Chapter 4 Software

Introduction Program: is a set of sequence instructions that tell the computer what to do. Software: is a collection of programs, data and information, which is built on planning, knowledge and thinking. Programmer: is the person who makes the program using one of the computer languages.

Kinds of Software There are two kinds of software: 1. System software 2.Application software

System Software 1.System software: it’s the software which is used by the computer or operates a computer system such as: operating systems, programming languages, and translators. 1.Programming languages: A set of words, rules, syntax and semantic used by a programmer to input his instructions to the computer to execute a task. There are many programming languages such as: Fortran, Pascal, C++, Java …etc.

Generations of Programming Languages  Machine Language: it’s written in 1,0 digits (binary system), and it’s difficult language to understand and analyze and it doesn’t need a translator.  Assembly Language: it depends on using some short (mnemonic) symbols like MUL for Multiply and SUB for subtract, it uses addressing symbols like which are variable names used to store data inside them for example the variable TOTAL can be used instead of the number , which make it easier to the programmer to understand, it uses an Assembler to translate the program instructions into Machine Language.

 Third Generation Languages or Higher Level Languages: use statements that one can understand, those languages can be used to solve large problems in programming and they need translators (compilers) such as C++ and JAVA.  Application Generators: also called fourth generation languages and they are used to create files, forms, reports …etc to meet the users requirements, they are much simpler than third generation languages, those languages tell the computer what they need to do not how to do it an example could be suppose we want to retrieve all the students who passed from the students table, we could write the following SQL statement to do the job: SELECT st_name, st_mark from students WHERE st_avg >=50.

 Object Oriented Languages: These languages depend on objects, where every object has it’s own variables or data and it’s own methods or operations. These objects interact between each other by exchanging messages, Encapsulation is very important characteristic that distinguish object oriented programming from any other kind of programming languages, which collects a number of operations and variables in one place and they are accessible only by special instructions.

2.Compilers and Interpreters Programs usually written in C or Assembly languages, translates the source code, which is written in any programming language to object code, which is the machine language (0,1), this process is done once while the interpreter translates and executes every statement one by one. 3.Operating System It’s the most important system software, as it holds all programs that operates the computer such as: starting the computer, displaying on the monitor and using the keyboard and accessing all the equipments and other software programs, Windows, Unix, Linux are some of the most popular Operating systems.

Functions of the Operating System  Booting Up  User Interface: to run other systems software  Task and resources management: to manage the memory, the input, processing and output processes when executing systems software.  Monitoring  Files management: manage the files and folders which store the data and information needed by systems software.  System security: protect the information from being accessed illegally.

Types of Operating Systems  Multitasking OS( متعدد المهام ): such as Windows  Multiprocessing OS( المعالجة المتعددة ): Such as Unix multi CPU  Timesharing OS( تقسيم الوقت على المستخدمين ): multi-users sharing the same CPU.  Network OS: such as Windows NT  Real Time OS: such as medical devices, where the input, processing and output occurs in the same instant( مباشر ).

2.Applications Software  Software which are commonly used by users, such as: word processors, spreadsheets, programs, graphics and drawing programs, presentation tools, publishing tools …etc

Interface The way that the software communicates with the users. Types of Interface:  Command Line Interface: it’s a non-user friendly interface, where users have to have a good knowledge in dealing with the computer.  Graphical User Interface (GUI): it’s a user friendly interface, which usually contains Icons, pictures, menus and windows… to make the communication between the users and the software easier to use and more usable.

System Development Involves the design, implementation of computer operations to replace or update business processes within an organization. Steps of System Development  Define requirements: understand the business problems by interacting with users of an organization.  Asses Feasibility( الجدوى ) : discuss and determine the cost/benefit of developing a system with the organization's management.  System Analysis: analyze the information system needs, by interviewing the users, and the organizational management to improve the current system or replace it with a new system.  Product Development: Involves the upgrade and/or development of the organization's hardware, software, people, data resources and the information products that will satisfy the functional requirements of the proposed system.  Testing: test the system  Training: train users to use the new system  Hand over to the client  Monitoring and Maintaining the system

Multimedia Multimedia is the use of different media in computer programs such as: text, graphics, audio, video and animation. Multimedia files used in, presentations, education, learning, games and commercial products. Multimedia Computer Specifications: a)Process Speed: 500 MHZ, RAM capacity: 64 MB, Hard Disk Capacity: 6 GB and other equipment. b)Peripherals: CD drive, sound card, microphone, loud speakers and modem. c)A large monitor with a SVGA screen card. d)DVD drives to display movies. Multimedia Programs: you can use the multimedia programs in many ways, Interactive & Intelligent Software