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WELCOME
MIS – 104:
Computing Fundamentals
BBA Department of MISUniversity of Dhaka
3
Books
1. Introduction to Computer Peter Norton
2. Computer Fundamentals Dr. M Lutfar Rahman
3. Computer Fundamentals Pradeep K. Sinha
4
Previous class
>>Organization of computerInput UnitOutput UnitMemory unitControl UnitALU
Today’s Class
6
Output unit
>>Output UnitPrinterMonitorplotterSpeaker
Touch Screen
7
Printer
• Two types- Impact & non-impact
• Impacts are Type writers like dot matrix, line printer, drum printer
• Non-impact printer works by creating images like ink jet printer, laser printer, photo printer, Thermal printers.
8
Dot matrix printer: Mechanism
• Consists of print head which have a cluster (matrix) of short pins arranged in one or more columns
• Receiving command from the CPU, the print head pushes the appropriate pins in and out of its cluster
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Dot matrix printer: Mechanism
• Clusters in various combination can create various alphanumeric characters
• When pin is out of cluster, produced pin strike the ribbon and press ink on the paper
• The more pin in the cluster then higher the resolution
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Dot matrix printer: Advantages
• Can make carbon copies
• Lowest print cost per page
• Ink ribbon does not easily dry out
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Dot matrix printer: Dis-advantages
• Noise level is very high
• Resolution is very low
• Limited quality
• Limited color performance
• Low speed of printing
13
Laser printer: mechanism
• It uses laser light for printing mechanism
• Just as the electron gun in a monitor can target at any pixel, the Laser in a laser printer can aim at any point on the drum, cresting a electric charge
• The laser reflecting from the scanning mirror moving through the ‘beam alignment lens’ falls on imaging drum
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Laser printer: mechanism
• Toner contains tiny particles of ink strikes to the drum in the places the laser has charged
• Then with the pressure and heat, the toner is transferred off the drum onto the paper
• The amount memory used, determines the speed of printing.
16
Laser printer: Advantages
• Very high speed • No irritating sound like dot matrix printer• Low noise level• Low maintaince requirements• High quality image• Excellent graphics quality• A variety type of size and qualities• Monochrome printing speed: 4-16 ppm• Resolution: 300, 600 dpi (high quality: 1200-
1800dpi)
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Laser printer: Dis-advantages
• Printer is costly• Rough use can damage the lens and the
mirror• Toner is costly and need to be changed
after a thousand of page printed.
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Ink jet printers: requirements
• Requires the ink nozzle containing CMYK • CMYK (cyan-blue, magenta-red, yellow,
black)
• Also requires specially coated papers
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Ink jet printers: Mechanism
• Ink is exposed to UV radiation source where chemical reaction will take place
• A shuttered mercury vapor lamp is on either side of print head & produces a great amount of heat to complete the curing process
• UV do not evaporate rather cure
20
Ink jet printers: Mechanism
• Monomers due to UV ray forms polymer resulting high molecule which sets as a image on paper or plastic
• No material is removed that means 100% of delivered volume is used to provide colorization
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Ink jet printers: Advantages
• Do not need warm up time • Noise level is very low i.e. almost quite• Print finer, smoother with high resolution• Instant dry saves time• Printing Speed: 2-4 ppm• Resolution: 300 dpi, 600 dpi• Cartridge are less costly (than toner)• Most uses separate color cartridge and a BW
cartridge which saves ink.
23
Ink jet printers: Dis-advantages
• Relatively slow printing
• clogged jets when not used
• Very narrow ink jet nozzle can coagulate with dry ink at the head
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Output device: Monitor
• Categories based on the prime hardware used
• Cathode ray tube (CRT)Ex- typical monitors with heavy weight
• Flat-panel displayEx- LCD, LED etc
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Output device: Monitor
• Categories based on the color display• Monochrome: One color on a black
background
• Grayscale: Shades of gray on a white or off-white background
• Color: From 16 to 16 million unique colors
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Other kinds of monitor
• Paper-white display
• Electroluminescent (ELD) display
• Plasma/gas plasma display
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Monitor : Phosphor dots
• The only single unit dot which is responsible for the image display
• There are ‘three types’ of phosphor dots they are red, green and blue i.e. RGB
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Monitor : Pixel
• Pixel, short for picture element, is the smallest number of phosphor dots that the electron gun inside the monitor can focus on {01M pixel= 01 Million pixels}
• Three phosphor dots combine to form a single unit pixel
01 pixel
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Resolution
• The more you have pixels in your monitor you will be able to see the more clear and sharp image.
