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COMPUTER SCIENCE PROJECT WORK FOR III UNIT TEST COMPUTER SCIENCE PROJECT WORK FOR III UNIT TEST

MADE BY: AMIT KUMAR BHIM KUMAR CHITRANJAN GUIDED BY: MR. LOKESH SAINI 2 MADE BY: AMIT KUMAR BHIM KUMAR CHITRANJAN GUIDED BY: MR. LOKESH SAINI 2

History Of Computing n. Computer Hardware n 3 History Of Computing n. Computer Hardware n 3

v. Overview Computer Development Computer architecture 4 v. Overview Computer Development Computer architecture 4

v. Introduction n Computer is arguably the most important tool in the areas of v. Introduction n Computer is arguably the most important tool in the areas of engineering, science, business etc. n n Data acquisition and analysis Simulation Embedded applications n Process control n Condition monitoring and fault diagnosis systems n Automatic testing equipment n Robotics n Telecommunications Productivity software (word processing, spreadsheets, databases, presentation) etc…………… 5

v. Computer development n n The Abacus- Babylonia-4 th century B. C. The Difference v. Computer development n n The Abacus- Babylonia-4 th century B. C. The Difference Engine- Charles Babbage 1822 Vacuum tube - John Ambrose Fleming 1904 The ENIAC (Electronic Numerical Integrator and Computer)-1945 n Used 17, 478 vacuum tubes n Too late for WW-II, but was used in the cold war to perform calculations to build a hydrogen bomb 6

n n City of Philadelphia reportedly experienced brown-outs when ENIAC drew power at its n n City of Philadelphia reportedly experienced brown-outs when ENIAC drew power at its home at the University of Pennsylvania (http: //www. pbs. org/wgbh/aso/databank/entries/dt 45 en. html) Was not a general purpose computer: programming meant rewiring with punch cards and switches One of ENIAC's greatest feats was in showing the potential of what could be accomplished in the future Transistor - Nobel prize in physics in 1956 7

n n n Integrated Circuit (chip) - Jack Kilby 1958 (Nobel prize in physics n n n Integrated Circuit (chip) - Jack Kilby 1958 (Nobel prize in physics in 2000) First commercially available IC’s developed by Texas Instruments and Fairchild semiconductor corp. Apple I computer (1976) Generations of IC’s: n n n Small scale integration - 1965 n Up to 100 devices on a chip Medium scale integration - to 1971 n 100 -3, 000 devices on a chip Large scale integration - 1971 -1977 n 3, 000 - 100, 000 devices on a chip Very large scale integration - 1978 to date n 100, 000 - 100, 000 devices on a chip Ultra large scale integration n Over 100, 000 devices on a chip 8

Moore’s Law: Number of transistors on a chip will double every 18 months. 9 Moore’s Law: Number of transistors on a chip will double every 18 months. 9

v. Computer Architecture Central Processing Unit Main Memory Systems Interconnection Input Output 10 v. Computer Architecture Central Processing Unit Main Memory Systems Interconnection Input Output 10

Components of a Computer System Storage (External memory) input/output central processing unit Main Memory Components of a Computer System Storage (External memory) input/output central processing unit Main Memory (RAM) 11

Computer Components 12 Computer Components 12

Component description n n Central Processing Unit (CPU) or microprocessor, controls the operation of Component description n n Central Processing Unit (CPU) or microprocessor, controls the operation of the computer and performs its data processing functions Main memory - also called internal memory stores instructions and data. Memory is partitioned into separate instruction and data spaces Input/output (I/O) – moves data between the computer and its external environment System interconnection – some mechanism that provides for communications among the CPU, the main memory, and the I/O devices 13

Structure of the CPU storage input/output control unit ALU registers flags memory cache memory Structure of the CPU storage input/output control unit ALU registers flags memory cache memory 14

