COMPUTER SOFTWARE

Section 2 “System Software: Computer System Management ”

CHAPTER 4

Lecture-6/ T. Nouf Almujally

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2 System Software

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System Software

SystemManagement

Programs

System Development

Programs

Manages hardware, software, network, and data resources of computer systems

Operating systems, network management programs, database management systems,

system utilities

Helps users develop IS programs and procedures, and then prepare them

for processing

Includes Programming language translators and editors, CASE, and programming tools

Consists of programs that manage and support a computer system and its information processing activities.

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Interface Between End Users & Computer

5 System Management Programs

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Operating Systems

Integrated system of programs that…

Provides support services as the

computer executes

application programs

Manages the operations of the

CPU

Controls the input/out, storage

resources, and activities of the

computer system

The operating system must be loaded and activatedbefore other tasks can be accomplished

Examples of Popular Operating Systems :Microsoft Windows, Unix, Linux and MAC OS X

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Operating System Basic Functions

• Command-driven

• Menu-driven• Graphical User

Interfaces (GUI)

Multitasking: is a task management approach

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OS User interface Defined as the part of the information system

through which the end user interacts with the system

Command-driven interface: • The computer users have to input the command every time• (e.g., MS-DOCS).

Menu-driven interface: • The computers users use the menu to• execute the command instead of typing it in.

Graphical User Interface (GUI): • Defined as the part of an operating system users interact with that

uses• graphic icons and the computer mouse to issue commands and make• selections. The user uses a mouse to control the computer.

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Resource Management• An operating system uses a variety of resource

management programs to manage the hw and network resources of a computer system.

• Including CPU, memory, secondary storage devices, input/output peripherals .

• Common functions:• Keeping track of where data and programs are

stored• Subdividing memory; providing virtual memory

capability • E.g. Memory Management Program

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File Management• Control the creation , deletion, and access to files

of data and programs.• Keep track of physical location of files on

magnetic disks and other secondary storage devices.

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Task management• Help accomplish the computing tasks of end

users.• The program control:

• Which task gets access to CPU• For how much time• Allocate a specific slice of CPU time to a particular

task.

• Multitasking: is a task management approach, allow for several computing tasks to be performed in a simultaneous fashion .

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Other System Management Programs

• Database management systems chapter 5• Network management Programs chapter 6

This figure compares several types of system software offered by IBM and its competitors

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Other System Management Programs

• Other system management software are marked as separate programs or included as part of an operating system:

• Utility programs (or utilities):• Programs like Norton utilities perform various housekeeping

functions, includes data backup, virus protection, data compression, etc.

• Performance Monitors:• Programs that monitor and adjust computer system to keep them

running efficiently.

• Security Monitors:• Monitor and control use of computer systems and provide warning

messages and record unauthorized use of resources.

14 System Development Programs

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Programming Languages• Allows a programmer to develop the sets of instructions

that constitute a computer program.

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Machine Languages

First Generation Languages

The most basic of programming languages

All program instructions had to be written using binary codes

Requires specific knowledge of theinternal operations of the CPU being used

Must specify the storage location for everyinstruction and item of data used

Difficult to work with, and error prone

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Assembler Languages

Second Generation Languages

Developed to reduce difficultiesin writing machine language programs

Uses “assemblers” to convert the programsinto machine instructions

Symbols used to represent operation codesand storage locations

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High-Level Languages

Third Generation Languages

Uses brief “statements” or arithmetic expressions

Statements translated into machine languageby compilers or interpreters

Less efficient than assembler language andrequires greater translation time

Machine-independent

Examples: BASIC, COBOL, FORTRAN

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Fourth-Generation Languages

Fourth-Generation Languages

Variety of programming languages that arenonprocedural and conversational

Programmers specify the result wanted;the computer determines the sequence of

instructions that accomplish the result

Simplifies the programming process

Natural language; very close to English or human languages

Sometimes called fifth-generation (5GLs)

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Object-Oriented Languages• Combines data elements and the procedures that will be

performed upon them into objects.E.g., data about a bank account and the procedures performed on it, such as interest calculations

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Object-Oriented Languages

Easier to use and more efficient for graphics-oriented user interfaces

Most widely used software development languages

Reusable: can use an object from one application in another application

Examples: Visual Basic, C++, Java

Most object-oriented languages provide a GUI that supports visual programming

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Web Languages

HTML A page description language that creates hypertext documents for the Web

XML Describes Web page content by applying identifying tags or contextual labels

to the data

Java Object-oriented programming language that is simple, secure, and platform independent

Java applets can be executedon any computer

• HTML, XML and Java are three programming languages that are important tools for building multimedia web pages, web sites and web-based applications.

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Programming Software

Language Translator Program : is a program that translate instructions written in programming languages into machine language that computer can execute.

Assembler

Translates assembler language

statement

Compiler

Translates high-level language

statements

Interpreter

A compiler that translates and executes each

statement ina program,

one at a time instead of first producing a complete

machine language programs,

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Programming Tools• Language translators have always provided some

editing and diagnostic capabilities to identify programming errors or bugs.

• However, most software development programs now include powerful graphics-oriented programming editors and debuggers.

• These programming tools help programmers identify and minimize errors while they are programming.

• An essential part of widely used programming languages like Visual Basic, C++ and Java.

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Questions ..

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Read from Chapter 4 (Section 2)

Resources..