Lecture 09

1

CS1010 Introduction to Computing

LEARNING GOALS FOR TODAY

• _{To discuss the role of software in computing}

systems.

• _{To learn to differentiate among software}

belonging to the system and application

categories.

• _{To learn about application software.}

• _{To become familiar with various software used}

e.g.

– _{Scientific/Engineering/Graphics} – _Business

– _Productivity

– _{Entertainment}

COMPUTER SOFTWARE

• _{How to differentiate between hardware and software?}

• _{Hardware is a physical part for a computing} environment. The part which you can touch.

• _{Software is runs that hardware. The instructions given} to hardware is what we called software also known as Computer Program.

• _{The hardware needs software to be useful, and vice}

MACHINE LANGUAGE

• _{The language of computer that it can understand and} execute is called Machine Language.

• _{Machine language is a}

lowest level language.

• _{Machine language is very easy but not for humans}

rather for computers. To understand and write

LANGUAGE TRANSLATORS

• _{Human programmers write programs in a}

language that is easy to understand for them.

• _{They use language translators to convert that}

program into machine language.

– _Compiler

– _Interpreter

• _{In future lecture we discuss on language}

SOFTWARE DEVELOPMENT

• _{Develop large scale, complex}

programs/software is not so easy task.

• _{It does not include just coding, many other}

features are also included.

• _{Analysis of Software Development:}

• _{You just spend 15 % of your time in coding, rest}

THE SOFTWARE DEVELOPMENT

PPROCESS

Concept & Feasibility

Concept & Feasibility

• _{Concept & Feasibility:}

Will this software will be useful, means think of a feasibility. How many money will required to develop this complex

software. What will be the benefit of development. Is cost is higher than benefit.

• _{User Requirement:}

Next phase is requirement gathering of user.

In this phase many questionnaire is asking from the potential user, what type of features, processing they need.

• _{Developer Specification:}

• _Planning:

In planning phase, what is the nature of this s/w, how many work force is required? How many resources required, and how much time is required.

• _Design:

For a large scale, complex software, you don’t write a single program, you divide it in many small modules and develop individually and before that design individually.

• _{Implementation:}

MAJOR TYPES OF SOFTWARE

• _{Two major types of software:}

– _{System software}

SYSTEM & APPLICATION SOFTWARE

which user can not see.

• _{System software interact with computer hardware.}

• _{Application software talks to the hardware through system}

software.

• _{Through Application programs user interact with computer.}

• _{Usually application software interact with operating system}

HARDWARE

OPERATING SYSTEM DEVICE DRIVER

Utility _TranslatorLanguage Scientific_Apps. Business_Apps. Productivity _Apps. Entertainment _Apps.

System Software

System software are programs that ..

• _{Control the overall operation of the computer.}

– _{Operating system}

• _{Interact directly with hardware.}

– _{Device drivers}

• _{Perform system management & maintenance.}

– _Utilities

• _{Are used to develop or maintain other programs.}

Types of System Software

• _{Operating System}

• _Firmware

• _Utilities

• _{Language Translators}

OPERATING SYSTEM

• _{Operating System are working in background.}

• _Example:

– _{How the files are transferring from memory to hard disk.} – _{How you see images on screen.}

– When you typed on keyboard, they produce results.

– _{When microprocessor perform any particular task.}

• _{The key factor about operating system is that they interact}

directly with hardware.

• _{Types of OS:}

FIRMWARE

• _{Firmware is software that is embedded in a piece of} hardware.

• _{Firmware are programs running on devices used to} control it.

• _Example:

– _{ROM (when computer is turned on, it’s the first program}

that always executes.)

– _{On IBM-compatible PC’s, the startup program is known as} BIOS.

UTILITIES

• _{Utility software is system software designed to help analyze,}

configure, optimize or maintain a computer.

• _{Functions performed by Utilities:}

A utility program performs a specific task related:

– _{Management of Computer Functions.} – _Resources

– _{Memory Management,} – _{Virus Protection}

– _{File Compression.}

• _Example:

– _{Anti virus software}

LANGUAGE TRANSLATORS

• _{Language translators are programs that take code in high}

level language and translate it into a low-level language

that is easily understood by microprocessor.

• _{Language translators are of two types:}

– _{Compiler: the program written in a high level language}

translates into machine language in one go. The translated code is then used by the microprocessor whenever the program

needs to run.

– _{Interpreter: translates the high level language program one}

COMPILARS AND INTERPRETERS

• _{Programs written in a higher language must be}

converted into machine language

Source code

Compiler Interpreter

Object code

DEVICE DRIVERS

• _{Device drivers connect software to hardware.}

• _{They are computer programs that is intended to allow another}

program(typically OS) to interact with a hardware device.

• They sit between hardware and software.

• Think of a driver as a manual that gives the OS (e.g. windows)

instructions on how to use a particular piece of hardware.