Components of the CPU n n Arithmetic and Logic Unit (ALU): processes the data Components of the CPU n n Arithmetic and Logic Unit (ALU): processes the data in the registers according to instructions issued by the control unit. Performs arithmetic (addition, subtraction, etc. . ) and logical (comparison) operations Registers: provides temporary storage for data and instructions. It handles instructions and data at 10 times the speed of cache memory. Registers facilitate the movement of data and instructions between RAM, the control unit and the ALU n Control unit registers: n The instruction register contains the current instruction being n n executed The program register (instruction pointer) contains the RAM address of the next instruction to be executed ALU registers n The accumulator register stores the result of ALU operations 15

n n n Internal CPU interconnection: some mechanism that provides for communication among the n n n Internal CPU interconnection: some mechanism that provides for communication among the control unit, ALU, and registers Control Unit: controls the operation of the CPU and hence the computer. Interprets instructions, moves data to/from memory and registers, instructs ALU to perform certain operations, increments instruction pointer, etc. During program execution, instructions in a program are moved from the RAM into the control unit, where it is decoded and interpreted by the decoder Flags: 1 -bit memory, or 1 -bit registers and hold information on what has recently happened in the CPU. These are set to 1 or 0 depending on the results of internal operations such as results of ALU operations (zero or negative result) or external operations such as interrupts (commands that tell the processor to stop execution and wait for further instruction) 16

n Cache Memory: Small fast memory that improves CPU’s efficiency. Increases computer throughput, and n Cache Memory: Small fast memory that improves CPU’s efficiency. Increases computer throughput, and is a high-speed holding area for program instructions and data. It holds only instructions and data that are likely to be needed by the CPU. While programs are running on the computer, the same data or instructions might be needed frequently. In such cases, the processor first checks the cache memory for the data or instructions, thereby reducing the need for frequent access to the RAM and speeding up the processing 17

Microprocessor System Buses Control Bus RAM ROM Microprocessor (CPU) Data Bus Address Bus Input/Output Microprocessor System Buses Control Bus RAM ROM Microprocessor (CPU) Data Bus Address Bus Input/Output (I/O) 18

System Buses n n A BUS is an internal communications path consisting of a System Buses n n A BUS is an internal communications path consisting of a number of lines connecting the system components Control bus –The control bus synchronizes system events like memory access, system interrupts, I/O, etc. Address bus – Source and destination addresses are sent over the address bus to identify a particular location in memory or input/output port. Data bus – two way path for transferring data and instructions in and out of the microprocessor 19

Main Memory n n n A collection of cells Each cell has an address Main Memory n n n A collection of cells Each cell has an address and a value Random Access Memory (RAM) Cells can be accessed randomly Ram is volatile All data stored in binary format Bit, byte and word are the unit of data 20

Main Memory n RAM – Random Access Memory. Temporary read/write memory. Applications are typically Main Memory n RAM – Random Access Memory. Temporary read/write memory. Applications are typically loaded into RAM during computer use. Types of RAM include: n SRAM (static) , DRAM (dynamic ), EDO RAM (extended data out) , SDRAM (synchronous dynamic-most new PC’s are equipped with this RAM which is able to synchronize itself with the processor, enabling data transfer at more than twice the speed of previous RAM technologies) n n SRAM is called static because the memory retains its contents as long as power is supplied-It does not have to be periodically refreshed as in DRAM. It is faster than DRAM (The contents of the memory can be read much faster), however is more expensive and is larger in size DRAM is called Dynamic RAM because the memory content needs to be refreshed periodically (every few milliseconds) due to leakage of electrical charge. It is slower than SRAM, but cheaper and smaller in size 21

CPU-Memory Interaction Fetch-execute cycle 0 LDA 14 1 ADD 15 Assume a is stored CPU-Memory Interaction Fetch-execute cycle 0 LDA 14 1 ADD 15 Assume a is stored in 14 and b is stored in 15 Program 2 STA 14 3 HLT …. …… 14 10 14 17 15 7 a= a + b Result 22

n ROM – Read Only Memory. ROM can typically be written once, but read n ROM – Read Only Memory. ROM can typically be written once, but read many times. It is used to store BIOS (Basic Input/Output System-helps to load and locate an operating system), external to microprocessor, and computer instruction sets, internal to microprocessor n n The contents of the ROM are hard wired by the manufacturer in a typical ROM chip. When you turn the computer on, ROM automatically prepares the computer system and loads the initial display screen prompt A variation of ROM is PROM (Programmable Read Only Memory), in which the user can load programs and data that are read only. This can be done with device called a PROM programmer. Writing to a PROM destroys the internal links, so a basic PROM can only be programmed once 23

n n n EPROMs (Erasable Programmable Read Only Memory) is a variation of PROM, n n n EPROMs (Erasable Programmable Read Only Memory) is a variation of PROM, and is rewritable. It can be erased by exposing the chip to ultraviolet light. It can then be programmed with an EPROM programmer Flash memory is a type of PROM that can be easily altered by the user. They are also called EEPROMs (Electrically Erasable Read Only Memory) because they can be electrically erased then written on to (flashed) without having to take them out of the computer, and without using ultraviolet light. Since RAM can be read faster than most ROMs, the frequently used content of the ROM is sometimes copied to RAM (shadowed) 24

