Partial preview of the text
Download Course: Programming Fundamentals ( Introduction to Computers) and more Lecture notes Mathematics in PDF only on Docsity!
HAPTER -0 ONTRDDUCTON TO COMPUTERS) ‘++ Memory of a Computer: ‘Storing Data program or result is the main function of memory unt. This unit stores given commands and data. ‘Memory is divided into two parts. They are (2) Primary Memory or Main Memory and _(b) Secondary Memory or Auxlary Memory. (a) Primary Memory or Main Memory: In which memory, processor can communicate directly is called primary memory. This memory stores data or information temporally. After processing data are stored Into secondary memory. There ae differen types of primary memory Such as — (ROM (Read Only Memory) (ll) RAM (Random Access Memory) _{Il) Cache Memory. () ROM: Read only memory is shorty called ROM. The data stored in a ROM chip can only be read and sed, they cannat be changed. Tiss why it called read only memory. At the time of making ROM chip by the manufacturing company which data are stored, cannot be deleted, stored permanently. But now a days data of some ROM chips can be changed or altered in some special ways. Types of ROM chips ate described below — (a) MOM (Mask ROM): n which manufacture company, made ROM-Chip they that company also write program own and delivered in the market. Later this program can never be changed, (b) PROM (Programmable Read Only Memory): In this case one manufacturing company makes only Rom chip and another company writes program. This chip is also unchangeable. {(c) EPROM (Erasable Programmable Read Only Memory): EPROM has a glass window, which covered with 3 label. Program can be changed by high-intensity ultra volt ray with te help of this glass window. Bright sunlight can erase EPROM. But no problem Is aised in roomlight. (a) EEPROM (Electrically Erasable Programmable Read Only Memory): EEPROM is more accessable than EPROM. ‘This ROM can be changed or updated bit by bit through electricity, software or utility. At present EEPROM is used in PCs BIOS, whichis introduced as Flash BIS. (i) RAM: RAM is an important component of 3 computer. Acronym of RAM is Random Access Memory, which stores data program temporally while computer is started on. This is why it is called temporary ‘memory. While PCs started on, which works have been done by user, are stored by RAM. In any time from any place of it, we can read or write data, this is why it is called Random Access Memory. itis temporary this memory is also because when electricity is gone, all the data of it is deleted. So this ‘memory called volatile or power dependent memory. In designing or desktop publishing works or playing {games minimum 1GB RAM is needed, At present market diferent branded RAM of RAM of different capacity are available such as 168, 268, 4GB ete. ‘Mainly RAM has two Categories ~ (a) BRAM. and_(b) RAM (a) DRAM (Dynamic RAM): Tis type of RAM stores charges into mini capacitor and saves data refreshing through external circuit (b) SRAM (Static RAM): Static RAM can keep data in keeping with power supply. I's speed Is comparatively higher and its more expensive to make because flip-flop circuit makes it, which is expensive. Generally this RAM isfor cache memory. CHAPTER OF ONTIODUCTINN compa Besides this there are some types of RAM such as —~ (€) EDO RAM: When freely data writings finished, this RAM can send data quickly. Having higher frequency EDO RAM is speeder than ORAM. This type of RAM is generally used for Pentium machine. (4) SDRAM: This RAM is fit for Pentiumll and Pentiunl class computers. is operating speed is 100 and 133 Miz) () SGRAM: This RAM Is suitable for using graphics card. At the time of working by taking information in video frame buffer, this RAM can swiftly read and write data for graphies processors. (VRAM: This type of RAM Is good for video card. is every memory cells of dual por. (g) RORAM: RORAM | the fitest fr high speed system lie coppermine of Intel and Athlon of AMD. I's speed is 1800 MHz and data transfer rate is 1.6 6.8/Sec (h) CMOS RAM: CMOS RAMs a special type of RAM, which stored the configuration information of BIOS. CMOS RAM needs low power. When computer is remaining off, a mini rechargeable battery uses to supply power to (CMOS RAM. (ii) Cache Memory :n which cache memory placed between the main memory and the microprocessor iscalled the external cache, The cache which buil-in with the processor is called the internal cache, Cache memory is ten times speedy than main memory. It saves the access time and increase the speed ‘and real performance of processor. ache memory is very expensive to manufacture, CS a EE ee which memory processor cannot communicate directly is {b) Secondary Memory or Auxiliary Memory: called secondary memory. In this memory data are stored permanently, As secondary memory Floppy disk, Hard disk, compact disk, Magnetic tape etc. are