Type of Software

There are two main types of software They are

System software Application software

Hardware

System Software (OS)

Application Software (Word, Excel)

System Software

System software is computer software designed to operate the computer hardware and to provide a platform for running application software

System software also provides services to computer users and application programs

Examples of system software are: operating system, device driver and utility programs

Operating System Printer Driver Hard Disk Analyzer

Operating System Function I

Provide user interface (text interface and/or graphical user interface)

Execute application (automate the process to run a program, loading program into main memory, transfer control to CPU, etc)

Manage CPU time (allocate CPU time to different processes to achieve multitasking)

Multitasking refers to the ability to run two or more tasks at the same time

Memory management (allocate memory to different processes so as to maximize system performance)

Operating System Function II

Manage I/O (peripheral) devices such as keyboard, mouse, monitor, network interface card, etc

Provide system accounting service (logging, CPU and /or disk usage)

Provide system security (by using user name and password)

Application Program

Application program is designed to solve a particular kind of problem

Examples of application program: Word processor (Word) Spreadsheet (Excel) Graphic Editor (Photoshop)

Software (Rights)

• Software can be classified according to the rights that come with the software

• There are 4 main types of software in this category:

– Proprietary software

– Shareware

– Freeware

– Open source software

Proprietary Software

• Proprietary software is computer software that gives the legal right to use the software to customer under restrict conditions.

• Conditions include:

– Re-distribution is not allowed

– Re-sell is not allowed

– Modification is not allowed, etc

– Example:

Shareware

• Share is similar to proprietary software except that it can be downloaded from the internet with a trial period

• During the trial period, customers can use the software for free

• Customer should (must?) pay for the software if he/she wants to continue to use the software after the trial period

• Examples:

Winzip (Utility) Window Media Player (Application)

Freeware

• Freeware is completely free of charge

• It can be downloaded from the Internet

• However, users are only given the right to use the software, users are not allowed to modify and/or resell the software

• Example:

AntiVirus Utility

Open Source Software

• Open Source Software gives all rights to users

• Users can get the source code which can be used to modify the software

• Users can re-distribute open source software (or even re-sell it!)

• Example:

Office Suite Graphic Editor

Mode of Operation

• Mode of operation refers to how computer system reacts to input data

• Batch Processing vs Real-time Processing

• When data are accumulated and processed only at a certain time (say once a week or once a month), this type of processing is called batch processing

• Example application:

Electricity Bill,Credit Card Bill, etc

Real-time Processing

• In real-time processing, data must be processing within a very short period of time

• Example application:

Ticker Booking(Air ticket,Cinema ticket, etc)

Interactive Processing

• Interactive processing refers to the processing of data that requires feed back from users

• Example:

ATM (automatic teller machine)

-It works interactively

(real-time!)

-Question:

Are all real-time processes must be interactive?