Mrs. Ulshafer August, 2013 Java Programming Chapter 1

What is a Computer? An Electronic machine Accepts information Data Processes information based on instructions Provides results or new information

Program List of instructions written in a special language Lets computers solve problems Specific order to be performed Tells computer what to do What is a Computer?

Journal 1: Prompt: What do you expect to get out of this course? What are you most looking forward to this semester?

Uses of 1 st Computers Calculators Vs Computers Computers make DECISIONS Navigation Census Bureau Military

Hardware: (Physical Components) Base Unit CPU Storage Devices CD-ROM, USB, ZIP Hard Disk Contained within base unit The Modern Computer

Hardware: (Physical Components) Keyboard, mouse and disk drives Input of data Monitor View input or output Software – Programs that tell computer what to do The Modern Computer

4 Subsystems of a Computer Input Devices tools that accept data Memory Electronic storage of instructions and data

4 Subsystems of a Computer Central Processing Unit (CPU) Processes data Controls flow of data Output Devices Tools where data can be displayed Monitors printers

Directions of Data Flow Input Output CPU Memory

Read-Only Memory (ROM) Basic Operating Instructions Permanent part CAN NOT BE CHANGED Random Access Memory (RAM) Main memory Stored temporarily Lost after shut down

Memory Auxiliary Memory Storage long term storage Reusable Thumb Drives CD – ROM Hard Drive

Memory Workings of Memory access in Auxiliary copy into RAM copy into registers Actions taken copied back into RAM copied back in auxiliary

CPU Directs all activities Information flows through “BRAIN” only follows instructions Can NOT think Add or compare numbers only Changes operations into addition Solves problems in nanoseconds

Number Systems Base 2 Binary Uses only 2 digits 0 for off, 1 for on states of electrical circuits powers of 2

Explain what the following means: “There are only 10 types of people in the world: Those who understand binary and those that don’t”

Storing Data Binary system stores data Each 0 or 1 is a bit (BI-nary digi-T) Bytes: RAM Measured in bytes MB- GB- TB– 8 Bit Unit 2 20 = 1, 000, = 1, 000, 000, = 1,000, 000, 000, 000

Storing Data ASCII Code American Standard Code for Information Interchange Letters, numbers and characters are turned into numbers which are turned into binary code Always 1 byte long (8 bits)

Operating Systems Windows 7- GUI Special program Graphical user interface (GUI) Pictures (icons) to create a user- friendly environment Provides applications and tools Object base operating system Each item that appears is an object

Programming Languages Machine Language Lowest Level Directly typing in 0s and 1s Depends on CPU type High – Level Languages FORTRAN, COBOL, PASCAL, C, C++ Chunks of normal language Compiler translates into machine

Java Started for applets- downloadable programs Object-Oriented Language Data described by objects Then told what to do organized Must have a class Must have methods – instructions

Java Editor – place to enter/modify Java text Source Code Java written text Compiler - Translates into Java bytecode - Enforces rules of language - Checks for errors in syntax and some logic

Java Debug- Process of removing errors from the program Virtual Machine Reads and runs bytecode Portable - can run programs on any platform (mac, linux, windows) Safe