WHAT IS A COMPUTER…. A COMPUTER IS A DEVICE THAT ACCEPTS INFORMATION (IN THE FORM OF DIGITALIZED DATA) AND MANIPULATES IT FOR SOME RESULT BASED ON A PROGRAM OR SEQUENCE OF INSTRUCTIONS ON HOW THE DATA IS TO BE PROCESSED. COMPLEX COMPUTERS ALSO INCLUDE THE MEANS FOR STORING DATA (INCLUDING THE PROGRAM, WHICH IS ALSO A FORM OF DATA) FOR SOME NECESSARY DURATION. A PROGRAM MAY BE INVARIABLE AND BUILT INTO THE COMPUTER (AND CALLED LOGIC CIRCUITRY AS IT IS ON MICROPROCESSORS) OR DIFFERENT PROGRAMS MAY BE PROVIDED TO THE COMPUTER (LOADED INTO ITS STORAGE AND THEN STARTED BY AN ADMINISTRATOR OR USER). TODAY’S COMPUTERS HAVE BOTH KINDS OF PROGRAMMING.
3. COMPUTER CATEGORIES • Personal digital assistant (PDA): a small hand-held computer that performs simple tasks • Tablet computer: a pen-based computer that provides the screen capabilities of a PDA with the functional capabilities of a notebook
4. COMPUTER CATEGORIES • Desktop computer • Minicomputer – designed to meet the computing needs of several people simultaneously in a small to medium-size business environment • Notebook computer: a fully functional computer designed to be carried around
5. • Mainframe computer – designed to meet the computing needs of hundreds of people in a large business environment • Supercomputers – the fastest, most powerful, and most expensive type of computer
6. ANATOMY OF COMPUTER AND ITS WORKING • Hardware • Software
7. ANATOMY OF COMPUTER AND ITS WORKING • Hardware – physical aspects of computers, telecommunications, and other information technology devices • Example: Keyboard, monitor • Software -a general term for the various kinds of programs used to operate computers and related devices • Example: Microsoft Excel
8. SIX CATEGORIES OF HARDWARE • Input Device • Output device • Storage device • Central processing unit (CPU) • Telecommunications device • Connecting device
9. COMMON INPUT DEVICES Input device is a tool used to capture information and commands • Keyboard • Point-of-sale (POS) • Microphone • Mouse • Pointing stick
10. COMMON INPUT DEVICES
11. COMMON OUTPUT DEVICES Output device is equipment used to see, hear, or otherwise accept the results of information processing • Monitors Cathode-ray tubes (CRTs) Flat-panel displays Liquid crystal display (LCD) monitors Gas plasma displays
12. COMMON OUTPUT DEVICES • Printer Inkjet printers – make images by forcing ink droplets through nozzles Laser printers – form images using an electrostatic process, the same way a photocopier works Multifunction printers – scan, copy, and fax, as well as print
13. COMMON OUTPUT DEVICES
14. COMMON STORAGE DEVICES • High-capacity floppy disk • Hard disk • CD-ROM (compact disc – read-only memory) • CD-R (compact disc- recordable) • CD-RW (compact disc- rewritable) • DVD-ROM • DVD-R • DVD-RW • Flash memory device • Memory card
15. 15 RANDOM ACCESS MEMORY (RAM) • RAM – temporary storage that holds the current information, the application software currently being used, and the operating system software
16. •Memory • A large collection of circuits, each capable of storing bit • Cells (words): manageable units; typical size is 8 bits (1 byte), some machines are 16 bits (2 bytes) and some are 32 bits or 64 bits • Byte (8 bits), KB (kilobyte, 103 210 bytes), MB (Megabyte, 106 220 bytes), GB (Gigabyte, 109 230 bytes). Note: k ≠ K because 1000 ≠ 1024.
17. CENTRAL PROCESSING UNIT (CPU) • CPU – the actual hardware that interprets and executes the program instructions and coordinates how all the other hardware devices work together. • Control unit – interprets software instructions and tells the other hardware devices what to do, based on the software instructions • Arithmetic/logic unit (ALU) – performs all arithmetic operations and all logic operations • CPU Speed • Megahertz (MHz) – the number of millions of CPU cycles per second • Gigahertz (GHz) – the number of billions of CPU cycles per
18. • “brain” of a computer, consisting of • Arithmetic and logic unit (ALU): performs arithmetic calculations (addition, subtraction…) and logic decisions (>, <, =, …) • Control Unit (CU): decodes each machine instruction and sends signal to other components for carrying out the instruction. • An integrated circuit (IC) that is a full central processing unit is called a microprocessor (p); a CPU’s current instruction and data values are stored temporally inside the CPU in special high-speed memory location called registers. • CPU speed: ? MHz (M: Mega = 106, Hz=1/sec); CENTRAL PROCESSING UNIT (CPU),
19. TELECOMMUNICATION DEVICES
20. COMMUNICATION SOFTWARE • Connectivity software • enables a computer to “dial up” or connect to another computer • Web browser software • enables a computer to surf the Web • E-mail software • enables electronic communication with other people by sending and receiving e-mail
21. WIRELESS CONNECTION • Infrared also called IR or IrDA (infrared data association) – uses red light to send and receive information • Bluetooth – standard for transmitting information in the form of short range radio waves over distances of up to 30 feet and is used for purposes such as wirelessly connecting a cell phone or a PDA to a computer • WiFi (wireless fidelity) – standard for transmitting information in the form of radio waves over distances up to about 300 feet
22. CONNECTING DEVICES • Connecting devices enable the hardware to communicate with each other • A parallel connector is used to plug a printer into a system box • Parallel connector interfaces with a parallel port that is connected to an expansion card
23. BUSES, EXPANSION SLOTS, EXPANSION CARDS; PORTS, CONNECTORS • Expansion bus – moves information from the CPU and RAM to all of the other hardware devices • Expansion slot – a long skinny socket on the motherboard into which an expansion card is inserted • Expansion card – a circuit board that is inserted into an expansion slot • Ports – simply the plug-ins found on the outside of the system box into which a connector is plugged into • Popular connectors include: • USB (universal serial bus) • Serial connector • Parallel connector
24. INTRODUCTION TO COMPUTER SOFTWARE
25. TYPES OF SOFTWARE • System Software • Application Software
26. SYSTEM SOFTWARE • System Software includes the Operating System and all the utilities that enable the computer to function. • System software is a term referring to any computer software which manages and controls the hardware so that application software can perform a task. • Example • Operating Systems, Compiler, Loader, Linker, Interpreter.