used. * Virtual memory: Recently operating systems can use auxllary memory, like the ree space of hard disk is the part of main memory. Mac OS and Windows have this facility, This system is called vitual memory. Mind that the space, which Is the portion of main memory of any hard dis, that means which is used as vtual memory, that space will be short to store data if virtual memory i on. But when the vitual memory willbe off, which space of hard disk was sanctioned will be free to store data. Virtual memory are specified by the user. + Hardware: Computer hardware isthe physical pat ofa computer. Itincludes all the mechanical, electronic and ‘magnetic components, such as monitor, printer, electronic circuits, floppy, hard disk etc. For instance, the RAM is apiece of hardware, Most computer hardware is nat seen by normal users. It isin embedded systems in various devices. ** Software: The software is a collection of instructions written in a computer language that can be understood by the processing unit or the computer tobe able to give a desired output. It includes operating systems, utlity programs, aplication programs, programs in various computer languages etc. The development of 2 user program i also a piece of software. There are two major categories of software ~ (a) System software and _(b) Application software. 5. asin Jahan oe za = tt ae Z {o)Text based operating systems : Operating systems, which are operated by text-based commands, is called text- based operating system. DOS and UNIX ae text based operating systems. 05/2 Isa text based operating system but it can be used with the help of GUl operating system with GUI software. ~ Disk operating system (00S) : MS-DOS stands for Microsoft Disk Operating System. tsa single user ‘operating system for IBM and IBM compatible personal computers. It was introduced in 1981 joining by Microsoft ‘and JBM and was the most popular operating system for personal computers in 1990s. Its popularity started reducing in the 1990 withthe launch (open) of Microsoft windows operating system. The IBM version of MS-DOS is known as PC-DOS, DOS is helpful to organize dsks and use them effcienty. It helps to create and manage files ‘on disks, make copies of them or remove unwanted files from the disks. (b) Graphical user interface (GUI) operating systems : Mac OS, Windows 3x. Windows 95, Windows 98. Windows 2000 professional. Windows XP, Windows NT, Windows Vista, LINUX are graphical user interface operating systems. Most of the operational procedures are common in these operating systems. People also refer to it asa point and click interface because we use a mouse to point at on screen objects and then “cick” them. Apple ‘computer Introduced the first successful GUI with its Macintosh computer in 1984, Y Microsoft Windows Operating System : Microsoft windows operating system was developed by Microsoft Corporation to over come the limitation of its own MS-DOS operating system. The first successful version of this operating system was Windows 3.0, which was released in 1990. The subsequently released versions were Windows 95, Windows 98, Windows 2000 professional, Windows XP and Windows Vista. The ‘numbers associated with ths released version indicate their year of release. (© Main features of Windows operoting systems are: 1 ts native interface is a Graphical User interface (GU!) 2. Microsoft Windows was designed to be not just an operating system but also a complete operating ‘environment. 3. [tsa multi-user and mult-tasking operating system, That i, a user may run more than one programs ata time, (© Necessity of operating system : Operating system has made the use of computer easier, GUI makes ‘operating system very easier to the general people. Asa resuit use of computer becomes easier Operating system ‘also makes the bridge between hardware and software for smooth and proper functioning of computer. No ‘computer system can run without operating system, The internal task of computers are conducted or performed by the operating. system. Operating system plays the role of manager for performing works of computers propery and effectively. So. operating system isthe most and indispensable diving force f computer. ‘Y Windows 98 : Microsoft Windows 98 was released in June 1998. it was the upgrade to Microsoft ‘Windows 95. While tis was not as big as release as Windows 95, Windows 98 has significant upgrades, fixes and ‘supports for new peripherals. Some ofits new features ae protection, improved support for new devices. Internet ‘explorer 4.0, Customizable taskbar, Active desktop etc. Windows 98 SE includes the same additional features 2s. Windows 98; however, includes additional fxes and ll of year 2000 patches have been included in Windows 98 ‘SE. The various new features of Windows 98 SE are — ‘Software updates: Updated versions of internet Explorer, Outlook Express, Windows MediaPlayer, Direct