• Device driver software converts generally input/output

APPLICATION SOFTWARE

• _{Application software are programs that interact}

directly with the user for the performance of a certain type of work. (generally application s/w talks with hardware through system software)

• _{Scientific/Engineering/Graphics Software}

• _{Business Software}

• _{Productivity Software} • _{Entertainment Software}

INTERFACE HARDWARE - USER

• _{operating system: OS} • _{support: system utilities} • _{development: compilers}

Application software

• _packages

APPLICATION SOFTWARE

Classification According to the

Mode

• _{Interactive-mode}

– _{The user runs the program on the computer and keeps}

on interacting with the computer while the program runs

– _{Example: Word processor} • _Batch-mode

– _{The user starts the program and the computer processes} the provided data and produces results without any

further intervention of from the user

• _{Scientific/Engineering/Graphics Software}

• _{Business Software}

• _{Productivity Software} • _{Entertainment Software}

Scientific/Engineering/Graphics Apps

• _{Key feature: Intense floating-point calculations}

• _{Scientific/engineering/mathematical apps}

– _{Computers initially were designed just to run them} – _{Generally designed for specialists}

– _{Rudimentary UI’s (Not a user friendly interface)}

Scientific SW

– _{Deforestation and effect on green-house gases} • _{Simulation of artificial systems}

– _{NeuralWare (Simulator for artificial neural networks)} – _{Thermo-nuclear explosions}

• _{Mathematical computation packages}

Engineering SW

– _{AutoCAD (design architecture drawings)} – _{SPICE (design electronic circuits)}

– _{Virtual wind tunnels (e.g. Boeing 777)}

• _{Computer-aided manufacturing (CAM)}

• _{Industrial control SW (A SW to control different}

kinds of plants e.g. chemical plant)

Graphics & Animation SW (1)

Two types:

1. Vector graphics

• _{Treats everything that is drawn as an object}

• _{Objects retain their identity after they are drawn} • _{These objects can later be easily moved, stretched,}

duplicated, deleted, etc

• _{Are resolution independent} • _{Relatively small file size}

• _{Example: MS Visio, Corel Draw, Flash}

Graphics & Animation SW (2)

2. Bit-mapped or raster graphics

• _{Treats everything that is drawn as a bit-map}

• _{If an object is drawn on top of another, it is difficult to} move just 1 of them while leaving the other untouched • _{Changing the resolution often requires considerable}

touch-up work

• _{Relatively large file size}

Business Applications

• _{Most of the SW being developed today belongs to}

this category

• _{SW that is required to run most any sort of biz:} – _Payroll

– _{General ledger} – _{Order entry}

– _{Accounts receivable & accounts payable} – _{Inventory control}

E-Commerce Software

• _{Interactive SW(customer through website interact}

with you, and interact with computer not with a sales person).

• _{E-Commerce SW is Custom Built.}

• _{Key requirements:}

– _Reliability

– _Security

ERP (Enterprise Resource Planning) SW

• _{Very large scale, complex & expensive SW}

• _{Ties together all key activities & major systems of an}

organization into a single SW system

• _{Key benefit: Optimization of the business processes}

of an organization as a single system instead of many loosely-related stand-alone systems

DSS (Decision Support Systems) SW

• _{Sometimes also called “expert systems”}

• _{Many times are based on a branch of computer}

science called “artificial intelligence”

• _{This category of SW is designed to help business}

Productivity SW

• _{Most popular category in terms of licenses sold}

• _{Common features}

– _{Ability to simplify, automate everyday business tasks} – _{Highly interactive and user-friendly design}

– _{Designed to run on PC’s}

– _{Most users do not use 90% of the SW features} • _{Popular productivity SW}

Word Processors

• _{Initially designed as a replacement for the typewriter} • _Automation

– _{Automatic end-of-line soft carriage return}

– _{Style sheets}

– _{Table of contents & index}

– _{Spelling & grammar checking}

• _{Two approaches: WYSIWYG (e.g. Word, WordPerfect, Star)} or NON-WYSIWYG (HTML, LaTeX)?

Web Page Development SW

• _{Web pages can be developed using a simple} plain-text editor like the “notepad”, but more efficient, easy-to-use HTML editors can make the process quicker

• _{Some of them are WYSIWYG (i.e. you don’t really} need to know any HTML to use them), others are not, while some provide both types of interfaces (DreamWeaver)

• _{Most popular word processors now come with a}

Spreadsheet SW (1)

• _{Is used for automating engineering, scientific, but in}

majority of cases, business calculations

• _{A spreadsheet - VisiCalc - was the first popular}

application on PC’s.

