CHAPTER 14' COMPUTERSOFTWARE

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CHAPTER 14. COMPUTER SOFTWARE
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SOFTWARE

• Detailed instructions to control computer
  operation. There are two major types of software
• System software manages computer resources. Set
  of instructions that serves primarily as an
  intermediary between computer hardware and
  application programs. Manipulates computer
  hardware resources.
• Application software specific business
  application. A set of computer instructions that
  provide more specific functionality to a user.
  There are many different software applications in
  organizations today. Manipulate data or text to
  produce or provide information.

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Systems Software

• Class of programs that control and support the
  computer system and its information-processing
  activities.
• Systems software programs support application
  software by directing the basic functions of the
  computer.
• For example, when the computer is turned on, the
  initialization program (a systems program)
  prepares all devices for processing.

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Operating Systems

• Integrated system of programs that
• Manages the operations of the CPU
• Controls the input/output and storage resources
  and activities of the computer system
• Provides various support services as the computer
  executes application programs

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Operating Systems (continued)

• Performs four basic functions
• 1 User interface Provides a user interface
• Allows humans to communicate with the computer
• 2 Resource management
• Manages the hardware and networking resources of
  the system
• Virtual memory capability

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Operating Systems (continued)

• 3 File management
• Controls the creation, deletion, and access of
  files of data and programs
• Keeps track of the physical location of files
• 4Task management
• Manages the accomplishment of the computing tasks
  of end users
• Multitasking
• Multiprogramming
• Timesharing

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MULTIPROGRAMMING
The management of two or more tasks, programs,
running on the computer system at the same time.
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MULTITASKING
MULTIPROGRAMMING ON A SINGLE-USER SYSTEM SUCH AS
A MICROCOMPUTER
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TIME SHARING

• It is an extension of multiprogramming.
• In this mode, a number of users operate online
  with the same CPU, but each uses a different
  input/output terminal.
• The programs of these users are placed into
  partitions in primary storage.
• Execution of these programs rotates among all
  users, occurring so rapidly that it appears to
  each user as though he or she were the only using
  the computer.

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Operating Systems (continued)

• Popular Operating Systems
• Windows
• 95, 98, ME
• NT
• 2000
• XP
• UNIX
• Linux
• Mac OS X

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Types of Personal Application Software

• WORD PROCESSING
• SPREADSHEETS
• DATA MANAGEMENT
• GRAPHICS
• DESKTOP PUBLISHING
• GROUPWARE

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Types of Personal Application Software

• Spreadsheets Used for business analysis,
  planning, and modeling.
• Computer spreadsheet software transforms a
  computer screen into a ledger sheet, or grid, of
  coded rows and columns.
• They can be used for financial information, such
  as income statements or cash flow analysis.
• They are also used for forecasting sales,
  analyzing insurance programs, summarizing income
  tax data, and analyzing investments.
• They also offer data management and graphical
  capabilities. Ex Ms Excel, Lotus 1-2-3.

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Types of Personal Application Software

• Data management Data management software
  supports the storage, retrieval, and manipulation
  of related data.
• Produce forms, reports, other documents.
• Add, delete, update, and correct the data
• Ex Ms-Access.

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Types of Personal Application Software

• Word processing allows the user to manipulate
  text rather than just numbers.
• Many word processors contain many productive
  writing and editing features.
• A typical word processing software package
  consists of an integrated set of programs
  including an editor program, a formatting
  program, a print program, a dictionary, a grammar
  checker, and integrated graphics, charting, and
  drawing programs.

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Types of Personal Application Software

• Desktop publishing represents a level of
  sophisticated beyond regular word processing.
• In the past, newsletters, announcements,
  advertising copy had to be laid out by hand and
  typeset.
• Design and print newsletters, brochures, manuals,
  and books.

