**GE6151 COMPUTER PROGRAMMING**

Transcription

1 UNIT 1 INTRODUCTION TO COMPUTERS 1. What is a computer? The computer is an electronic machine that takes input from the user and processes it to generate the output in the form of useful information. 2. What is a program? A program is a set of instructions that can be executed one-by-one in the computer. Each program performs certain task that is created by the user. 3. What is Hardware and Software? Hardware of the computer means, all the visible components of a computer that are needed for proper functioning. It is the framework. Software is applied on the hardware of the computer. E.x: CPU, monitor, etc Software of the computer means, the set of programs that can be executed one by one in a computer. It controls all the operations of a computer. Ex: OS, games softwares, etc 4. What is the difference between application software and system software? System softwares are inbuilt softwares that are required to start the computer. Without system software, a computer cannot work properly. Ex : Windows OS, Linux OS, DOS, etc Application softwares are optional softwares that are needed to perform certain task needed for user. Without application software, a system can work. Ex: Tally, Games softwares, etc 5. What are the advantages and disadvantages of first generation of computers? Based on vacuum tube technology During that time, these type of computers were the fastest. Calculations are done in milliseconds. Large space is needed. It takes more power Very costly No reliability Programming is difficult 6. What are the advantages and disadvantages of second generation of computers? Based on transistor technology Very costly Small in size It needed AC Less heat produced Production was difficult Calculations are done in microseconds Better reliability 7. What are the advantages and disadvantages of third generation of computers? Based on IC (Integrated Chip) technology It needed AC Calculations are done in nano seconds Production was difficult Less power needed Less maintenance cost More reliability 8. What are the advantages and disadvantages of fourth generation of computers? Based on Processor technology Production was difficult Small in size Portable and very much reliable Less maintenance cost All programming languages are supported 9. What are the advantages and disadvantages of fifth generation of computers? Portable User friendly Supports many OS Supports parallel programming High speed calculations Large storage capacity. There is no program that makes the computer to operate completely automatic. Page 1 of 11

2 10. What are the characteristics of a digital computer? They have large space They are suitable for business High processing speed Discrete value outputs are got It is versatile in nature. 11. What are the differences between analog and digital computers? Analog computer Digital computer Less speed High speed Less More Limited usage Many number of usage Output is in the form of graph Output is in the form of discrete values Less accurate calculation More accurate calculation 12. What are the advantages and disadvantages of micro and mini computers? Advantages Micro computers Disadvantages Mini computers Small in size Less capacity Very cheap in cost, compared to Mini computers Difficult in maintenance Highly reliable Advantages Mini computers Disadvantages Mini computers Small in size, compared to mainframe computers Calculation speed is less than mainframe computers Cheap in cost, compared to mainframe computers Memory capacity is small, compared to mainframe 13. What are the advantages and disadvantages of mainframe and super computers? Advantages mainframe computers Disadvantages mainframe computers Many OS can be installed in mainframe It is very much costly computer It can be used instead of 1000s of small servers Its size is very big It can store large amount of data Advantages super computers Disadvantages Super computers Processing speed is : trillions per second Its size is large Many processors can work at the same time It is also very costly It has more main 14. Compare RAM and ROM RAM ROM It is a volatile It is a non-volatile It is used for both READ and WRITE operations It is used for READ operation only It has small storage capacity It has large storage capacity It is temporary It is permanent Its cost is high It is cost effective Processing speed is high Processing speed is low 15. What is an algorithm? An algorithm is defined as a step by step procedure for solving a problem. It is a set of rules to solve a problem. 16. What are the characteristics of an algorithm? It has a finite number of inputs Every instruction is clear and short It should have a proper ending Each step should be important. Overall output should be got only after the algorithm ends. It should contain the steps one-by-one to solve the problem 17. What is a pseudo code? Pseudo = copy (or) Duplicate, Code = instructions It cannot be compiled or executed It is written in natural language such as English, etc It is used to concentrate on algorithm Page 2 of 11

