Introduction to Software.pdf

Introduction to software  Consists of a series of instructions What is that tells the computer what to do software? Also called a program Two Major System Software Categories of Computer Software: Application Software Application Software Application software co...

Introduction to software  Consists of a series of instructions What is that tells the computer what to do software? Also called a program Two Major System Software Categories of Computer Software: Application Software Application Software Application software consists of programs designed to make users more productive and/or assist with personal tasks To make business To assist with activities more graphics and efficient multimedia projects To support home, To facilitate personal, and communications educational tasks 4 Application software Word processing software allows users to create and manipulate documents 5 Word processing Word processing features include: Grammar AutoCorrect AutoFormat Collaboration Columns Checker Reading Ink Input Macros Mail Merge Research Layout Search and Smart Tags Tables Templates Thesaurus Replace Tracking Voice Web Page Changes Recognition Development 6 Spreadsheet software Spreadsheet software allows users to organize data in rows and columns and perform calculations Create charts 7 Spreadsheet A function is a predefined formula that performs common calculations FV NPV PMT PV RATE DATE NOW TIME ABS INT LN LOG ROUND SQRT SUM AVERAGE COUNT MAX MIN STDEV IF 8 Presentation software Presentation software allows users to create visual aids for presentations to communicate ideas, messages, and other information to a group 9 System software System software serves as the interface between the user, the application software, and the computer’s hardware. Two types of system software are: Operating System Utility programs 10 What is system software? Programs that control or maintain the operations of the computer and its devices Operating System (OS) is a set of programs that coordinates all activities among computer hardware Utility Programs allow the user to devices and allows perform maintenance-type tasks users to run usually related to managing a application software computer, its devices or its programs Types of OS MS DOS Windows 3.X, Windows 95 Windows 7 Windows 8 Windows 98, Windows ME Windows 10 (Millennium Edition) Windows 11 Windows 2000 Android Windows XP Apple operating systems Windows NT (MAC OS X) Linux and Unix iOS Windows VISTA Windows: Apple Macintosh (Mac-OS) MS - DOS Linux Operating System  The process of starting or restarting a computer is called ‘BOOTING’. When turning on a computer that has been powered off Booting completely, you are performing a COLD BOOT(simply pressing the computer's power Process button once to turn it off and then again to turn it back on). A WARM BOOT is the process of using the operating system to restart a computer. Types of OS  Multi-user: Allows two or more users to run programs at the same time. Some operating systems permit hundreds or even thousands of concurrent users. Multiprocessing: Supports running a program on more than one CPU. CLASSIFICATION Multitasking: Allows more than one program to OF OS run concurrently Multiprogramming: Allows different parts of a single program to run concurrently Real time: Responds to input instantly. General- purpose operating systems, such as DOS and UNIX, are not real-time. Types/Modes of processing Batch Processing – when data collected is grouped together & processed at a certain time such as weekly, monthly (used by JPS, NWC) Types/Modes of processing Online processing – data is collected & processed immediately, user interacts directly with computer at anytime through the IO devices (ATM, online games, flight systems) Types/Modes of Processing  Real-time processing – is the method of inputting, processing & outputting data continuously (without delay). Eg. of RTP systems (anti-missile systems, aeroplane landing control system, flight simulation system, electronic fund transfer system, ticket reservation systems) Types/Modes of Processing  Interactive processing - simplest way to work on a system. You log in, run commands which execute immediately, and log off when you've finished. You can use either the command line or a graphical environment Types/Modes of Processing  Time sharing processing – method of processing that allows many users to use a computer system simultaneously eg. more than one users can request a file at the same time  For each of the following tasks, suggest an appropriate processing mode: controlling a robotic arm Guess monthly stock taking processing what, its checking criminal records your turn! ATM transactions reserving a movie Components (parts) of OS Kernel Scheduler Process Manager File Manager Parts of OS (Kernel) Kernel is a program that makes up the main part of the OS. The kernel is the first part of the operating system to load into main memory (RAM) during booting (i.e., system startup after the bootloader), and it remains there for the entire duration of the computer session because its services are required continuously. Kernel executes processes and handles interruptions. Parts of OS (Scheduler) The part of the operating system that initiates and terminates jobs (programs) in the computer. Also called a "dispatcher," it maintains a list of jobs to be run and allocates computer resources as required Schedulers keep all computer resources busy by allowing multiple users to share system resources effectively Parts of OS (Process