X Net Meeting and more. Drivers Support: Additional support for latest technology such as MM, USB, Intel, Pentium! and more, SNAG NAre SE CHAPTER AENTIODUSTN COMPUTES rf : Windows XP isa proprietary operating system developed by Microsot for use on general ‘purpose computer systems, including home and business desktops notebook computers, and media centers. The letters "XP" stands for experience, Windows XP was frst released on October 25, 2001, The two major editions of ‘the operating system are Windows XP Home Edition, designed for home users, and Windows XP professional, ‘signed for business and powerusers. Windows XP is known for Its Improved stability and efficiency over [revious versions of Microsoft Windows, Windows XP introduced several new features 4. Faster startup and turnoff sequences. 2. The ability to discard a newer device driver in favour ofthe previous one 3. Interface s more user friendly, 4. Fast user switching, '5. The clear type font rendering mechanism. 6, Remote Desktop functionality ete * UNIX: Unix or UNIX is a mult-user operating system that was developed by some of the members of the Multics (Multiplexed Information and Computing Service) team at the bel! abs starting Inthe late 1960s. t ‘was first written in the assembly language, Later in 1973, t was rewritten in C language, Today, Unix isnot just the ‘work of a couple of programmers, many other organizations, institutes, and various other individuals have Contributed significant additions to Unix and its variants. Unix operating systems are widely used in both servers ‘and workstations. The most popular varieties of Unix are Sum Solaris, GNU/Linux, and Mac OS X ** Internet: In the recent word internet isthe monopoly media in computer networking. From last few years this name s merely introduced to us, But most of us have no clea idea about internet, Really Internet i kind of Jnter-communication through innumerable computers ofthe whole world This broad computer network is called network of network or internet work, abbreviatly Internet. Lately its more abbriviated form is “net”. All the computers of network are connected with with a server. Computers of Internet users are connected through telephone lines withthe servers of Internet services providers: Again these servers are connected ‘withthe server of international internet service provider through satelite Internet is divided into two types Such as~= 4, Dialupinternet._ and 2. Broad Band Internet. ** VOIP (Voice Over Internet Protocol}: VOIP uses your dial-up or broadband connection to make free calls ‘or cost much less than a normal telephone call ver the internet. The acronyms VOIP stands for Voie over Internet Protocol and isthe technology for transmitting voice conversations via the internet. The Internet Protocol (IP) was originally designed for data networking. The success of IP in becoming a world standard for data networking has led to Its adoption to voice networking, VOIP has become popular largely because of the ‘cost advantages to consumers over traditional telephone networks. Most VOIP providers offer unlimited national calling but the direction in VOIP is clearly toward global coverage with unlimited minutes for alow. ‘monthly fee. E-Mail Electronics Mail's shortly called E-Mail tis one type of Improved and mail post; it's an international electronic media and broad system. In this ‘communications of ‘mainframe, mini PC's are committed. Which messages are prepared and sent through computer by sender and atthe same time those are received by payees through their computers are called E-Mail or Electronics Mall Payees or senders can print the messages sent from computer to computer if they need. Most of the ‘opportunites of internet can be enjoyed through E-Mail In this result time is saved. expenses are lower and after all data are able to be read. Usage of €-Mail inthe world i o spreading that Its erying need for a modern ‘man to have an E-Mail address Recently our postal department has started E-Mall service through big towns. nitt anne! wAPTER oF aINTRAPWOTDN TCOMPHTERN (Local Area Network (LAN): A network that located relatively in small area such as 8 room, a single bulding, ship, a hotel, a hospital a college / university campus or an alert, Local are networks are sometimes called {single location network {W) Metropolitan Area Network (MAN) A network that connects two oF more loca area networks together but ‘does not extend beyond the boundaries ofthe immediate town, ety or metropolitan area, {ll) Wide Area Network (WAN) :A network that covers a relatively broad geogr {transmission faclities provided by common carriers, such as telephone compani ‘ofa WAN is the Internet, which isthe largest network inthe world. hie area and that often ** Web Page : The information stored in computes isnot ony text but ao graphic (nes), sound and vdeo This Is called multimedia