Software Technology

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• Software Technology

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Points

• Compile process
• Application Systems
• System software
• Operating system/network access
• Utilities
• User interface environments
• Languages development tools (CASE)
• Databases

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Software Classification
APPLICATION
DEVELOPMENT
SYSTEM
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Primacy of Software

• Software, not hardware, determines the actions
  of a computer.
• Source Code program code intended to be written
  or read by people
• Machine Code programs in binary form using the
  computer instruction set

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How Software Works Step 1
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How Software Works Step 2
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How Software Works Step 3
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How Software Works Step 4
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Computer Languages

• Language Translation Method
• interpreter
• compiler
• Level of Abstraction
• second-generation
• third-generation
• fourth-generation
• Procedural Versus Nonprocedural
• Command/Data or Object-Oriented

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Generations

• First - Machine language
• Second - Assembly language
• Third - High-level languages (COBOL, FORTRAN,
  BASIC, C,C, Java, Ada)
• Fourth - 4GL (Focus, RAMIS, SQL)
• Fifth - Natural languages

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System Software

• Operating System
• provide an easier user interface
• manage system resources
• support multiple tasks and multiple users
• Systems Utilities

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Types of Interfaces

• Command- oriented interfaces
• prompt the user to type in a command that is
  translated into an instruction for the program to
  follow
• Menu- driven interfaces
• offer a list of choices or options, called a
  menu, as a way of letting a user choose from
  several different commands or functions

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Types of Interfaces

• Natural Language interfaces
• allow the user to input simple English statements
  that are translated into commands by the program.
• Graphical User Interfaces (GUIs)

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Operating System Functions

• Booting
• Housekeeping Tasks (formatting, coordinating)
• Managing Computer Resources (memory and devices)
• Managing Files (i.e., copy, erase)
• Managing Tasks

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OS Components
APPLICATION PROGRAMS
MEMORY
SYSTEM PROGRAMS (COMPILERS, etc.)
OPERATING SYSTEM
KERNEL
MACHINE LANGUAGE
MICROPROGRAMMING
ROM
PHYSICAL EXECUTION
CPU
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Types of Tasks

• Multitasking
• 2 or more programs
• user concurrently on same computer with same CPU
• Multiprogramming
• 2 or more programs
• multiuser operating system, shared CPU
• Multiprocessing
• multiple CPUs

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Memory Management
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Virtual Memory
FRAME NUMBER OFFSET
PAGE NUMBER OFFSET
PAGE TABLE
PAGE TABLE
PAGE TABLE
Page Frames
Pages
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Addresses

• Physical address actual memory location.
  NEEDED BY THE CPU
• Relative address offset from a reference
  physical address. NEEDED BY THE OPERATING SYSTEM
• Logical address address within a programmed
  unit (e.g. page). NEEDED BY APPLICATION PROGRAMS

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Systems Software

• Network Operating Systems
• directing instructions
• communicating with the network
• security services
• directory services
• device management

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Workstation Functions
APPLICATION
REDIRECTION
OPERATING SYSTEM
NETWORK INTERFACE
NIC
CPU
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Client Functions

• Application execution
• Fat and thin clients
• Network access
• Network software and hardware (NIC)
• Application software maintenance
• Remote resources

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Client NOS Software
Directs requests from the Client to the network
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Server Functions

• Shared resources
• File and print services
• Application management
• Network operating system
• Access to the network
• Higher layer functions
• Security
• Backup and professional support

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Server NOSSoftware

• Manages central
• services and external
• interfaces
• Directory services
• Translation protocol

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Access

• Centralized
• Legacy applications
• Client/Server
• Scalability
• Ownership
• Management
• Web
• JAVA, etc.

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Centralized Model
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Client/Server Model

• Two-tier
• Three-tier
• Multitier

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Web Model
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Mindshare
Ownership
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Client Focus
Bill Gates
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Net Focus
Larry Ellison
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Issue Desktop Ownership

• Who controls the desktop
• Standardization and version management
• Distribution
• Payment for access

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Application Software

• Make or Buy
• Integrated Solutions or Best of Breed
• Preparing for the Year 2000
• Application Software Life Cycle
• SDLC
• Rapid Application Development

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Development Environments

• Desktop Systems
• Code Generators
• Development Systems and CASE Tools
• Middleware and other user environments

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Integrated Solutions (ERP)
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Year 2000

• Replace Existing Software with Year 2000
  Compliant ERP Products
• Repair Legacy Products
• Use Automated Tools
• Build Software that Will Intercept and Convert
  Dates as They Are Entered, Stored, or Output

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Software Acquisition

• Create
• Purchase
• Product
• Contract development
• Lease
• Seat
• Station

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