3 18. What are the advantages and disadvantages of pseudo code? Advantages Disadvantages It can be easily prepared in Word processor It does not have pictures software Easily modified There is no rules for preparation It is simple because it is written in English It cannot be compiled or executed No confusing symbols are used No rules are followed It is easy to understand the problem 19. What is a flow chart? A flow chart is a diagrammatic representation that illustrates the operations to be performed one-by-one. It contains different symbols. 20. What are the advantages and disadvantages of flow charts? Advantages Disadvantages It is easy to understand It cannot be prepared for difficult programs A problem can be analysed easily with flowchart Alterations and modifications cannot be done easily It gives clear idea of a program It is not typed, so its preparation is little difficult It acts as a guide during the program development It helps to clear the errors in coding It helps in maintenance of code PART B 1. What are the characteristics of a computer? a. Speed:- Computers are very fast in processing They solve large problems in less time They are faster than humans They do millions of calculations per second b. Accuracy:- They perform calculations accurately; accuracy means, without any error They process large amount of data without error c. Storage:- A computer can store large amount of data in primary and secondary Storage is calculated in BYTES. 1 BYTE = 8 BITS. 1 BIT = 0 or 1 8Bits = 1 BYTE, 1024 Bytes = 1KB, 1024KB=1MB, 1024 MB = 1GB, 1024GB = 1TB d. Versatility:- Computers are versatile; versatile means, perform many works at same time They are used for doing arithmetic and logical operations e. Diligence:- They do not get tired even after performing many calculations They perform all the tasks with same accuracy and speed f. Automation:- The computers perform operations without stopping. They do the process one by one according to the instructions 2. What are the applications of a computer? It is used to store, display, send and receive information It is used to draw graphs, pictures It is used in medical clinic and labs It is used to control rockets and aeroplanes It is used for banking purpose also It is used in horoscope It is used in Crime investigation It is used to control Robots Page 3 of 11

4 Education:- It is used in education, online classrooms, online library, etc Marketing:- It is used in preparing advertisements Banking:- It is used in banking to store the account details of customers It is used in ATM, internet banking Video games:- It is used in playing video games, online games, etc Training:- Computers are used to give training to the workers Hospitals:- It is used in hospitals to help the doctors to find the disease and give treatment It stores the record of patients Ex: Scan, blood test, ECG, etc Railways:- It is used in online ticket reservation, see the schedule of trains, etc Science:- It is used in research by scientists It helps in finding earth quake, Tsunami, etc 3. Explain the generation of Digital computers in detail. (or) Explain the Generation of computers in detail. First Generation:- The first generation of computers were used only for certain task. Each computer has a machine language ( 0 s and 1 s) They are difficult to process They are not versatile, they have limited speed. They used VACUUM TUBES and MAGNETIC DRUMS for data storage. It consumed 100kW power, weight of many 1000kilos. It performed 5000calculations per second. Ex: EDSAC, UNIVAC, etc Based on vacuum tube technology During that time, these type of computers were the fastest. Calculations are done in milliseconds. Large space is needed. It takes more power Very costly No reliability Programming is difficult Second generation of computers:- They are used in business, university, government, etc because of its success. They used TRANSISTORS for storage They are small and consume less power Thermionic valves are used instead of heated tubes They also contained components such as printers, tape, disk storage,, OS, etc Ex: IBM 1401, 1620, UNIVAC 1108 Based on transistor technology Very costly Small in size It needed AC Less heat produced Production was difficult Calculations are done in microseconds Better reliability Page 4 of 11

5 Third generation of computers:- Integrated Chip (IC) Technology is used for storage Quartz rock is used to remove the heat. IC is a combination of three components on a small disc Semiconductor was also introduced. Because ICs are small in size, the size of the computers became small In this generation of computers, many operating systems can be installed. Ex: IBM 360 series, ICL 1900 series, CDC 1700 Based on IC (Integrated Chip) technology It needed AC Calculations are done in nano seconds Production was difficult Less power needed Less maintenance cost More reliability Fourth generation of computers:- IBM introduced Personal Computers (PC) that can be used in home / office / schools The size of the computer became still smaller Number of personal computers doubled from 1million in 1981 to 5.5million in 1982 After 10years, 65millions PC were used. Apple s MacIntosh OS also introduced in 1984, that is user friendly design. Ex: Intel 400L, Apple series I and II, IBM Based on Processor technology Production was difficult Small in size Portable and very much reliable Less maintenance cost All programming languages are supported Fifth generation of computers:- Many advances came in science and technology in this generation Parallel processing is used, it means, many CPU work as one CPU Superconductor technology is used in this generation Information flow is fast because of superconductor Ex: Expert systems help doctors to cure the patient s disease Artificial intelligence is a branch of computer science that makes the computers behave like humans Artificial intelligence is used in: Games, Expert systems, Natural language, Neural networks Portable There is no program that makes the computer to User friendly operate completely automatic. Supports many OS Supports parallel programming High speed calculations Large storage capacity. 4. Write the differences between analog and digital computers Analog computers:- Analog computers represent the data as physical quantities It performs operation based on measuring It is designed to process data of varying quantities It solves problems in voltage, current, etc They are useful in simulation and evaluation of dynamic situations It contains operational amplifier Computer s capacity is determined by number of amplifiers They are used in speedometres, watt-hour metres Ex: Electronic weighing scale, patient heart beat, blood pressure Page 5 of 11