Information. A computer connected to Internet ean store multimedia Information Indexed using hypertext markup language (HTML) This called webpage very web pag ha 8 nique address Called Universal Resource Locator (UR) ++ Website: A computer located at an Internet address can store many we pdge, Such a computer is called» web site. *+* world Wide Web : The collections of all web sites inked together by hypertext links s known as the world wide web (www). +* Computer Virus: A computer virus Isa set-replicating code (program) that can copy itself and infect ‘computer without permission or knowledge of the user. All computer viruses are manmade. Viruses can be transmitted as attachments to an e-mallnote or ina downloaded fle, or be present on a diskette, CO or US8 drive ‘They atach to boot sectors, partition table, operating system files, device drivers and application executable files “The computer viru gets its name from the biological virus. The word itself comes from Latin word meaning slimy liquid or poison. It acronym is ial Information Resources Under Si ¥ Symptoms of the virus: 1. Slow response ofthe computer. 2, Deletion of executable files when they are run, 3, Reduction in avaliable memory. . Odd messages are displayed on the screen. 5, Unnecessary dsk accesses et *** Digital device: device that performs their tasks by using digital signals called digital device, Digital device Is shorty called Digivice. PC, CO player, digital watches etc are the examples of egal devices, ** Analog device: Analog device Is an apparatus that measures continuous information. The measured analog signal hasan Infinite numberof possible values. The onl limitation on resolutions the accuracy ofthe measuring device, Such apparatus operates with variables, which are constituted by continuously measured quantities. These {quantities can be voltage, resistance, rotation and pressure. Fax machine, Television, Steam engine, Mercury thermometer, Bathroom scale. Speedometer of a car, analog watches etc are the examples of analog devices SN esip Taha WAPTER-¥ ONTRODUCTIN Ty ** Hard disk: & hard disk (Sometimes abbreviated as HDD) Isa fixed disk inside a computer that stores and provides relatively quick access to large amounts of data on an electro-magneticlly charged surface set of Surfaces. Tody's computers typically come with a hard disk that contains several billon bytes (gigabytes) of storage. IBM introduced itn 1956; HDD became the dominant secondary storage device for general-purpose ‘computers bythe early 1960s, Continuously improved, HDD have maintained this postion ito the modern era of servers and PCS. More than 200 companies have produced HOD units, though Seagate, Toshiba and Western Digital manufacture most current units. An HDD consists of one or more rig ("Hard") rapialy rotating discs (platters) with magnetic heads arranged on a moving actuator arm to read and write data tothe surfaces. It is ‘Usually partitioned asa single data partition, but can be sub-divided ito several partons. ‘** Motherboard: Mother board also called the "System board’, "main board" "base board” or "logic board”, it isthe primary printed circult board in a computer or other electronic device. In both the AT and ATX designs, the ‘computer components included in the matherboard ae: © The microprocessor © (Optionally) coprocessors @ Memory © Basic input/output system (810s) © Expansion slot interconnecting circuitry ‘Additional components can be added toa motherboard through is expansion sot. Laptop motherboards have no ‘expansion slots for more peripherals. ** Key punch : A key-punch isa device for precisely punching hoes into punch cards 3t specifi locations 35 determined by the keys struck by the operator. ‘Amathematical circuit that performs high-speed floating point operations. It is generally built into the CPU chip, however in older PCs, such asthe 386 and 4865x, the math coprocessor was an optional, separate chip, Floating point capablity Is very important to computation-ntensive CAD work, and many CAD programs will not operate without it. A spreadsheet may use it if avaliable, butt is not mandatory. ** VSAT: VsAT (Very Small Aperture Terminal) isa satelite communications system that serves home and business users. A VSAT end user needs a box that interfaces between the users computer and an outside antenna with 2 transceiver. The transceiver receves or sends a signal toa satelite transponder in the sy. The satelite sends and receives signals from an earth station computer that acts asa hub fr the system. Each end users interconnected ‘with the hub station via the satelite in a star topology. For one end user to communicate with another, each transmission has to first goto the hub station, which retransmit it va the satelite tothe other end user's VSAT, \VSAT handles data, voice, and video signals. Live satellite communication was developed in the sixties by