• This sharpness is called resolution• For more resolution you must have more
pixels per inch area on the monitor and minimum distance of dot pitch
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Refresh rate & Dot pitch
• Refresh rate: It is the number of times per second that the electron guns scan every pixel on the screen
• Dot pitch: The distance between the same color phosphor dots of the pixel
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Organization of (CRT)
• Its main part is a ‘cathode ray tube’. • At its one end there is a source of high
voltage.• There is a ‘magnetic coil/yolk’ ; which is used
to control the flow of electron• At the back of the screen there are ‘phosphor
dots’
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Mechanism
• Electron gun shoots streams of electrons at a high voltage towards the screen
• Magnetic coil controls the flow of electrons
• Phosphor dots on the back of the screen glow when the electron beam hit them
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Mechanism : Scanning
• Electron gun do not scan it randomly but in a designed fashion
• The electron gun scans from left to right • Then from top to bottom• Refreshing every phosphor dot in a zigzag
pattern
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Mechanism : Scanning
left right
top
bottom
Indicates pixel
35
Why TV is not used as monitor?
• Television display contains resolution which is just a half of computer monitor. So it cannot show output of computer operation.
• Resolution indicates the sharpness of an image determined by the number of pixels on the screen. TV contains only the half number of pixels than monitor, so the resolution
36
Advantages of CRT monitor
• Refresh rate is high
• Relatively low cost
• Viewing angle is more i.e. can be seen from different angle
37
Disadvantages of CRT monitor
• Large In size
• Not portable
• Requires a lot of power to run it
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Advantages of FLAT PANEL(LCD) monitor
39
Advantages of FLAT PANEL(LCD) monitor
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Advantages of FLAT PANEL(LCD) monitor
• the pixels are addressed in rows and columns
• The column and row wires attach to transistor switches, one for each pixel.
• The one-way current passing characteristic of the transistor prevents the charge applied to the pixel from draining between refreshes to the display image
41
Advantages of FLAT PANEL(LCD) monitor
• Small in size, small space requires
• Portable as weight is less than CRT monitor
• High resolution
• A little power consumption
42
Advantages of FLAT PANEL(LCD) monitor
• Small in size, small space requires
• Portable as weight is less than CRT monitor
• High resolution
• A little power consumption
43
Disadvantages of FLAT PANEL(LCD) monitor
• Low refresh rate
• Viewing angle is low
• Images can be difficult to see in bright light
44
Output unit: Speaker
• Speaker is well known output device usually outputs sound
• It is attached with the sound card of the computer
• Sound can be controlled by controller • Electric signal is converted and it changes
the air pressure outside which we call sound
46
Output device: Touch screen
47
Output unit: Plotter
• A output unit like printer used to print large size posters
• Requires specified paper and ink
• It takes a few hours to print the poster
48
Output unit: Plotter
Memory Unit
50
Memory
Memory: – One or more set of chips that stores data or
programmed instructions either temporarily or permanently.
Classification of memory:1. Primary memory2. Secondary memory
51
Location of different memories
ALU
MAIN MEMORYOR
RESISTERS
CONTROL UNITINPUT
UNITOUTPUT
UNIT
SECONDARY MEMORY
52
Calculations of storage capacity
01 BYTE (B) 08 bit
01KB 1024 B
01 MB 1024.1024 B
01 GB 1024.1024.1024 B
01 TB 1024.1024.1024.1024 B
53
Memory Terminologies
• Memory Address:– Memory locations are
identified by numbers 100
B
X
Y
A0000
0001
0002
FFFD
FFFE
FFFF
54
Memory Terminologies
• Memory Word:– When memory is read or written, a block of
bit is read or written instead of a single bit.