27. APPLICATION SOFTWARE: • Application Software includes programs that do real work for user. • Example: • Payroll systems, Inventory Control, Manage student database, Word Processor, Spreadsheet and Database Management System etc.,
28. OPEN SOURCE SOFTWARE: • Open source software (OSS) is computer software whose source code is available under a license that permits users to use, change, and improve the software, and to redistribute it in modified or unmodified form. • It is often developed in a public, collaborative manner. • Well-known OSS products are Linux, Netscape, Apache, etc.,
29. SYSTEM SOFTWARE Operating System: • Operating System is a software, which makes a computer to actually work. • It is the software the enables all the programs we use. • The OS organizes and controls the hardware. • OS acts as an interface between the application programs and the machine hardware. • Examples: Windows, Linux, Unix and Mac OS, etc.,
30. PROPRIETARY SOFTWARE • Proprietary software (also called non-free software) is software with restrictions on using, copying and modifying as enforced by the proprietor. Restrictions on use, modification and copying is achieved by either legal or technical means and sometimes both. • Proponents of proprietary software are Microsoft. • Ex: CAD, Nortan Antivirus etc.,
31. SYSTEM SOFTWARE (CONT.): • Compiler: A compiler is a program that reads a program in one language – the source language and translates into an equivalent program in another language – the target language. Source Languages Target Languages ‘C’ language ‘C’ language ‘Pascal’ language Machine language FORTRAN language C++ language ADA language
32. SYSTEM SOFTWARE (CONT.): • Loader: A loader is the part of an operating system that is responsible for loading programs into memory, preparing them for execution and then executing them. • The loader is usually a part of the operating system’s kernel and usually is loaded at system boot time and stays in memory until the system is rebooted, shut down, or powered off. • In Unix, the loader is the handler for the system call execve().
33. SYSTEM SOFTWARE (CONT.): • Linker: A linker or link editor is a program that takes one or more objects generated by compilers and assembles them into a single executable program. • Linkers can take objects from a collection called a library. The objects are program modules containing machine code and information for the linker. • The linker takes care of arranging the objects in a program’s address space.
34. SYSTEM SOFTWARE (CONT.): • Interpreter: An interpreter is a computer program that translates and executes instructions written in a computer programming language line-by-line, unit by unit etc., • An interpreter needs to be able to analyze, or parse, instructions written in the source language. • Example: Lisp systems, etc.,
35. APPLICATION SOFTWARE: Word Processors: Word processing is a tool that helps user in creating, editing, and printing documents. Word processors will normally have the following capabilities built into them: • Spell checking • Standard layouts for normal documents • Have some characters appear in bold print, italics, or underlined • Center lines, make text line up on the left side of the paper, or the right side of the paper • Save the document so it can be used again • print the document. Examples: WordPerfect and Microsoft Word
36. APPLICATION SOFTWARE (CONT.…): Spreadsheets: The spreadsheet packages are designed to use numbers and formulas to do calculations with ease. Examples of spreadsheets include: • Budgets • Payrolls • Grade Calculations • Address Lists The most commonly used spreadsheet programs are Microsoft Excel and Lotus 123.
37. APPLICATION SOFTWARE (CONT.…): Graphic Presentations: The presentation programs can make giving presentations and using overheads easier. Other uses include: • Slide Shows • Repeating Computer Presentations on a computer monitor • Using Sound and animation in slide shows The most recognized graphic presentation programs are Microsoft PowerPoint and Harvard Graphics.
38. APPLICATION SOFTWARE (CONT.…): Database Management System (DBMS): • A DBMS is a software tool that allows multiple users to store, access, and process data into useful information. • Database programs are designed for these types of applications: • Membership lists • Student lists • Grade reports • Instructor schedules All of these have to be maintained so you can find what you need quickly and accurately. • Example: Microsoft Access, dBASE, Oracle.