NASA, named Syncom1-3. It transmitted live coverage of the 1964 Olympics in Japan to viewers in the US and Europe. Soon after, on April 6, 1965 the first commercial satellite was launched into space, Intelsat 1, nicknamed Early Bird ‘+ Satellite: & satelite is a machine that goes around, or orbits a planet or star. For example, Earth ga satelite because it orbits the Sun. Likewise, the moon isa satelite because it orbits the Earth. Usually, the word “satelite” refers toa machine thats launched into space and moves around the Earth or another body in space, Earth and ‘moon are the examples of natural satelits, Thousands of artifial or man-made satellites orbitthe Earth. Sputnik- 41.was the first satelite in space. The Soviet Union (now Russi) launched it in 1957. With satellites, TV signals and phone calls are sending upward toa satelite Then, almost instantly, the satelite can send them back down to different locations on earth. ** optical Fibre: An optical fle sa thi, feible and transparent re made of lass strand that cases light along ts length tis as thinners human hair and information and data at transmitted trough this inthe form of ight signals. Optical fibres are widely used in Rbre-opic communications, which permits transmission over longer distances and at higher bandwidths than other forms of communiaion. Fibres are used instead of metal wires because signals rave! along them with es ss 33 Fare thon HAPTER 0 ANTRODUCTION TMP © Disadvantages (High-Level Language) : (1) To perform works inthis language isnot so fast as low-level language. {2) A translator Is needed for machine to understand ths language. These translators are compiler and Interpreter. ‘Thore are high-level languages more than twenty in numbers. Main ofthese are (1) Basic (2) FORTRAN (3) PASCAL (a)coa0t (5) cv (6) 46+ (ava) (7)oRACAL (a)aLcoL ete ** Mid Level Language: The programming languages which available the advantage of low-level languages and high-level languages are called mid-level language. in mid level languages the bt lebel program control the hardware and we can write a sytem program. it also gives the advantage of high-level languages atthe same time. There are many mid-level languages such as , Wordstar, DBase, Forth etc. Language cis very helpfull to ‘make compli or system program ** Low-level Language: Both Machine language and Assembly language are called together Low-level language. ‘The language, which is directly understood by computer, is called the machine language of computer. This “Machine language of computer is made according to binary number sytem. By using Assembly language to make the binary instructions of machine language merely short ha been possible. That means in tis method computer Is made understand the group of bit expressing in special code (Mnemonic code) by English letter. These codes ae called Assembly code or Assembly language. Top of the low-level languages are Macro assembler and Assembler. ‘© Advantages (Low-Level Language): (2) Program can be written inthis language by using lowest number of logical memory space. (2) Knowledge of low-level language is needed most to achive ideas about inner organization of computer. (3) Functions by this language i very fast. (© Disadvantages (Low-Level Language) : (2) Program writing inthis language is very hard and time needed mater. Because fillidea is needed about real condition of memory space for every instruction. (2) Weitten program fora type of machine cannot be used in another machine. (3) This language is hard to keep in one's memory. (4) Errors of program are very hard to identiy {5} Computer cannot directly execute low-level language. ** Compiler: Compiler isa special kind of program or translator software by which, program written in high-level language can be translate into machine language. Computer cannot understand any language except its own, ‘machine language, But for program writing in high level language words letter, symbol of general English language are used. At fist compiler examines high-level language program top to bottom and if there sno wrong compli turns the whole program into machine language. Program written in high-level language is called source code and program turned to machine language is called object code. Program translated by compiler can be execute as. times we need, There i different compiler for every programming language. We cannot translate a program by the compiler of another program. 