6 Characteristics of analog computers:- Low speed Limited applications Less space Not suitable for business Output is not accurate Digital Computers:- They process the information digitally. It stored and processes the data in digital form Data is stored as 0 s and 1 s Output produced by digital computers is in Digital form. Ex: Palmtop, Laptop, Super computer, etc Characteristics of a digital comouter:- Large space Suitable for business applications Processor speed is high Versatile in nature 5. Explain about mainframe and super computers Mainframe computers:- It is an ultra-high performance computer, made for high storage. It contains high quality computer processor, processor, hardwares It is used for storing large volumes of data, highly important online transaction, etc It is very powerful and large computer Its operating speed is MIPS Million instructions per second Ex: IBM ES000, VAX8000, CPC6600 Advantages mainframe computers Disadvantages mainframe computers Many OS can be installed in mainframe It is very much costly computer It can be used instead of 1000s of small servers Its size is very big It can store large amount of data Super Computers:- They are most powerful computers than mainframe computers The simplified form of mainframe computer is called as super computer It is the top level computer used for high processing capacity It can process Trillions of instructions per second ( 10,00,000 = 1million, 10,00,00,000=1trillion) Applications of super computers:- This computer cannot be used at home It is used in heavy jobs such as Government use, etc They are useful in weather forecasting. Advantages super computers Disadvantages Super computers Processing speed is : trillions per second Its size is large Many processors can work at the same time It is also very costly It has more main 6. Explain the basic organization of a computer. The organization of a computer has four major parts:- They are a. Input Unit b. CPU c. Output Unit d. Memory unit Page 6 of 11

7 Input Unit Memory Unit Output Unit Cache Registers ALU CPU Control Unit Basic operations of a computer:- It ACCEPTS the data or instruction through INPUT It STORES the data or information It can PROCESS data as instructed by the user It GIVES results through OUTPUT It CONTROLS all the operations Input Unit:- Input devices get the data from the user and converts to the machine understandable form. Ex: Keyboard, Mouse, Scanner, Joystick, Lightpen, Card reader, Webcam, Microphone Keyboard:- It is a standard input device attached to all type of computers It contains keys arranged in the form of QWERTY It contains many keys such as TAB, CAPSLOCK, SPACE BAR, ALT, CTRL, ENTER, HOME, END, etc It contains 101 to 104 keys If we press the keys in the keyboard, electrical signals are sent to the computer. Mouse:- It is used with personal computer Old type of mouses have magnetic ball at the back. Nowadays, Infrared mouses are used, that works on infrared light at the back of the mouse We can move cursor to any direction with the help of a mouse It is used for easy and fast operations. Scanner:- Keyboard can give input only the characters Scanners can give a picture as input to the computer Scanner is an optical device that takes a picture and gives as input to the computer Ex: MICR, OMR, OCR MICR Magnetic Ink Character Recognition They are used in bank cheques Magnetic ink is printed on the cheque. If the cheque is passed through magnetic field, the information is read OMR Optical Mark reader They are used in objective type tests Students have to shade the rounds for the correct answer OCR Optical Character Recognition Reads a paper and takes the information from it, gives as input to the computer They are costly than MICR Joystick:- It is an online device We can move the cursor fastly with the help of joystick They are used to play games, etc Page 7 of 11

8 Light Pen:- It is a light-sensitive device It is used with CRT monitor It is used in CAD Using light, it moves the cursor Photo-sensor is used Card Reader:- It was punched cards to give information to the computer The computer program which is to be fetched, transformed into punched cards by the process known as card punching After punching all cards, they are given to card reader, computer reads one by one Webcam:- It is a video camera that gives image or video to the computer that can be transferred online It is connected to the system with USB cable It us used for video chatting, video conferencing, etc using WWW Microphone:- It is an acoustic-to-electric transducer or sensor that converts sound signals to electric signals They are used in Telephones, hearing aids, recording audio engineering, Radio and TV broadcasting, etc It uses electromagnetic inductance capacitance change to produce electric signal from mechanical vibration CPU:- It is called as brain of the computer It performs taks such as arithmetic and logical operations CPU is divided into three parts: ALU, Control Unit, Registers ALU:- After the system gets input data, it is stored in primary storage. The actual processing of data takes place at Arithmetic Logic Unit (ALU) It performs addition, subtraction, multiplication, division, logical comparison, etc It also performs AND, OR, NOT, XOR, etc operations Control Unit:- It acts like the supervisor of a computer It controls the overall activities of a computer components It checks all the operations of a computer are going correctly or not It determines how the instructions are executed one by one It controls all the input and output operations of a computer For executing an instruction, it performs the following steps:- o Address of the instruction is placed in address bus o Instruction is read from the o Instruction is sent for decoding o Data from that address is read from the o These data and address are sent to the o Again the next instruction is taken from the Registers:- They are high speed units for storing temporary data they are small in size it stores data, instruction, address, etc ALU is also a register Types: Accumulator, GPR, SPR( PC, MAR, MBR, IR) Accumulator: to store the operands before execution. It receives the result of ALU operation GPR: General Purpose Registers are used to store data and intermediate results SPR:Special Purpose Registers are used for a certain purpose. PC: Program counter, MAR: Memory Address Bus, MBR: Memory Buffer Register Output Unit:- It is a medium between computer and the human After the CPU finishes operation, the output is displayed in the output unit They take the input from CPU and converts to human readable form Types of output:- Hardcopy, softcopy Hardcopy: The output that can be seen physically using a printer is called as hardcopy Page 8 of 11

