CS 112 Introduction to Programming

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CS 112 Introduction to Programming

• Lecture 3
• Computer Hardware/Software, and Sun SDK
• Richard Yang

2
Outline

• Admin. and review
• Computer hardware/software
• Write your first Java program

3
Admin.

• Please finish reading Chap. 1.0-1.4
• Assignment 1 is online due Sep. 18
• Must run on Sun SDK
• Can be either Unix or Windows
• Teaching fellows will hold office hours
  M,Tue,Thur, from 300-500pm at Dunham Garage
  computer lab (Dunham 120) to help you get started
• Only 18 computers, please schedule your time
• TFs can meet with you at other time as well,
  please send email to make an appointment

4
Review

• Different programming language levels
• Machine code, assembly code, high level languages
• A compiler translates a program in a high level
  language to machine code
• Java compiler compiles a Java program to the
  machine code of Java virtual machine thus Java
  needs an interpreter for execution
• Structure of a Java program
• A program consists of one or more classes
• A class consists of one or more methods
• A method consists of one or more statements
• Comments, identifiers, reserved words, and white
  space
• Our first Java program

5
Outline

• Admin. and review
• Computer hardware/software
• Write your first Java program

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Computer Environment Hardware

• Hardware
• the physical, tangible parts of a computer
• E.g., CPU, storage, keyboard, monitor

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Storing Information

• Computers store all information digitally
• E.g. numbers, text, audio, video, program
  instructions
• Information is stored in binary numbers
• A single binary digit (0 or 1) is called a bit
• A single bit can represent two possible states,
  like a light bulb that is either on (1) or off
  (0)
• Combinations of bits are used to store values

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Binary Bit Combinations
Each additional bit doubles the number of
possible combinations
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Information is Stored in Memory
Each memory cell has a numeric address, which
uniquely identifies it
9278 9279 9280 9281 9282 9283 9284 9285 9286
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The Central Processing Unit

• A CPU is also called a microprocessor

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The Central Processing Unit

• A CPU continuously follows the fetch-decode-execut
  e cycle

Retrieve an instruction from main memory
a b c d
fetch
load b, r1 load c, r2 add r1, r2, r3 load d,
r4 add r3, r4, r5 store r5, a
decode
execute
Determine what the instruction is
Carry out the instruction
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Computer Environment Software

• Operating System
• E.g., Windows 2000, Windows XP, Linux, Sun
  Solaris, Mac OS X
• manages resources such as CPU, memory, and disk
• controls all machine activities
• Application program
• generic term for any other kind of software
• compiler, interpreter, word processors, missile
  control systems, games

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Operating System

• What does an OS do?
• hides low level details of bare machine
• arbitrates competing resource demands
• Useful attributes
• multi-user
• multi-tasking

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Example Operating Systems

• Windows micro-kernel (make OS simple)
• Unix monolithic kernel (make OS more capable)
• Brief history
• successor to Multics (65-70)
• ambitious project at MIT
• pioneered most of the innovations in modern OS
• scaled down version by Thompson and Ritchie
  (1969)
• ATT (70-80s)
• Berkeley (BSD) produced a mature version (e.g.
  networking)
• various flavors of commercial Unix
• latest incarnation Linux
• main features
• processes
• files

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Unix File System

• Hierarchical name space (directories, files)
• same as folders and files on Windows
• Permanent storage
• Filename sequence of directory names ending with
  a file name (/usr/local/bin/foo)

/home/richter
Windows uses backslash C\cs112\lectures
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Unix Commands

• mkdir bar creates a directory bar)
• cd /usr/local/bin changes current dir. to
  /usr/local/bin
• pwd gives you the current
  directory
• ls lists files in current
  directory
• cp /usr/local/bin/foo /tmp/bar copies a
  file
• cp /usr/local/bin/foo bar copies to the
  current directory
• cat foo shows contents of file foo
  
• rm foo, or rmdir bar remove a
  file/directory
• chmod changes permissions
• man ls gets help on command ls

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Outline

• Admin. and review
• Computer hardware/software
• Write your first Java program
• Ultimately, you must test your program using Sun
  SDK
• Sun SDK options
• Pantheon Unix
• Windows

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Pantheon Environment

• The "Pantheon" is a collection of computers
  named after Greek gods
• Generally, you use ssh to login to eli.yale.edu
  eli.yale.edu will automatically direct you to
  one of the machineshttp//pantheon.yale.edu/help
  /ssh/
• They run the Unix operating system
• Linux
• Sun Solaris
• General help on pantheon is available at
• http//pantheon.yale.edu/help/

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Login, Edit, Compile, Run and Generate jar on a
Pantheon Machine

• - Help
• http//zoo.cs.yale.edu/classes/cs112/help/pantheon
  _java.html
• - Login to a pantheon machine using sshif you
  want to know the OS ? typeuname a
• Create a directory for your cs112 (only
  once)mkdir cs112
• Change to the directory
• cd cs112
• Edit your Java program using pico, or another
  editor, e.g., emacspico HelloJava.javatype in
  your program, press control-X, type y, press
  return

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Login, Edit, Compile, Run, and Generate .jar on a
Pantheon Machine (Cont.)

• Due to a mis-configuration, javac and java are
  not defined on some pantheon machines. Find
  themlocate javac
• Compile the Java program/usr/java/j2sdk1.4.0_01/
  bin/javac HelloJava.java
• Take a look to see that HelloJava.class is
  generatedls
• Run Java interpreter
• /usr/java/j2sdk1.4.0_01/bin/java HelloJava
• Since all homework assignments involve multiple
  files, you need to generate a jar file for
  submission. Suppose you also need to submit
  Errors.txt/usr/java/j2sdk1.4.0_01/bin/jar cvf
  RichardYang1.jar HelloJava.java Errors.txt
• Take a look to see that RichardYang1.java is
  generatedls

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Outline

• Admin. and review
• Computer hardware/software
• Write your first Java program
• Pantheon Unix
• Windows

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Edit, Compile, Run, and Generate .jar Using Sun
SDK without Forte

• - Help
• http//zoo.cs.yale.edu/classes/cs112/help/sunsdk.h
  tml
• Install Sun SDK, make sure you set the
  PATHvariablehttp//java.sun.com/j2se/1.4/install
  -windows.html
• Create a directory for your cs112 (only
  once)C\gtmkdir cs112
• Change to the directory
• C\gtcd cs112
• Edit your Java program using a text
  editorC\cs112gtnotepad HelloJava.java

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Edit, Compile, Run, and Generate .jar Using Sun
SDK without Forte (cont.)

• Compile the Java programC\cs112gtjavac
  HelloJava.java
• Take a look to see whether HelloJava.class is
  generatedC\cs112gtdir
• Run Java interpreter
• C\cs112gtjava HelloJava
• Since all homework assignments involve multiple
  files, you need to generate a jar file for
  submission. Suppose you also need to submit
  Errors.txt.C\cs112gtjar cvf RichardYang1.jar
  HelloJava.java Errors.txt
• Take a look to see that RichardYang1.java is
  generatedC\cs112gtdir

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Edit, Compile, Run, and Generate .jar Using Sun
SDK with Forte for Java

• Seehttp//zoo.cs.yale.edu/classes/cs112/help/fort
  e/index.html