15 HAPTER GINTRODUCTIONT COMPUTERS) Interpreter translates high-level language to machine code, But lke compiler, Interpreter does not translate whole program inta machine language at atime. interpreter translates jus a line of program written in high-level language into machine language and executes it. Here any executable files not creating. Asa result ‘rogram turned into machine code cannot be run without the help of proper interpreter ** Pseudo code : Pseudo code s a popular system in writing and improved of program, Pseudo is a Greek word. Pseudo means what isnot real. Many programmers would to do pseudo code for programming. Is easy to say that pseudo code is pseudo program. Pseudo code is really preparation before algorithm or is an alternative of algorithm. Agreement of some instructions or statements about type and function of program is called pseudo ‘code. Pseudo program or pseudo code Is prepared before final program or algorithm. it may need to prepare pseudo code one after another for having final algorithm. Algorithm may be final after revision and amplification. But there are many programmers who can go directly to write program from revised pseudo program. They use pseudo program as alternative of flowchart. Such a work is only possible to expert programmer. ** File Processing : By Read statement we can read data from any prepared data file. Again we can write out put data in new or od file by Write statement. Data file used for reading is called input datafile and fle used for ‘writing is called output datafile Various processing to open, read or to write input datafile and output data fle are calle file processing . it he literal meaning of batch sa group ora set of similar things (obs). In batch processing ‘the user submits ajob or a group of obs to the computer. The computer will process these jobs one at atime. A new job will not be processed until the previous job Is completed. The execution ofa group of jobs one-after another and automaticaly, is called batch processing. The time of processing Is predetermined and depends ‘mainly on the operational role of the batch of transactions within the computer. The computer executes each of the jobs separately with the help of certain batch fe. “** Debugging ; it may occour various types of errors atthe ime of programme writing such a logical error, writing eror, symbolic eror, syntax eror, runtime error ete. These may cause trouble for computer to translate orto execute program. In this situation a ist errors are identified and then those are managed tobe corrected. ‘This procedure of correction is called making free from bug or Debugging. On other words errors in program is called bugs, and the process of locating and eliminating them i called debugging. {1) Syntax error: A syntax error i an error thats encountered when the programmer or individual who wrote the code has not followed the rules of the language, causing the program to fal thats rrorsin spelling an grammar |s the syntax error. By using the compiler oF Interpreter we can uncover the syntax errors. A good working knowledge of error messages is required to discover the cause ofthe erro. (2) Run-time error: An error that occurs during the execution of a program. Run-time errors indicate bugs inthe program or problems thatthe designers had anticipated but could do nothing about. The tuntime error message ‘canbe caused by: ‘) Conflict with other running program b) Software issue ) Computer virus ) Memory issue. For example, running out of memory will after cause a runtime error. (3) Logial error: An error that indicates the logic used when coding the program falled to solve the problem. A logical error will not cause the program to stop working, it can produce incorrect result. We do not get error ‘messages fo logical errors. Production of wrong solution is only the clue of logical ero. (4) Compile-time error: An error that occurs while a program is being compiled. Compile-time error is detected by the compiler before the program is started. Type checking, storage allocation and even code generation and, code optimization may be done at compile-time or at run-time, depending on the language and compile. 4 Neein gabe a: ae iis Differences between Digital 1A computer that counts the numbers and works licectly on gls that represents either discrete ‘daa oF symbols called Digital computer 2. The funtion of digital computer forwarding and period, 3 Results ao dsplayed on monitor and en printed. ve 4 This computes used extensively nthe wphere ‘of education, treatment, business administration, recreation ee GWAPTAR = ORTEDDUCTION TO SOMPUTER between Digital computer and Analog computer: nd Analog computer are as below ‘Analog Computer TA computer that can measure continuous physical ‘quantities and convert them to analogous decimal or ‘oglcal operation and accomplished result is visible by mater oF Indicator i called Analog computer, 2, Tho method of measurement is to the funetion of analog computer, ile wot trough indieator or meter or boy graph (dra with plotter machine 4, This computer Is used in chemical, petroleum and food processing industries 5 Its comparatively free from error, dependable and speedy. ‘rit is Teas dependable and less speedy than digital computer, ta computers for general vie, ‘6. Analog computer I for specil 7 its application program can easily be charged ‘on the basic of work. 7. This i not $0 ‘Letter, umber, signal, symbol ete are used a Lnput in aigtal computer. __| voltage ete itference Softwore: Differences between Hardware and Software are given below: W Gieereal eu Tena temperature, pressure, (used as Input In analog computer, “Sofware Hardware T: Hardware refers to the physical components of@ computer. "TSaftware represents the programs, which onain @ st of Instruction 2 tis the body of computer system. 