9 Softcopy: The electric version of output that is stored in a computer or a card, or a hard disk Ex: Monitor, Printer, Plotter Monitor:- It is the most popular output device It is also called as Visual Display Unit (VDU) It is connected to a computer through a cable called Video cord It can be monochrome or color monitor LCD: Liquid Crystal Display monitors o They are flat type of screen. Liquid crystals are used for display in the screen CRT: Cathode Ray Tube monitors o They are old-fashioned TV set like monitor Printer:- The output of a computer can be printed using Printer, to get the hardcopy Laser printer, Inkjet printer: Impact printers. They give fast printouts with good quality using LASER Dot matrix printer: non-impact printers. Their quality is poor, they are used for billing purpose Plotter:- They are used for printing graphics They are used in CAD/CAM Pen plotters take printout by moving a pen across the surface of a piece of paper Memory Unit:- Primary Secondary Magnetic core Semiconductor Thin-film Serial access Semi-random access RAM ROM Static RAM Dynamic RAM PROM EPROM EEPROM Primary storage:- It is a part of CPU Its storage capacity is limited It contains magnetic core or semiconductor cells It is used for temporary storage Magnetic core : o It contain a small dough-nut shaped objects made of ferromagnetic material o Current is passed through wire in one direction, magnetized in one direction Semiconductor : o It contains IC chips on silicon o They are small, high processing speed, low power is used, cheap, easy to assemble ROM: o Major type of in a computer is called ROM o Read Only Memory o It can be read, cannot be written o It is used for storing permanent values o ROM does not gets erased, even after the power is switched off o They are non-volatile ( information cannot be erased) Page 9 of 11

10 o We can store the important data into the ROM o Ex: Hard disk PROM: Programmable Read Only Memory They contain 1000 of fuses burnt, applying 12V to the boxes These fuses say 0 or 1 EPROM: Erasable Programmable Read Only Memory They can be deleted This chips have glass panel, UV rays are passed Fuses are rearranged in UV rays (all bits become 1) EEPROM:- Electrically Erasable Programmable Read Only Memory They can be erased using electric current RAM:- o They are used for storing programs and data that are executed o It is different from ROM o Random Access Memory o It can be read and written o It is volatile o When the power is turned off, its contents are erased o It is also called as RWM (Read Write Memory) o It is faster than ROM o Static RAM (SRAM) and Dynamic RAM (DRAM) are its types o Its cost is high o Its processing speed is also high Cache :- o It is a very small used to store intermediate results and data o It stores the data that are more frequently called for processing o It is present inside the CPU, near the processor o It is used for the faster execution Secondary Storage:- o The speed of primary is fast, but secondary is slow o But the capacity of primary is low. So, secondary is used o It contains large space o It is also called as additional or auxiliary o Data is stored in it permanently o Ex: Magnetic tape, Hard disk, Floppy, Optical Disc, USB drives o Magnetic tape:- It is used for large computers like mainframe computers Large volume of data is stored for a long time It is like a old tape-recorder cassette They are cheap They store data permanently Its diameter is 12.5mm to 25mm, length is 500M to 1200M It is compact, low cost, portable, unlimited storage, easy to handle o Hard disk:- Hard disks are disks that store more data and works faster It can store 10GB to 2TB It consists of platters Two heads are there for read and write It is attached to single arm Information in hard disk is stored in tracks A track location that cuts across all platters is called as a cylinder All platters have same no.of tracks o Floppy Disk They can store 1.4MB of data They are 5.25 to 3.5 inch in diameter They are cheap, portable Page 10 of 11

11 o Optical Disk:- CD-ROM: Compact Disk They are made of reflective material High power laser beam is passed to store data onto CD Cost is low, storage capacity is 700MB Its size is 4.5inches in diameter It can only be READ, cant be written Only a single side can be used for storage DVD: Digital Video Disk It is the improved version of CD It can store 4.7GB of data Both the sides are used for storage They cannot be scratched or damaged like CD USB drives:- They are commonly called as PEN DRIVES They are removable storage They are connected to the USB port of a computer They are fast and portable They store larger data when compared to CD, DVD (1GB to 64GB pendrives) Important example programs:- Example program 2 Example program 4 Example program 5 Example program 6 Example program 7 Example program 9 Example program 10 Example program 11 Example program 13 Page 11 of 11