Manager) Process Manager – enables processes by allowing OS to allocate resources to share and exchange information, protect the resources of each process from other processes and enable synchronization among processes Parts of the OS Shell – this is a program that acts as an interface between the user & the OS, it allows the user to enter commands for the OS to execute Parts of the OS FAT- this refers to the way Windows stores data on the hard drive. "FAT" stands for "File Allocation Table," which keeps track of all your files and helps the computer locate them on the disk. FAT 32 is an improvement to the original FAT system, since it uses more bits to identify each cluster on the disk. Parts of the OS Translator - computers understand only binary language. Translator is a software used to convert programs into binary/machine language. Three types are interpreter, compiler & assembler. General Purpose OS & Dedicated OS The basic difference of using a GPOS or a DOS lies in the nature of the system i.e whether the system is “time critical” or not! A system can be of a single purpose (DOS) or multiple purpose (GPOS) GPOS (Multipurpose) Personal computer (PC) is not a time critical system Multipurpose system (run many applications at the same time) A GPOS is used for systems/applications that are not time critical eg. Windows, Linux, Unix GPOS(Multipurpose) After pressing the SAVE button of a finished document, there is no particular time limit that the doc should be saved within 5 seconds. It may take several minutes (in some cases) depending upon the number of tasks and processes running in parallel Dedicated OS Dedicated OS designed to be used in specific systems designed to operate on small machines like phones they operate with a limited number of resources they are very compact and extremely efficient by design. Dedicated OS cont’d ensures a higher level of security banks use dedicated operating system to prevent cyber attacks on financial transactions Dedicated OS is custom made to do a specific function at maximum efficiency Dedicated OS Automated Teller Machines (ATM) time critical system ATM card user gets his money from machine within 4/5 seconds after confirmation (user will not wait 5 minutes at the ATM after he pressed the confirm button, so ATM is a time critical system) Types of Dedicated OS iOS 8 is the eighth major release of the iOS mobile operating system developed by Apple Inc. Types of Dedicated OS Mac OS is the computer OS for Apple Computer's Macintosh line of computers (latest version, Mac OS X a desktop interface with some 3-D appearance characteristics) Functions of the OS Starting a Computer Providing a User Interface Managing computer resources Managing files and memory Maintaining Security Managing Tasks Multiprocessing Functions of OS Process Management Main Memory Management File Management I/O System Management Secondary Management Utility/Protection System Other Functions of OS based on type of OS it can also: Process Management Process management – allocates time for processes to use the CPU, keeps a check on other processes that are waiting to use the CPU, or signals when CPU is available Main Memory Management When program or data too large to fit into main memory, a method called virtual memory can be used to split the program into manageable blocks. The required blocks are split between main memory & secondary storage, giving the impression that the computer has expanded its memory to accommodate the data File Management Files need to be saved, copied, renamed & deleted. A file manager checks the amount of memory needed to perform these tasks, & manages the organisation of the files in secondary storage. I/OS System Management Since each device has a program called a driver that allows the device to communicate with the computer, the flow of information among devices must be managed & coordinated. The use of buffers is one way to manage these devices. Secondary Management Since main memory (primary storage) is volatile and too small to accommodate all data and programs permanently, the computer system must provide secondary storage to back up main memory. The operating system is responsible for the following activities in connection with disk management: – free space management, storage allocation, disk scheduling Utility Software This is a specialized software that supports the OS in housekeeping tasks to increase the efficiency of the computer system Protect & maintain the system software examples include protect software against damage cause by viruses, making copies of files (back up) software Examples of Utility Software Utility Software User Interface The OS support the user interface of the computer. A user interface is the way in which a user interacts with a computer system. It may be software interface (command driven interface, menu driven interface & graphical user interface GUI) or hardware interface (touch screen, special keyboards, sensors). Command Driven/Line Interface require user to type in commands using special language difficult for new computer users to understand Microsoft Disk Operating System (MS-DOS) Menu Driven Interface developed because some people found it difficult to understand command driven Gives users a list of command options called a menu (easy to understand) Options are chosen using keyboard or mouse Graphical User Interface (GUI) Provide users with Windows, Icons, Menus, Pointers (WIMP) GUI provides users with toolbars, drag & drop, labels, on screen assistants, buttons) Main interfacing device is mouse