2. its the braln of computer system. pares computes bereaved Gono | 3 iarot ps vfs cn be vad damage oF for improve the performance. ‘according tothe necessity of user. 4 can be touched. Ttean't be touched. 5. Hardware is vis . Software is inviible power, 6. Example: Monitor, mouse ete. 6 MS office, Adobe 9p, DOS, Windows ete. 7 Hardware i breakable, 7, Software is non breakable, 8. itismade by metals. Its coded by different computer lnguages. ** Distinguish between RAM and ROM: Distinguish between RAM and ROM are a follows HLcUaonbsakiee donor cece spe ated at T.ROM Is permanent memory of» computer, When ‘computer io or electrity Is gone all the data of it | is deleted. Is not deleted of unchanged. ‘Data stored in ROM can be revised 2. But at ROM none can do such thing. [3.ttis power dependent, i. depends on elactricky. | 3. itis not vo. 4. The ager sn eed ot cy 4. This is Read Oniy Memory. ance of a computer onthe 3. ‘of 8 computer does not depend on pci a cn de nn pty ROM. There is no scope of adding ROM ike RAM. ‘6. Programs or data written by any user are: ‘until the shut down postion of a computer, ‘6, Data written by manufacturing company ae stored ‘permanently in ROM. sites ith CamScanne: * Difference between Digital 3! computer and Analog computer Differences between Digital and Analog computer areas below: CHAPTER 0 ONTRADUSTIONT9 COMPUTERS Digital Computer ‘Analog Computer T.Acomputer that counts the numbers and works directly on digits that represents ether discrete data or symbols is called Digital computer. T Acomputer that can measure continuous physical ‘Quantities and convert them to analogous decimal or logical operation and accomplished result is visible by meter of indicator is called Analog computer. The function of digital computer i forwarding and periodical. 2. The method of measurement isto the function of analog computer. +3, Results are displayed on monitor and can be inted. 3, Results are visible got through indicator or meter or by graph (draw with plotter machine) 4, This computer is used extensively the sphere ‘of education, treatment, business administration, recreation etc. “4. This computer is used in chemical, petroleum and food processing industries 5. tis comparatively free from error, dependable “itis Tess dependable and less speedy than digital ‘on the basic of work. and speedy. compute. 6, Digital computer Is for general uses. 6. Analog computers for special uses. 7 Rs application program can easly be changed | 7. This snot so. 8 Letter, number, signal symbol etc. are used as Input in digital computer. Tf Electrical current, length, temperature, pressure, | vottage et. are used as input in analog computer. ** pifference between Hardware ond Software: Differences between Hardware and Software are given below: Hardware Software TL Hardware refersto the physical components ofa computer. T Sofware represents the programs, which contain @ set of instructions, 2. tis the body of computer ater 2. tis the brain of computer system. 53. Spare pars of computers can be replaced due to damage of for improve the performance. 3. Different types of software can be installed according to the necesity of user. 4. tcan be touched. 4. ean be touched. 5. Hardware is visible 5. Sofware i invisible power. 6. Example: Monitor, Keyboard, mouse ete. 6. Example: MS Ofice, Adobe Photoshop, DOS, Windows et. 7 Hardware i breakable 7. Software isnon-breakable, [B.ttis made by metals. tis coded by diferent computer languages. ** Distinguish between RAM and ROM: Distinguish between RAM and ROM are a follows : RAM RAMI temporary memory of a computer. When ‘computer is off or electricity is gone all the data of ROM is permanent memory ofa computer When it_| computers off or electricity is gone all the data of it isdeleted. is not deleted of unchanged. 2, Data stored in ROM can be revised. 2. But at ROM none can do such thing. 3. [tis power dependent, Le. depends on electrieiy. | 3. Itisnot so. 4. This memory canbe read or writen. 4. This is Read Only Memory. 5. Performance ofa computer depends on the capacity of RAM can be added for increasing capacity. 5 Performance ofa computer does not depend on ROM. There's no scope of adding ROM like RAM. 6. Programs or data written by any user are stored until the shut down position of a computer. 6, Data written by manufacturing company are stored permanently in ROM. S.Nazia Jahan 18 
