Transcript Computer Software 02/2/00

Software
Technology
Points
Compile process
Application Systems
System software
Operating system/network access
Utilities
User interface environments
Languages & development tools (CASE)
Databases
Software Classification
APPLICATION
DEVELOPMENT
SYSTEM
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
How Software Works:
Step 1
How Software Works:
Step 2
How Software Works:
Step 3
How Software Works:
Step 4
Computer Languages
Language Translation Method
interpreter
compiler
Level of Abstraction
second-generation
third-generation
fourth-generation
Procedural Versus Nonprocedural
Command/Data or Object-Oriented
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
System Software
Operating System
provide an easier user interface
manage system resources
support multiple tasks and multiple users
Systems Utilities
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
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 (GUI’s)
Operating System
Functions
Booting
Housekeeping Tasks (formatting,
coordinating)
Managing Computer Resources
(memory and devices)
Managing Files (i.e., copy, erase)
Managing Tasks
OS Components
APPLICATION PROGRAMS
SYSTEM PROGRAMS
(COMPILERS, etc.)
MEMORY
OPERATING SYSTEM
MACHINE LANGUAGE
KERNEL
MICROPROGRAMMING
ROM
PHYSICAL EXECUTION
CPU
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
Memory Management
Virtual Memory
PAGE NUMBER +
OFFSET
PAGE
TABLE
FRAME NUMBER +
OFFSET
PAGE
TABLE
PAGE
TABLE
Pages
Page Frames
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
Systems Software
Network Operating Systems
directing instructions
communicating with the network
security services
directory services
device management
Workstation Functions
REDIRECTION
APPLICATION
OPERATING
SYSTEM
CPU
NETWORK
INTERFACE
NIC
Client Functions
Application execution
Fat and thin clients
Network access
Network software and hardware (NIC)
Application software maintenance
Remote resources
Client NOS
Software
Directs requests
from the Client
to the network
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
Server NOS
Software
Manages central
services and external
interfaces
•Directory services
•Translation protocol
Access
Centralized
Legacy applications
Client/Server
Scalability
Ownership
Management
Web
JAVA, etc.
Centralized Model
Client/Server Model
Two-tier
Three-tier
Multitier
Web Model
Mindshare
Ownership
Client
Focus
Bill Gates
Net Focus
Larry Ellison
Issue: Desktop Ownership
Who controls the desktop
Standardization and version management
Distribution
Payment for access
Application Software
Make or Buy
Integrated Solutions or Best of Breed
Preparing for the Year 2000
Application Software Life Cycle
SDLC
Rapid Application Development
Development Environments
Desktop Systems
Code Generators
Development Systems and CASE Tools
Middleware and other user environments
Integrated Solutions (ERP)
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
Software Acquisition
Create
Purchase
Product
Contract development
Lease
Seat
Station
1+1=2