Transcript Presentation

Java Programming
Chapter 1
Mrs. Ulshafer
August, 2013
What is a Computer?
 An Electronic machine
 Accepts information
 Data
 Processes information based
on instructions
 Provides results or new
information
What is a Computer?

Program
 List of instructions written in a
special language
 Lets computers solve problems
 Specific order to be performed
 Tells computer what to do
Journal 1:

Prompt:
 What do you expect to get
out of this course?

What are you most looking
forward to this semester?
Uses of
st
1
Computers
Navigation
Census Bureau
Military
Calculators Vs Computers
Computers make DECISIONS
The Modern Computer

Hardware: (Physical Components)
 Base Unit
 CPU
 Storage Devices
 CD-ROM, USB, ZIP
 Hard Disk
 Contained within base unit
The Modern Computer
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Hardware: (Physical Components)
 Keyboard, mouse and disk drives
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Input of data
Monitor
• View input or output
Software
– Programs that tell computer
what to do
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4 Subsystems of a Computer
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Input Devices
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tools that accept data
Memory
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Electronic storage of
instructions and data
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4 Subsystems of a Computer
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Central Processing Unit (CPU)
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Processes data
Controls flow of data
Output Devices
Tools where data can be
displayed
 Monitors printers

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Input
Directions of Data Flow
Memory
CPU
Output

Memory

Read-Only Memory (ROM)
Basic Operating Instructions
 Permanent part
 CAN NOT BE CHANGED
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Random Access Memory (RAM)
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Main memory
Stored temporarily
Lost after shut down

Memory
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Auxiliary Memory Storage
 long term storage
 Reusable
Thumb Drives
 CD – ROM
 Hard Drive
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Memory
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Workings of Memory

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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
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Add or compare numbers only
Changes operations into addition
Solves problems in nanoseconds
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Number Systems
 Base 2
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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

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(BI-nary digi-T)
Bytes: 8 Bit Unit
 RAM Measured in bytes
20 = 1, 000, 000
2
 MB230 = 1, 000, 000, 000
 GB40 = 1,000, 000, 000, 000
 TB– 2
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Storing Data
 ASCII Code
American Standard Code for
Information Interchange
 Letters, numbers and characters
are turned into numbers which
are turned into binary code
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Always 1 byte long (8 bits)
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Operating Systems
 Windows 7- GUI

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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

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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
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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
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