Secondary Storage n Magnetic disk n n Optical media n n Hard disk (File, Secondary Storage n Magnetic disk n n Optical media n n Hard disk (File, Directory, Folder) Floppy disks Zip disks CD (680 MB) DVD (4. 7 GB) Magneto-optical disks (Pinnacle drives) Magnetic tape (used primarily for long term archive) 25

Hard Disk Drive Basics 26 Hard Disk Drive Basics 26

Input/Output Some Input Devices n n n Keyboard Keypad Mouse Voice activation Touch screen Input/Output Some Input Devices n n n Keyboard Keypad Mouse Voice activation Touch screen Digitizers and pen-based (stylus) systems 27

Some Output Devices n n n Monitor Printer Speakers Communication (comm) ports Modems (both Some Output Devices n n n Monitor Printer Speakers Communication (comm) ports Modems (both input and output) Network interface cards (both input and output) 28

Input and Output Devices and Systems 29 Input and Output Devices and Systems 29

Storage System Issues n n n n n Historical Context of Storage and I/O Storage System Issues n n n n n Historical Context of Storage and I/O Secondary and Tertiary Storage Devices Storage I/O Performance Measures Queuing Theory Processor Interface Issues I/O Buses Redundant Arrays of Inexpensive Disks (RAID) File Systems I/O Benchmarks File System Performance 30

n Input device is a tool used to capture information and commands n Examples n Input device is a tool used to capture information and commands n Examples include: n n n n n Keyboard Point-of-sale (POS) Microphone Mouse Pointing stick Touch pad Touch screen Bar code reader Optical mark recognition (OMR) Scanner IT Fundamentals 31

Types of input IT Fundamentals 32 Types of input IT Fundamentals 32

Input Devices Most obvious = human + KEYBOARD Need to be: Accurate, reliable and Input Devices Most obvious = human + KEYBOARD Need to be: Accurate, reliable and easy to use, fast Human and keyboard is the most used input device Machines make better input devices…. DIRECT ENTRY, or SOURCE DATA AUTOMATION. IT Fundamentals 33

Examples of Direct Entry Input Devices Scanners MICR : Used with cheques OMR : Examples of Direct Entry Input Devices Scanners MICR : Used with cheques OMR : Tattslotto & TAB OCR : Scan type-written pages…. IT Fundamentals 34

Examples of Direct Entry Input Devices Barcode Readers: Sit-in-the-Counter type Reads standard or customised Examples of Direct Entry Input Devices Barcode Readers: Sit-in-the-Counter type Reads standard or customised barcodes IT Fundamentals 35

Input Types Data Collection Devices: Web Cams Video camera whose output displays on a Input Types Data Collection Devices: Web Cams Video camera whose output displays on a web page Digital Camera a. IT Fundamentals 36

Other Input Devices Sensors Pointing Devices Mouse measures x-y moveent plus whether button is Other Input Devices Sensors Pointing Devices Mouse measures x-y moveent plus whether button is pressed down… a. IT Fundamentals 37

Other Input Devices Trackball - Similar to mouse Joystick - games? Difficult to pinpoint Other Input Devices Trackball - Similar to mouse Joystick - games? Difficult to pinpoint a position Touch screens screen 'divided' into areas area selected by touch easy to use cannot have areas too small screens get dirty (many uses) Touch. Pad Pointing Stick Light Pen IT Fundamentals 38

Voice Input IT Fundamentals 39 Voice Input IT Fundamentals 39

Output Four common type of output are text, graphics, audio and video. IT Fundamentals Output Four common type of output are text, graphics, audio and video. IT Fundamentals 40

Output Devices Digital signals from computer are converted into human readable form. Hard Copy Output Devices Digital signals from computer are converted into human readable form. Hard Copy Soft Copy IT Fundamentals 41

Output Printers Impact printers Dot Matrix: IT Fundamentals 42 Output Printers Impact printers Dot Matrix: IT Fundamentals 42

Output Non-impact printers ink jet - no physical contact between paper and printing device Output Non-impact printers ink jet - no physical contact between paper and printing device 3 technologies used: thermal - special paper expensive to run up to photographic quality… IT Fundamentals 43

