

• Store Add Compare
• Jump Output ASCII output
• Halt

STORE

• Represented by 1
• Takes the value to store
• Takes the address to store it in
• Stores the value in the address

ADD

• Represented by 2
• Takes three addresses
• Adds values in first two addresses together
• Places the results in the third address
• For counters, places the result in one of the original cells

COMPARE

• Represented by 3
• Takes three addresses
• Looks at values in the first two addresses
• If they are equal, jumps to address in the third address
• Usually followed by a JUMP command
• Used to cause branches and loops

JUMP

• Represented by 4
• Takes one address
• Jumps to the instruction in the address
• Used for loops and branches

OUTPUT

• Represented by 5
• Takes one address
• Prints out the value in the address to the output area

ASCII OUTPUT

• Represented by 6
• Takes one address
• Prints out the value in the address to the output area
• Translates contents to ASCII first
• Use ASCII chart in online help for hints

HALT

• Represented by 7
• Takes no arguments
• Used to stop program execution
• If it is not encountered, unpredictable results will occur