Friday, October 1, 2010

Chapter 4: Software Basics: The Ghost in the Machine

-open source: open for the public
-what makes it reliable: updates
-who creates the open source ideas:
2 kinds of software and systems
    1. reliable on open source idea
    2. doesn't have open source idea
  • Lins Torvalds: created the linux,
  • linux is the operating system is the best known ex. of open source software
  • film and animation workstations, scientific comps, and some handhelds
3 major categories:
  1. Translator programs such as compilers: enable programs to create other software
  2. software applications: help comp users solve probs
  3. system software: coordinate hardware operations and does behind the scences work the comp use hardly sees
-Examples of compilers: C and C++ intel etc
-Examples of application compilers: photoshop, word, paint, etc.

OS vs Application Software

-Food of Thought: the hardware in a comp system is equipped to produce whatever output a user requests
A Fast, Stupid Machine
  • prgrammers start with an algorithm (step by step instructions in a natural language ...english)
  • the steps are error prone
  • the steps are translated into vocab of programming language: this has too many steps, complicated, EXACT instructions
TOOLS FOR USERS
-Many Software companies have replaced their printed documentation with:
  1. Tutorials
  2. Reference materials
  3. Help files
  4. on-line help
-Upgrading: Users can upgrade a program to the new version by paying an upgrade fee to the software manufacturer
-Newer releases often have additional features and fewer bugs
Bugs are things that make the computer slower or an error

COMPATIBILITY
-It allows software to function properly with the hardware, operating system, and peripherals
-Programs written for one type of computer system may not work on another
- a hardware needs a compatibile software

DISCLAIMERS
-Software manufacturers limit their liability for software by selling the software "as is."
-manufacturers don't sell their website to a person for their needs

LICENSING: Commercial software is copyrighted so it can't be legally duplicated for distribution to others
  • software license
  • volume license
DISTRIBUTION: Software is distributed via:
  • direct sale
  • retail stores
  • Mail-order catalogs
  • web-sites
  • not all software is copyrighted: ( public domain software, Shareware)
-you need a license to work on a software
-can't use one software on all others, like some "cracked" softwares

WEB APPLICATIONS
-fall into several categories
  • Some simple Web applications perform simple data-processing tasks that could also be performed by traditional programs running on stand alone PCs
  • Most web applications take advantage of the Wed's connectivity
  • Many Web applications leverage the Web's strength as a huge repository of info.
  • Some Web applications support online business transactions (CNN)
  • News-oriented Web applications provide up-to-the-min. repotrts on a myriad of subjects
  • Other Web applications support a more traditional form of info. broascasting
-the keyboard is called a web application
-most web applications take advantage of the web connectivity to be published
             - web applications: will stay in your comp and not go onto the internet unless its saved on "e"
             -  add index pg to domain range
-IP address: 1921 or xxx.xxx.xxx.xxx
-you can call it yourname.com (the domain name)

SOFTWARE BUNDLES
-vertical-market and custom software
-Tends to cost far more than mass- market apps
-job specific software
  • medical billings
  • library cataloguing
  • legal references software
  • restaurant management
  • single-chent software needs
SYSTEM SOFTWARE
-A class of software that includes the operating system and utility programs, handlies these details, and hundreds of other tasks behind the scences.
- operating system

OPERATING SYSTEM FUNCTIONS:
  • supports multitasking
  • manages virtual memory
  • maintains file system
  • responsible for authentication and authorization
HW: What is the diff b/t authentications and authorization? Responsibilities? Examples.
What does the operating system do?
What is the diff b/t utillity programs and device drivers?
UTILITY PROGRAMS
-Serve as tools for doing system maintenance and repairs that aren't automatically handled by the operating system.

MAKE IT EASIER FOR USERS TO:
  • copy files b/t storage devices
  • repair damaged data files
  • translate files so that diff. programs can read them
  • guard against viruses and potentially harmful prog. (ch. on comp. securities and risks)
  • compres files so they tak up less disk space
  • perform other imp. if unexciting tasks
HARDWARE-SOFTWARE CONNECTIONS
- Symantec Norton Utilities is a popular utility package that includes software tools for recovering damaged files, repairing damaged disks, and improving disk performance.
        -viruses, trogens, maulware-softwares that are attacking our comps.

DEVICE DRIVERS
-Small programs kthat enable I/0 devices - keyboard, mouse, printer, and others- to comm w./ the comp
- included w/ the operating system or bundled ww/ peripherals

WHERE THE OPERATING SYSTEM LIVES
-Some comps. store their operating system in ROM
-others include only prt of it in ROM
  • The remainder of the operating systems is loaded into memory in a process called booting which occurs when you turn on the comp.
-Most of the time the operating works behind the scences
-interacting with the operating system is like interacting with an app can be intuitve or challenging and it depends on something called user interface.

USER INTERFACE
-the interface defines the look and feel of the comp. experience from a human point of view
-desktop operating system
     -MS - DOS is a disk opeating system in which the user interacts using characters
  • letters
  • numbers
  • symbols
HUMAN-MACHINE CONNECTION
-features include
  • command-line interface (commands are typed)
  • menu-driven interface (commands are chosen from on-screen lists)
-command line interface is called that because you are commanding to have certain info.

GRAPHICAL USER INTERFACE
-Mac OS developed by Macintosh in 1984 using GUI.
-Microsoft Windows is now the most popular operating system

MULTIPLE USER OPERATING SYSTEM:UNIX AND LINUX
-UNIX: developed by Bell Labs before personal coms were availabe'
-LINUX: created by Linus Torvalds and cont. to be a work in progress
-UNIX allows a timesharing comp to comm with several other comps or terminals at once

-linux is free for anyone to use or improve
-UNIX remains the dominant operating system for internet servers
-some form of UNIX is available for personal comps, workstations, servers, mainframes, and supercomps.
-EX: of UNIX are solarists

Hardware                                                                    Software
 - window vista
-winsows Server 2003
-windows XP
-windows ME
microsoft Windows CE

-cross platforms app such as micro office and ADOBE PHOTOSHOP
are programs that are available in similar versions for multiple platforms
-mac users can buy software emulation programs that:
  • create a stimulated windows machine in the Mac
  • translate
Future users interfaces will be bulit around emerging development technologies such as:
  • applications (end)
  • natural language interfaces
  • agents
  • virtual realities
FILE MANAGEMENT:
- Files can be scattered all over the system which often makes data manadement difficult
       solution: organize data files logically
-Both windows and Mac support the notion of common system folders with self-explanatory names:
  • My docs (dos)
  • my pics (pics)
  • my music (music)
FILE MANAGEMENT UTILITIES:
  • view rename copy move and delete files & folders
  • Hierachies (arrangmeant of items) help w/ organization
  • help w/ locating a file
  • get size, file type, & last modification date
EX of Hierachy: is a folder with subfolders in it
-if u have a lot of the same folder that has the same name and u did one today with new modifications u go to details (under my docs and view) and u look at the dates.

MANAGEMENT FILES FROM APPLICATIONS:
  • Operations: Open, Save As, Save, and Close
DEFRAGMENTATION: (pg 126)
- eliminates fragmented files by changing the assignment of clusters and files.
- can significantly improve the performanceof a disk drive
-recommended to do once a month
- ppl do this to eliminate empty spaces

SOFTWARE PIRACY:
- illegal duplication of copyrighted software
  • the software industry is $50 billion industry
  • 1/3 of softeware is illegally copied

No comments:

Post a Comment