– The block is considered to be a unit of operation/processing
– A set of bit with which read/write operation is done in a certain storage device is called memory word
– Example: 08 bits or 01 Byte memory word clearly 01000000 (08 bits) represents 64 and its character is @; here, this digital 08 bits in combine known as a memory word
100
B
X
Y
A0000
0001
0002
FFFD
FFFE
FFFF
55
Memory Terminologies
• Destructive:– composed of capacitors, data disappears when
read operation is done, needs re-write operation to retain data
• Non-destructive: – reverse nature – Example: semiconductor, switch, flash memory,
pen drive
56
Memory Terminologies
• Volatile:– Type of memory where data remains only when
the power supply is on. – Ex-RAM
• Non-volatile:– here content remains even the power is turned off– Example: hard disk, floppy disk, flash drive etc
57
Memory Terminologies:Memory operation
• Memory store/write:– The process of storing or writing data at the
specific location of the memory– Data is stored as bits – Ex- CD writing operation
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Memory Terminologies:Memory operation
• Memory read: – Also called ‘fetch operation’– To read stored data or to process that stored data– A binary word is selected from a specific address
of memory and this is transferred to another device
– Example: To hear a song from CD or any drive
59
Memory Terminologies:Memory access
• Random access:– Any location of storage can be accessed at any
moment– Does not matter whether the desired access
location is too close or a far away– Consumes almost same amount of time– Found in primary and secondary memory
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Memory Terminologies:Memory access
• Sequential:– accessing a bit of information in a serial order,
one after another– Access time depends on the last
order/information execution time– Example: Off line storage such as playing a song
from magnetic tape
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Primary memory
• Includes RAM & ROM
• CPU access directly on this memory
• Normally volatile in nature
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Primary memory: RAM
• Central storage unit
• Volatile
• Temporary in nature
• Holds operating systems, application programme, data in current use
• Other name is (Read/Write) memory
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Different types of RAM
• S RAM- Exhibits data remanance but still volatile as data dissolves when turn off
• D RAM- Data disappears after a certain period automatically if it is not refreshed. This type of RAM needs periodically re-read or re-written. Ex- Z-RAM, TT-RAM, A-RAM
64
Primary memory: ROM
• Proportionally read operation is more than write operation
• Contains user programmed instructions like Bootstrap loader
• Non-volatile
• permanent
65
Different types of ROM
ROM
M ROM M ROM M ROM M ROM
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Secondary memory
• Auxiliary unit• Storing capacity is huge• Normally non-volatile
• Normally two types-1. Magnetic 2. Optical
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Secondary memory: Magnetic
• Variation of ‘Magnet polarity’ determines whether the bit will be 0 or 1
• Data write process is done by electromagnetic head
• Ex- hard disk, floppy disk, magnetic tape
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Secondary memory: Optical
• Variation of light reflection determines the nature of bits
• Data is written with the help of LASER or UV rays
• Ex-CD-R/RW, DVD-R/RW, BD-R
69
Memory address:
• It is a number or a set of digital number (bit/Bytes) in the memory
• This address specially represented by binary numbers
• Decimal, Octal, Hex-decimal numbers are also used for addressing
70
Virtual memory:
• When secondary memory is used as primary memory then this is called virtual
• Provide assistance to the RAM, by creating space for the great amount of data
• When RAM finishes it’s access, virtual memory vanishes
• Virtual memory can be selected by user
71
Cache memory:
• Small memory chip is attached between CPU & main memory
• Give the assistance to the resisters• Speed up the data process• Three types of cache memory is found e.g.
L1(CPU resident), L2 & L3 (mother board)
72
Resisters
• They are not the part of main memory but store data and pass as directed by CPU
• The size of the resisters which is sometimes called the word size,indicates the amount of data with which CPU can work/access.
• Ex- 32 bits processor means, 04 bytes data processing capability
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