• _{It helped in popularizing PC’s by making the task of} financial-forecasting much simpler, allowing

Spreadsheet SW (2)

• _{Consist of cells arranged in rows and columns}

• _{Each cell may contain numeric values, text or}

formulas

• _Automation

Presentation Development SW

• _{Used to prepare multimedia material for lectures &}

presentations to display key points, graphics,

animation, or video with the help of multimedia

projectors

• _{Have replaced acetate films (slides) that were used}

with over-head projectors

• _{Key advantage over acetate slides:} – _{Easy to modify}

– _{Can be sent electronically}

Small-Scale Databases SW (1)

• _{Easy to use applications designed for efficient}

storage and fast and easy retrieval of data

• _{That data may be in the form of numbers, text, or}

Small-Scale Databases SW (2)

“relational” database model, the data-basing

function was performed using what is called the

“flat-file” model

• _{That model is not very efficient for storing and}

searching in large databases

• _{A database consists of a file or a set of files.} Information in these is stored in the form of

records, and the records are further subdivided into

Productivity SW Suites

• _{A set of stand-alone productivity applications}

designed to work easily with each other

• _{Share a common UI}

• _{Are available as a bundle along with additional}

useful utilities

• _{Examples: MS Office, Corel WordPerfect Office,}

Lotus SmartSuite, Star Office

• _{SW Suites for other app areas are available as well,}

Entertainment SW

Key feature: Simple, intuitive, many times social UI’s

• _{The user is generally assumed to know nothing}

about computers

Music & Video Players

• _{Music players (WinAmp)}

• _{Video/Music players (Real player, Windows Media}

player, QuickTime player)

• _{The Web Browsers can also display video,}

animation, and play music with the help of helper

Games

– _{Educational (especially for toddlers)}

– _{Strategy/Simulation (e.g. SimCity)}

– _Sports

– _{Shoot’em ups}

• _{The saddest aspect: You do not need any}

opponents or partners to play computer games

Educational SW

• _{Category with probably the highest growth rate}

• _{Current focus on augmenting traditional training}

and education methods, but it is shifting towards

Electronic Encyclopedias

• _{Great resource of useful information presented in a}

very interesting format

• _{Superior to the paper-based version because:}

– _{Access speed is dramatically higher}

– _{Can contain animation and sound}

On-Line Learning

• _{With time, the VU Web site will become more and}

more focused on interactive online learning

• _{The Website of our textbook “Understanding}

Computers” is an example of an on-line learning Website

• _{Key features of good online learning SW:}

Interactive CD’s

• _{Same as on-line learning, but through a CD}

instead of a Web site

• _{Key advantage:}

Attributes of Good Application Software

• _{User Interface}

– _Consistent

– _Intuitive

– _Configurable

– _{Adapts to the users need}

• _{Has a tutorial and a complete help manual}

ANOTHER WAY OF

ANOTHER WAY OF CLASSIFYING SOFTWARE

• _{Shrink-Wrapped Software}

 _{You can just go to shop and buy it.}

 _{They are built in such a way that it is useful for} many different users in many different ways.

• _Example:

• _{Custom-built Software}

 _{You have to find someone who can develop it for} you.

 _{These software are built for a particular}

organization to fulfill the needs of the particular organization

• _Example:

DIFFERENCE

• _{Another thing that distinguish shrink wrapped}

WHO OWNS SOFTWARE?

• _{When we buy a SW package, we do not really}

buy it. We just buy a license that allows us to use it, the ownership stays with the maker.

• _{Software Licenses:}

PROPRIETARY SOFTWARE LICENSE

• _{The Software that license you purchased and are not}

free.

• _{The modification and redistribution is prohibited in}

proprietary software license and consider as illegal.

• _{Most of the software in the world come under this}

license scheme.

• _Example:

TYPES OF PROPRIETARY LICENSES

• _{Single-User License}

• _{Multi-User License}

– _{For an organization, used by 5 people and can be} installed on 5 computers

• _{Concurrent-User License}

FREEWARE SOFTWARE LICENSE

• _{Also known as “Public Domain Software”.}

• _{You use it without paying anything.}

• _Examples:

Linux, LaTeX, Chrome, Opera, Netscape

OPEN-SOURCE SOFTWARE LICENSE

• _{When you purchased a SW you get it in machine}

language form (machine code), and to modify

machine code it’s a complex and difficult task.

• _{Others even give away the high-level language}

source code so that users can make changes

according to their own requirements.

• _Example:

SHAREWARE SOFTWARE LICENSE

• _{Authors say use it for free of cost.}

• _{Authors say if you are satisfied then please pay us}

some money.

• _{In some cases paying the money is optional.}

• _{Ownership belongs to author, author allow you to}

• _{These software usually you download from web.}

• _Example:

TRAILWARE

• _{Is similar to shareware but difference is that the}

SW is usable for a short period of time only.

• _{When the period is expired, it is no more is use}

until the license is not purchased.

• _{The time period may vary according to its}

developer.

• _{These kind of software can easily download from}