CSCI111: Introduction

CSCI 111
Chapter 1: Introduction (1.1 - 1.3)

Java Class Library
(All docs)

Overview

Computer processing

slide 1-4

Computers
(how smart are they?)

     - Where are they? (my work.....)

Two primary elements : slide 5

  1. hardware slide 6-7
  2. software (programs)

  3. firmware (hardwired)

Peripherals Input Devices ? Computer ? Output Devices? (stdin, stdout) slide 8

Kinds of machines

digital computers

analog computer - abacus, slide rule, thermometer, watch ...careful... slide 10

Languages They are called digital because that is the language they understand.

Computers only work with off and on - 0's and 1's ... how?
Thus instructions must be in the form of these 0's and 1's. Each individual 1 or 0 is called a bit (binary digit)
real programmers slides 11-15

Hardware Components

Computer Specs slide 17

More on Memory slide 18 - 22

Computers work with logic. The CPU actually has two components:

  1. The ALU (Arithmetic Logic Unit) only really work with logic and arithemetic functions such as add, subtract

  2. The Control Unit directs the operations: with hardware manipulation such as placing a value in a particular location or reading a value from a location.
slides 25-27

It does these operations very fast - MIPs (million instructions per second). The fastest now is trillions of operations per second.

Monitors slide 28,
Modems slide 29, (most familiar is voiceband modem, but these days: cable modems , DSL modems , optical modems for transmitting over optical fibers)

The software the computer uses needs to be in the instruction set the machine can understand. As mentioned earlier, this is comprised soley of 0's and 1's. It is called Machine Language or Machine Code.

Humans do not work well with machine language. A series of 0's and 1's can be difficult for humans. But that was all the original computers had to use.

Languages for machines have evolved into ones which are easier to program slides 55,56

High-level languages are easier for humans, but Source Code must be translated into machine code so the machine can understand. Such programs are called translators Two types are

  1. Interpreters: programs which translate and execute a high-level language into machine code one line at a time ... thus errors also show up one line at a time (the line with the problem)
  2. Compilers: programs which translate a high-level language into machine code all at once. They usually provide the compiled code and error messages. None of the program (compiled code) can be run until there are no errors. In lab 2 we will see how the compiler can help us find our errors.
slides 57,58

In order to be cross-platform Java combines these techniques and uses The Java Virtual Machine (JVM) and Java bytecode

Networks and The Internet

The Internet a world-wide collection of computers connected via a network of communication channels.

A collection of sites and suddenly we have the WWW the World-Wide Web.

Addresses look like

Two important sites :-)

slide 30 - 42

Graphical User Interfaces (GUIs)

Compare to

Executable Documents

One reason Java caught on so well is because it allows a web page to have more than just information. Java allows executables as well. Basically this just means a program that can run on the web page. The browser that the page is being viewed from must be java-enabled

A copy of the text author's slides used in the lecture.