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PTTE 428 Fall 2005 Loosely covering chapters 3 & 4 of the text. 1 ITED 328 Spring 2004 Announcements: Lab to do installation of Windows NT will take place in Room 101 in the basement level of the CHE Building. We are covering Chapters 3 & 4 tonight Class Website (it should be working): http://www.if.uidaho.edu/~nimsrj/ 2 ITED 328 Spring 2004 Back tracking a bit to chapter 2: For computers, always start counting at zero Binary numbers base 2, only 2 values 0 or 1 Decimal numbers are base 10 Octal numbers are base 8. 0-8 (HEX) Hexadecimal numbers are base 16, 0-9, A, B,C,D,E,F 3 ITED 328 Powers of 2 2 2 2 2 2 2 2 2 2 2 ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ 0 1 2 3 4 6 7 8 9 5 Spring 2004 = = = = = = = = = = 1 2 4 8 16 64 128 512 1024 32 Bit positions in a binary number correspond to the powers of 2. 4 ITED 328 Spring 2004 Example Problem: 1) 100 in base 10 = ? in binary 100 - 64 = 36 36 - 32 = 4 5 ITED 328 Spring 2004 Example Problem: 2) 10101 in base 2 ( binary) = ? in decimal Bit position : 16 8 4 2 1 What is really there: 16 + 0 + 4 + 0 + 1 = ? 6 ITED 328 1 2 3 4 5 6 7 8 Spring 2004 MAIN FUNCTIONS of an OPERATING SYSTEM: Program execution I/O operation File System manipulation Communications Error Detection Resource allocation Accounting Protection 7 ITED 328 Spring 2004 SYSTEM CALLS Process control File management Device management Information maintenance Communications 8 ITED 328 Spring 2004 Fact to remember: When a program is running, it is called a “Process”. 9 ITED 328 Spring 2004 SYSTEM Programs| File management Status information File modification Programming language support Program loading and execution 10 ITED 328 Spring 2004 Most computers these days use a layered approach to system design. 11 ITED 328 Spring 2004 Chapter 3 Computer Software Software can be divided into several levels 12 ITED 328 Spring 2004 The operating system and its associated system level programs needed to run the computer ( utilities, printer drivers, boot files, BIOS, I/O port interface software, user interface software). Application programs to perform specific user needs ( word processors, spread sheet programs, tax programs, email programs, simulation programs, games, custom developed programs). 13 ITED 328 Spring 2004 Software is made up of files but not all files are software there are programs and data files. 14 ITED 328 Spring 2004 The User interface is the communication link to the applications of the computer. The application programs relay information and requests to the operating system , which in turn will interact with the hardware. 15 ITED 328 Spring 2004 Types of operating Systems: Stand alone or single user system -One set of I/O and only one user at a time. Multi-user Operating System -- A system that can have more than one set of users and I/O at the same time. A main frame. 16 ITED 328 Spring 2004 Network Operating System (NOS) A system that shares resources ( i.e. printers) or information and provides communications. ( The school network of computers or at work). 17 ITED 328 Spring 2004 Multitasking Operating System - A system that can run multiple programs at the same time. 18 ITED 328 Spring 2004 Embedded Operating Systems – a self contained operating system that is dedicated to a specific function. ( Robotics, Air planes, Automobiles.) 19 ITED 328 Spring 2004 multi threaded: Sharing a single CPU between multiple tasks (or "threads") in a way designed to minimize the time required to switch threads. This is accomplished by sharing as much as possible of the program execution environment between the different threads so that very little state needs to be saved and restored when changing thread. 20 ITED 328 Spring 2004 Multithreading differs from multitasking in that threads share more of their environment with each other than do tasks under multitasking. Threads may be distinguished only by the value of their program counters and stack pointers while sharing a single address space and set of global variables. There is thus very little protection of one thread from another, in contrast to multitasking. 21 ITED 328 Spring 2004 Desktop Operating System - The personal PC. A windows or MAC. 22 ITED 328 Spring 2004 Common operating systems: Various flavors of windows: windows 3.1, windows 95, windows 98, windows 2000, windows XP (home and Professional versions) Windows ME , Windows CE A Windows NT or Windows 2000 computer can be configured as a server. (You need extra software to do this,, which you have to buy separately) 23 ITED 328 Spring 2004 Linux flavors: REDHAT, SUSE, Mandrake,embedded Linux (Linux is a PC version of Unix) (If you learn Linux, you have learned most of UNIX as well) Linux can be configured to be a server type computer( the software for this comes as part of the package). 24 ITED 328 Spring 2004 Others: Macintosh Be Lindows 25 ITED 328 Spring 2004 System Level Software, the average everyday use does not see. Memory management software allocates / deallocates sections of memory used by various programs. 