Introduction to Information Technol

Introduction to Information Technology
Chapter 2:
Computer Software:
Systems and Application Software

Chapter Preview
• In this chapter, we will study:
– Systems Software
– Application Software
– How software applications are developed
– Outline the overall evolution and importance of
programming languages and clearly differentiate among
the generations of programming languages.
– Identify several key software issues and trends that
have an impact on organizations and individuals

The Importance of Software in
Business....

AN OVERVIEW OF SOFTWARE
• Computer programs: are sequences of
instructions for the computer
• Documentation describes the program
functions to help the user operate the
computer system

The Software Crisis
• New software applications
cannot be developed fast
enough to:
– Keep up with dynamic business
environment
– Keep pace with rapid hardware
advances

The Software Crisis (continued)
• In addition to new application development,
existing software must also be maintained
(80% IT personnel effort towards maintenance).
• Increasing complexity leads to the increased
potential for “bugs.”
• Testing and “debugging” software is
expensive and time-consuming.

Software Fundamentals
• Some basic terms…
– Computer programs - sequences of instructions for the
computer
– Stored program concept – instructions written in
programs are stored and executed by CPU when needed
– Programming - process of writing (or coding) programs
– Programmers - individuals who perform programming

Software Fundamentals (continued)
• Systems Software
– Instructions that
manage the
hardware resources
• Application Software
– Instructions that
perform specific user
tasks

Contd...

System Software
• System software is software that:
– Controls and supports the computer system’s
activities
– Supports application software by directing the
computer’s basic functions
– Facilitates program development, testing, and
debugging
– Is independent of any specific type of application

Systems Software (continued)
• System Control
Programs
– Control use of all system
resources (hardware,
software, data); operating
system
• System Support
Programs
– Specialized support
capabilities

Operating Systems
• An operating system (OS) is a set of programs
that controls the computer hardware and acts as
an interface with applications

Operating Systems (Contd...)
• The various combinations of OSs, computers,
and users include the following:
– Single computer with a single user. This
system is commonly used in a personal computer
or a handheld computer that allows one user at a
time
– Single computer with multiple users. This
system is typical of larger, mainframe computers
that can accommodate hundreds or thousands of
people, all using the computer at the same time

Contd...
• The various combinations of OSs, computers,
and users include the following:
– Multiple computers. This system is typical of a
network of computers, such as a home network
with several computers attached or a large
computer network with hundreds of computers
attached around the world
– Special-purpose computers. This system is
typical of a number of computers with specialized
functions, such as those that control sophisticated
military aircraft, and some home appliances

Basic Function of OS
• Performing common computer hardware
functions
• Providing a user interface and input/output
management
• Providing a degree of hardware independence
• Managing system memory
• Managing processing tasks
• Providing networking capability
• Controlling access to system resources
• Managing files

Common Computer Hardware Functions
• Get input from the keyboard or another
input device
• Retrieve data from disks
• Store data on disks
• Display information on a monitor or printer

User Interface and Input/Output Management
• Most of important functions of OS
• Allows to access and command computer

Hardware Independence
• To run, applications
request services from the
OS through a defined
application program
interface (API)
• Programmers can use
APIs to create application
software without having to
understand the inner
workings of the OS

Memory Management
• Controls how memory is accessed and
maximizes available memory and storage
• To execute program instructions
effectively and to speed processing
• One way to increase the performance of
an old computer is to upgrade to a newer
OS and increase the amount of memory

Networking Capability
• Computers can join together in a network
to send and receive data and share
computing resources.
• Sharing Internet connections, printers,
storage, and data

Hasil (Bahasa Indonesia) 1:

Pengenalan teknologi informasiBab 2:Perangkat lunak komputer:Sistem dan aplikasi perangkat lunakBab Tinjauan• Dalam bab ini, kita akan mempelajari:-Systems Software-Aplikasi perangkat lunak-Bagaimana aplikasi perangkat lunak yang dikembangkan-Garis besar evolusi dan pentingnya keseluruhanbahasa pemrograman dan jelas membedakan antaragenerasi bahasa pemrograman.-Mengidentifikasi beberapa isu kunci perangkat lunak dan tren yangberdampak pada organisasi dan individuPentingnya perangkat lunakBisnis...IKHTISAR DARI PERANGKAT LUNAK• Program komputer: urutanpetunjuk untuk komputer• Dokumentasi menjelaskan programfungsi untuk membantu pengguna beroperasisistem komputerKrisis perangkat lunak• Aplikasi perangkat lunak barutidak dapat dikembangkan cepatcukup untuk:-Menjaga dengan bisnis yang dinamislingkungan-Mengikuti dengan cepat hardwarekemajuanKrisis perangkat lunak (lanjutan)• Selain pengembangan aplikasi baru,perangkat lunak yang ada juga dapat dipertahankan(80% upaya personil TI untuk pemeliharaan).• Meningkatnya kompleksitas mengarah ke peningkatanpotensi untuk "bug."• Pengujian dan "debugging" perangkat lunak adalahmahal dan memakan waktu.Dasar-dasar perangkat lunak• Beberapa istilah dasar...-Komputer program - urutan petunjuk untukkomputer– Konsep program disimpan-instruksi yang ditulis dalamProgram disimpan dan dijalankan oleh CPU ketika diperlukan-Pemrograman - proses penulisan (atau coding) program– Programmers - individuals who perform programmingSoftware Fundamentals (continued)• Systems Software– Instructions thatmanage thehardware resources• Application Software– Instructions thatperform specific usertasksContd...System Software• System software is software that:– Controls and supports the computer system’sactivities– Supports application software by directing thecomputer’s basic functions– Facilitates program development, testing, anddebugging– Is independent of any specific type of applicationSystems Software (continued)• System ControlPrograms– Control use of all systemresources (hardware,software, data); operatingsystem• System SupportPrograms– Specialized supportcapabilitiesOperating Systems• An operating system (OS) is a set of programsthat controls the computer hardware and acts asan interface with applicationsOperating Systems (Contd...)• The various combinations of OSs, computers,and users include the following:– Single computer with a single user. Thissystem is commonly used in a personal computeror a handheld computer that allows one user at atime– Single computer with multiple users. Thissystem is typical of larger, mainframe computersthat can accommodate hundreds or thousands ofpeople, all using the computer at the same timeContd...• The various combinations of OSs, computers,and users include the following:– Multiple computers. This system is typical of anetwork of computers, such as a home networkwith several computers attached or a largecomputer network with hundreds of computersattached around the world– Special-purpose computers. This system istypical of a number of computers with specializedfunctions, such as those that control sophisticatedmilitary aircraft, and some home appliancesBasic Function of OS• Performing common computer hardwarefunctions• Providing a user interface and input/outputmanagement• Providing a degree of hardware independence• Managing system memory• Managing processing tasks• Providing networking capability• Controlling access to system resources• Managing filesCommon Computer Hardware Functions• Get input from the keyboard or anotherinput device• Retrieve data from disks• Store data on disks• Display information on a monitor or printerUser Interface and Input/Output Management• Most of important functions of OS• Allows to access and command computerHardware Independence• To run, applicationsrequest services from theOS through a definedapplication programinterface (API)• Programmers can useAPIs to create applicationsoftware without having tounderstand the innerworkings of the OSMemory Management• Controls how memory is accessed andmaximizes available memory and storage• To execute program instructionseffectively and to speed processing• One way to increase the performance ofkomputer lama adalah untuk meng-upgrade ke yang lebih baruOS dan peningkatan jumlah memoriKemampuan jaringan• Komputer dapat bergabung dalam jaringanuntuk mengirim dan menerima data dan berbagisumber daya komputasi.• Berbagi koneksi Internet, printer,Penyimpanan, dan data