7/18/16 Objectives Chapter 1: Introduction to ✦ To understand computer basics, programs, and operating systems (§§1.2–1.4). Computers, Programs, and Java ✦ To describe the relationship between Java and the World Wide Web (§1.5). ✦ To understand the meaning of Java language specification, API, JDK, and IDE (§1.6). ✦ To write a simple Java program (§1.7). CS1: Java Programming ✦ To display output on the console (§1.7). Colorado State University ✦ To explain the basic syntax of a Java program (§1.7). ✦ To create, compile, and run Java programs (§1.8). ✦ To use sound Java programming style and document programs properly (§1.9). ✦ To explain the differences between syntax errors, runtime errors, and logic Original slides by Daniel Liang errors (§1.10). Modified slides by Chris Wilcox ✦ To develop Java programs using NetBeans (§1.11). ✦ To develop Java programs using Eclipse (§1.12). Liang, Introduction to Java Programming, Tenth Edition, (c) 2015 Pearson Education, Inc. All Liang, Introduction to Java Programming, Tenth Edition, (c) 2015 Pearson Education, Inc. All 1 2 rights reserved. rights reserved. CPU What is a Computer? The central processing unit (CPU) is the brain of a computer. It A computer consists of a CPU, memory, hard disk, floppy disk, retrieves instructions from memory and executes them. The CPU speed is measured in gigahertz (GHz), with 1 gigahertz equaling 1 monitor, printer, and communication devices. billion cycles per second. The speed of the CPU has been improved continuously. If you buy a PC now, you might get an Intel Core i7 running at 2.8 to 4.0 gigahertz. Bus Bus Communication Input Output Storage Memory CPU Devices Devices Devices Devices Output Storage Communication Input Memory CPU Devices Devices Devices Devices e.g., Monitor, e.g., Disk, CD, e.g., Modem, e.g., Keyboard, Printer e.g., Disk, CD, e.g., Keyboard, e.g., Monitor, and Tape and NIC Mouse e.g., Modem, and Tape and NIC Mouse Printer Liang, Introduction to Java Programming, Tenth Edition, (c) 2015 Pearson Education, Inc. All Liang, Introduction to Java Programming, Tenth Edition, (c) 2015 Pearson Education, Inc. All 3 4 rights reserved. rights reserved. 1
7/18/16 Memory How Data is Stored? Data of various kinds, such as numbers, Memory is to store data and program instructions for CPU to characters, and strings, are encoded as a execute. A memory unit is an ordered sequence of bytes, each holds series of bits (zeros and ones). Computers eight bits. A program and its data must be placed in memory before use zeros and ones because digital devices Memory address Memory content have two stable states, which are referred to they can be executed. A memory byte is never empty, but it can be as zero and one by convention. The . . uninitialized. The current content of a memory byte is overwrittent programmers need not to be concerned about . . whenever new information is placed in it. If you buy a PC today, it the encoding and decoding of data, which is . . 2000 01001010 Encoding for character ‘J’ performed automatically by the system based might have 8 gigabytes (Gb) of memory. 2001 01100001 Encoding for character ‘a’ on the encoding scheme. The encoding Bus 2002 01110110 Encoding for character ‘v’ scheme varies. For example, character ‘J’ is 2003 01100001 Encoding for character ‘a’ represented by 01001010 in one byte. A 2004 00000011 Encoding for number 3 small number such as three can be stored in a Output Storage Communication Input single byte. If computer needs to store a Memory CPU Devices Devices Devices Devices large number that cannot fit into a single e.g., Disk, CD, e.g., Keyboard, e.g., Monitor, e.g., Modem, byte, it uses a number of adjacent bytes. No and Tape and NIC Mouse Printer two data can share or split a same byte. A byte is the minimum storage unit. Liang, Introduction to Java Programming, Tenth Edition, (c) 2015 Pearson Education, Inc. All Liang, Introduction to Java Programming, Tenth Edition, (c) 2015 Pearson Education, Inc. All 5 6 rights reserved. rights reserved. Output Devices: Monitor Storage Devices Memory is volatile, because information is lost when the power is The monitor displays information (text and graphics). The resolution off. Programs and data are permanently stored on storage devices and dot pitch determine the quality of the display. Laptops today and are moved to memory when the computer actually uses them. often approach or exceed the quality of an high-definition (HD) There are three main types of storage devices: disk drives (hard television, which is 1920x1080 pixels, and mobile devices are often disks and floppy disks), optical drives (CD, DVD), and tape drives. even better. For example the Samsung Galaxy S7 has a screen with If you buy a PC today, it might have a 500 gigabyte (Gb) or 1 2560x1440 pixel resolution. terabyte (Tb) hard drive, or solid state storage. Bus Bus Communication Input Output Storage Memory CPU Devices Devices Devices Devices Output Storage Communication Input Memory CPU Devices Devices Devices Devices e.g., Disk, CD, e.g., Modem, e.g., Keyboard, e.g., Monitor, Printer and Tape and NIC Mouse e.g., Disk, CD, e.g., Keyboard, e.g., Monitor, e.g., Modem, and Tape and NIC Mouse Printer Liang, Introduction to Java Programming, Tenth Edition, (c) 2015 Pearson Education, Inc. All Liang, Introduction to Java Programming, Tenth Edition, (c) 2015 Pearson Education, Inc. All 7 8 rights reserved. rights reserved. 2
7/18/16 Communication Devices Monitor Resolution and Dot Pitch A regular modem uses a phone line and can transfer data in a speed up to resolution The screen resolution specifies the number of pixels in 56,000 bps (bits per second). A DSL (digital subscriber line) also uses a horizontal and vertical dimensions of the display device. phone line and can transfer data in a speed 20 times faster than a regular Pixels (short for “picture elements”) are tiny dots that form modem. A cable modem uses the TV cable line maintained by the cable an image on the screen. A common resolution for a 17-inch company. A cable modem is as fast as a DSL. Network interface card screen, for example, is 1,024 pixels wide and 768 pixels ( NIC ) is a device to connect a computer to a local area network (LAN). high. The resolution can be set manually. The higher the The LAN is commonly used in business, universities, and government resolution, the sharper and clearer the image is. organizations. A typical type of NIC, called 10BaseT , can transfer data at 10 mbps (million bits per second). Bus dot pitch The dot pitch is the amount of space between pixels, Storage Communication Input Output measured in millimeters. The smaller the dot pitch, the Memory CPU Devices Devices Devices Devices sharper the display. e.g., Disk, CD, e.g., Modem, e.g., Keyboard, e.g., Monitor, and Tape Mouse Printer and NIC Liang, Introduction to Java Programming, Tenth Edition, (c) 2015 Pearson Education, Inc. All Liang, Introduction to Java Programming, Tenth Edition, (c) 2015 Pearson Education, Inc. All 9 10 rights reserved. rights reserved. Programming Languages Programs Machine Language Assembly Language High-Level Language Computer programs , known as software , are instructions to Machine language is a set of primitive instructions the computer. built into every computer. The instructions are in the form of binary code, so you have to enter binary You tell a computer what to do through programs. Without codes for various instructions. Program with native programs, a computer is an empty machine. Computers do machine language is a tedious process. Moreover not understand human languages, so you need to use the programs are highly difficult to read and computer languages to communicate with them. modify. For example, to add two numbers, you might write an instruction in binary like this: Programs are written using programming languages. 1101101010011010 Liang, Introduction to Java Programming, Tenth Edition, (c) 2015 Pearson Education, Inc. All Liang, Introduction to Java Programming, Tenth Edition, (c) 2015 Pearson Education, Inc. All 11 12 rights reserved. rights reserved. 3
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