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Types of Personal Application Software

• Graphics Graphics software allow user to create,
  store and display or print charts, graphs, maps
  and drawings.
• It enables users to absorb more information more
  quickly and to spot relationships and trends in
  data more easily.
• Ex Ms-Power Point (Helps convert numeric data
  into graphic displays. Presentation graphics
  software)

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Types of Personal Application Software

• Groupware it facilitates communication,
  coordination, and collaboration among people.
• Helps workgroups and teams work together to
  accomplish group assignments.
• Combines a variety of software features and
  functions
• E-mail
• Discussion groups and databases
• Scheduling
• Task management
• Audio and videoconferencing
• Data sharing
• Ex Novells Group Wise, Oracles InterOffice.

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Software Suits

• Suites are a number of productivity packages
  bundled together
• Microsoft Office
• Lotus SmartSuite
• Corel WordPerfect Office
• Sun StarOffice

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Software Suites (continued)

• Advantages of suites
• Cost
• Similar graphical user interface
• Share common tools
• Programs are designed to work together
• Disadvantages of suites
• Large size
• Many features never used by many end users

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Web Browsers

• Key software interface to the hyperlinked
  resources of the World Wide Web and the rest of
  the Internet. Easy-to-use software tools for
  displaying Web and the other Internet resources.
• Internet Explorer
• Netscape Communicator

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Programming Languages

• Programming languages allow people to tell
  computers what to do and are the means by which
  software systems are developed.

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GENERATIONS OF PROGRAMMING LANGUAGES
1st. Since 1940s. MACHINE LANGUAGE binary
code 2nd. Since early 50s. ASSEMBLER LANGUAGE
mnemonics for numeric code 3rd. Since mid 50s.
HIGH-LEVEL LANGUAGES 4th. Since late 70s.
FOURTH-GENERATION LANGUAGES
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Machine language

• Lowest-level computer language.
• It is considered the first-generation language.
• Composed of binary codes unique to each computer
• Requires the programmer to write all program
  instructions in the 0s and 1s of binary code.
• It is extremely difficult to understand, and use
  by programmers. Very slow.
• As a result, increasingly more user-friendly
  languages have been developed.

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Assembler language

• Next level up from machine language.
• It is still considered a lower-level language but
  is more user-friendly.
• Requires language translator programs called
  assemblers
• Allows a computer to convert the instructions
  into machine instructions
• Frequently called symbolic language

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High-level languages

• Third generation
• Uses instructions, called statements, that use
  brief statements or arithmetic expressions
• Uses translator programs called compilers or
  interpreters
• Syntax and semantics

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HIGH-LEVEL LANGUAGES

• FORTRAN (FORmula TRANslator) Scientific,
  Engineering applications
• COBOL (COmmon Business Oriented Language)
  Predominant for transaction processing
• BASIC (Beginners All-purpose Symbolic Instruction
  Code) General purpose PC language

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HIGH-LEVEL LANGUAGES

• PASCAL Used to teach structured programming
  practices. Weak in file handling, input / output
• C Powerful PC Language for developing
  applications. Efficient execution cross
  platform.

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FOURTH GENERATION LANGUAGES (4GL)

• Can be used by non-technical users to carry out
  specific functional tasks.
• Called NONPROCEDURAL.
• Can develop applications quickly
• These languages greatly simplify and accelerate
  the programming process.

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FOURTH GENERATION LANGUAGES (4GL)

• Examples of the 4GLs are query languages (SQL),
  report generators (RPG III), graphics languages
  (Visual C) and PC software tools (WordPerfect,
  Ms-Access).

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Object-oriented programming languages

• Based on the idea of taking a small amount of
  data and the instructions about what to do with
  that data and putting both of them together into
  what is called an object.
• Easier to use.
• Creates reusable code.
• Reduces time and cost of writing software.

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OBJECT-ORIENTED PROGRAMMING

• JAVA Sun Microsystems OBJECT-ORIENTED
  PROGRAMMING LANGUAGE
• Applet tiny program to execute small function
• Applets downloaded from network
• Run on any computer operating system
• Designed for real-time, interactive, Web-based
  network applications

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OBJECT-ORIENTED PROGRAMMING

• HTML (Hypertext Markup Language)
• A page description language that creates
  hypertext or hypermedia documents
• HTML is very easy to use.
• The standard language the World Wide Web uses for
  creating and recognizing hypertext documents.