Output Laser - need enough memory to hold an entire page 600 to 2400 Output Laser - need enough memory to hold an entire page 600 to 2400 dpi and greater operates similar to a photocopy machine… IT Fundamentals 44

Output CRT Monitors • Raster scan technology • An electron beam moves back and Output CRT Monitors • Raster scan technology • An electron beam moves back and forward across the back of the screen • This causes dots on the front of the screen to glow, producing an image • Available in various sizes 15 – 22 inches • Flat and curved screens Resolution • CRT monitors ( 1280 X 1024 pixels) • High end CRT monitors (2048 X 1536 pixels)…. IT Fundamentals 45

Output IT Fundamentals 46 Output IT Fundamentals 46

Output LCD Monitors • An electric current passes through the crystals causing them to Output LCD Monitors • An electric current passes through the crystals causing them to twist, block light waves and create an image. Gas Plasma Monitors Very high quality (1080 p)…. • Larger screens IT Fundamentals 47

Other Output Devices Data Projectors IT Fundamentals 48 Other Output Devices Data Projectors IT Fundamentals 48

Other Output Devices Fax Machine • Transmits and receives documents over the telephone line Other Output Devices Fax Machine • Transmits and receives documents over the telephone line IT Fundamentals 49

Other Output Devices Multifunction devices • Printer, scanner, copy machine and fax machine all Other Output Devices Multifunction devices • Printer, scanner, copy machine and fax machine all in one IT Fundamentals 50

SECONDARY STORAGE Control Unit works on programs/data in RAM POWER OFF. . . RAM SECONDARY STORAGE Control Unit works on programs/data in RAM POWER OFF. . . RAM OFF Bye Assignment However blocks of memory can be saved/read on secondary storage. 51

SECONDARY STORAGE Secondary Storage Media and Devices Floppy Disks Hard Disks Tape and Tape SECONDARY STORAGE Secondary Storage Media and Devices Floppy Disks Hard Disks Tape and Tape drive Cartridge tape CD-ROM/DVD/Blu. Ray Magnetic-Optical drive PC Cards Smart Cards USB Drives 52

FLOPPY DISKS: • • 3 1/2 -inch diskette Circular piece of plastic Made up FLOPPY DISKS: • • 3 1/2 -inch diskette Circular piece of plastic Made up of tracks & sectors 512 bytes in each sector Size Type IBM: 3½ DD 3½ HD Macintosh 3½ HD Tracks Sectors Capacity 80 80 9 18 720 KB 1. 44 MB 1. 4 MB eg. for a 3½ disk (high density): 53

HARD DISKS • Made up of platters, cylinders and sectors • Rotation speed 7200 HARD DISKS • Made up of platters, cylinders and sectors • Rotation speed 7200 rpm • head 'floats' on surface • bad sectors & head crash 54

Hard Disk Vs Floppy Disk OPTICAL STORAGE TECHNOLOGY • CD-ROM (compact disk read-only memory)- Hard Disk Vs Floppy Disk OPTICAL STORAGE TECHNOLOGY • CD-ROM (compact disk read-only memory)- 650 MB of information • DVD (digital video disk) - 4. 7 gigabytes • CD-R (compact disk-recordable) • CD-RW (compact disk-rewritable) • Magneto-optical (MO) – combines magnetic/optical technology by changing polarity of spot (1 to 0 etc. ) 55

CDROM • Compact Disk Read Only Memory • high capacity is ideal for storage CDROM • Compact Disk Read Only Memory • high capacity is ideal for storage of the very large sound, graphics and video files • when recording data, laser light burns pits on CD • when reading data, pits will not reflect light (binary bit 0) but lands will reflect light (binary bit 1) 56

Other Storage Devices Tape • Thin ribbon of plastic • Sequential storage – mainly Other Storage Devices Tape • Thin ribbon of plastic • Sequential storage – mainly for backup • Used for longer term storage USB Flash Drives • plugs into a USB port • Small, lightweight • Storage 4 GB + • Great for mobile users 57

OTHER TYPES OF STORAGE DEVICES PC cards • Small, credit card-sized cards that fit OTHER TYPES OF STORAGE DEVICES PC cards • Small, credit card-sized cards that fit into PC Card expansion slots • Used for storage, communications and additional memory. • Most often used with portable computers • Can store more than 300 MB of data Smart Cards • Credit card-sized devices that contain a microprocessor • Microprocessor can store up to 8, 000 bytes of information. • Examples of uses - prepaid telephone card, employee time card 58