Software What is software? Software is a general name given to all programs that can run on computer hardware such as spreadsheet. There are two types of software, namely operating system and application software.

Operating System Is a program that controls the hardware directly such as windows XP, and UNIX OS, Linux os, Mac OS,...etc OS performs the following tasks:  Manage the system security  Manage the system resources  Manage the transfer of data to and from various peripherals  Provide interface between the applications and the hardware

OS acts like a shell around the hardware Operating System hardware application user

Multitasking It is the ability to run more than two programs simultaneously. Example chat with your friend using Skype and downloading latest Oscar awarded movie, while preparing the question for MBBS III sem students ( using more than three programs )‏

Multiuser Allows several users to access the same data simultaneously. Web server, mail, chat rooms, news groups torrents.

User Interfaces Consists of cursors, prompt, icons, menus which allow you to get something done using your computer. It allows you to communicate with the computer. User interface may be:  Command-driven  Menu-driven  Graphical User Interface (GUI)‏  Voice recognition.

Command Driven Interface You type the instructions which is usually abbreviations, in order to get something done. Examples window button → run → calc Winword, notepad, writer,... etc Cmd alt+enter, dir, cd, copy, ping, ipconfig,....

Menu Driven Interface Produces a list of options available within a program and the user make a selection by using either a mouse or keyboard. Example bank ATM.

Graphical User Interface A GUI provide an Interface to the user allowin him to communicate with the computer through pictures (Icons) and pull-down menus. It uses WIMP (Windows, Icons, Menus, Pointing devices) to implement. Example Windows XP is a GUI which allows users to use pictures and pull-down menus.

Voice Recognition A user can talk to a computer which understand and replies back to the user or asks questions or clarify the statements which are not clear such as Doctor Expert Systems which is being used by many doctors for their patients. A doctor dictates a medical report in the following picture.

Designing a User Interface In ordr to design a user-friendly GUI take into account the following: Consistency: each part of the software behave in the same way as another. Positioning of the items on the screen: icons and menus should be consistent. Use of colors: should be chosen carefully. Use of sound: provide the option to turn on or off the sound. Availability of help: provide online help.

Utility Programs Utility programs are often provided as part of the operating system. A utility program is a program that performs a task which is often needed such as list files. Tasks carried out by utility programs include  Rename files  Copy files  List files  Deleting files  Sorting files  Printing files Other utility programs can ge bought such as Norton antivirus.

Applications Software Used to perform specific tasks  Word Applications packages include:  Word processing such as MS word  Spreadsheets software such as MS excel  Database software such as MS access  Presentation software such as power point

General Purpose software Off-the-shelf software is readily available in the market which is general purpose. Example word processor is a generic software and available in the store. It is cheap but cannot be modified.

Programming Languages A program is a set of instructions that the computer can understand. Since the computer understand the binary code the program must be translated to binary code for the computers to understand. There are two types of programming languages, namely, low-level languages and high-level languages

Low-level Languages Low-level languages are languages that are easy for the computer to understand but are more difficult for the programmer to understand. Example assembly language Assembly language uses simple instructions such as ADD SUB and LDA

High-level Languages A high-level-languages is developed with the programmer in mind rather than the computer. It is easy for the programmer to understand. High-level language instructions are similar to English. High-level language programs can be used on any hardware Some high-level-languages like BASIC, FORTRAN, COBOL, JAVA, HTML, VB, C++,...etc

Translation Programs Used to convert the program command into machine code There are three types of translation programs:  Compilers  Interpreters  Assemblers Compilers change high-level languages instructions into machine code. They change entire program one time.

Interpreter change high-level languages instructions into machine code line by line. Assembler: change the assembly language code into machine code. it translate the whole program.