26 ITED 328 Spring 2004 APPLICATION SOFTWARE The everyday user can access if they have permission. Types of application software: Document production :Word processors, Web publishing. Spread Sheet software: Excel, Lotus 123 27 ITED 328 Spring 2004 28 ITED 328 Spring 2004 Database software: access, Oracle, DBMS - Data Base Management System or Software Several kinds of DBs : Relational, Hiearchial ( old) , Object Oriented( Pass Port uses this). Only specific data types are allowed. All use some form of SQL ( Structured Query Language) 29 ITED 328 Spring 2004 Presentation software: Power point Accounting software Games, Graphics software CAD systems, CASE systems 30 ITED 328 Spring 2004 Most software that is purchased requires some sort of license agreement in order to operate, Some require keys, either software or hardware, There is also "shareware" and "freeware" Open Source. "Share ware" is TBD "Free ware" is TBD 31 ITED 328 Spring 2004 Freeware is software written by enthusiasts and distributed at no charge by users' groups, or via the World-Wide Web, electronic mail, bulletin boards, Usenet, or other electronic media. 32 ITED 328 Spring 2004 Shareware is software obtained (downloaded) and redistributed for free, but most often is under copyright and does legally require a payment in the EULA, at least beyond the evaluation period or for commercial applications. This payment, as well as fulfilling the user's legal obligations, may buy additional support, documentation, or functionality. 33 ITED 328 Spring 2004 Several ways to install software: self installing executables, zip files, the good old fashioned way - manually , (also via disk imaging from a server) NOTE: I highly recommend rebooting after ANY windows application installation 34 ITED 328 Spring 2004 REGSITRY: is a database of the configuration settings used on a windows operating system computer. It replaces a lot of the *.ini files that used to hold the same information. 35 ITED 328 Spring 2004 Uninstalling may or may not be a clean process. Joke: How may software engineers does it take to change a light bulb? 36 ITED 328 Spring 2004 TAKE A BREAK ! 37 ITED 328 Spring 2004 Chapter 4 FILES file naming conventions - a good way to do it Most file systems follow some sort of convention A file designation : filename. extension Depends on limits imposed by the OS. 38 ITED 328 Spring 2004 A limit to length and type of characters used in the filename. Depends on limits imposed by the OS. 39 ITED 328 Spring 2004 The extensions have special meanings: .doc for document, .exe for executible, .f for fortran source file, .c for C source file, .bas for a basic file, .xls for a spreadsheet file,etc. A path is the complele file designation for a file. One cannot use a reserved word for a file name. 40 ITED 328 Spring 2004 File management system - how files are arranged and kept track of, in some sort of hierarch or tree structure. 41 ITED 328 Spring 2004 DO THIS NOW: Pull up a top level widow, expand a directory, do a screen dump, print it out, put your name on it and hand it in! 42 ITED 328 Spring 2004 Basic file operations:create, rename, move, copy, delete. (if programming can open and close them too) 43 ITED 328 Spring 2004 Security Issues Viruses - self replication code that attaches itself to a file, and spreads via transfer of the infected file, somewhat passive Worms - A program that spawns copies of itself in your system, eventually using up the system resources. Especially dangerous over a network. 44 ITED 328 Spring 2004 Trojans - a file that contains legitimate code and additional code that will use your computer resources without your knowledge (email, act as a router, be used as a storage area). Denial of service attack (DOS) - fills up your hard drive so the computer eventually halts. 45 ITED 328 Spring 2004 Good idea to have a personal firewall and use virus checking software. WHY ? If your computer is involved in some illegal activity, you are responsible, even if you are unaware of the involvement! 46 ITED 328 Spring 2004 2 kinds of virus checking software one that scans for specific patterns and one that looks for heuristics ( recognizes informal rules or patterns) 47 ITED 328 Spring 2004 Always good to backup your computer! Why ? What could fail? 48 ITED 328 Spring 2004 Why? Sooner or later you WILL have a failure. What could fail? Hardware failure like a drive or a component on the motherboard. Software failure in the operating system, or in one of the application programs. Or you get invaded by a worm / virus or other attack. 49 ITED 328 Spring 2004 How to do ? Over the network if at work. Use one or more forms of media to transfer files. Have media disks to reinstall applications, os. suggest keeping a log to track what was installed, the date, important data. 50 ITED 328 Spring 2004 Types of backups: Fullbackup – everything. Differential backup - only the files that changed. partial or incremental backup - only files that were added or changed since last backup. 51