It is for basic learning for class XI

1. c hapte r 16
Computer System
Organisation

2. INPUT OUTPUT AND MEMORY
DEVICES
 INPUT DEVICES
– KEY BOARD
– MOUSE
– JOYSTICK

3.  PRINTERS
 SPEAKERS

4. PRINTERS
IMPACT PRINTERS
– THERE IS MECHANICAL CONTACT
BETWEEN THE PRINT HEAD AND PAPER
NON IMPACT PRINTERS
– THERE IS NO MECHANICAL CONTACT
BETWEEN THE PRINT HEAD AND PAPER,
PRINTING WILL TAKE PLACE AS
DIFFERENT WAYS

5. IMPACT PRINTERS EXAMPLE
1. LINE PRINTERS
– DRUM PRINTER
CONSIST OF CYLINDRICAL DRUM ON
WHICH CHARACTERS ARE EMBOSSED
– CHAIN PRINTER
CONSISTS OF A STEEL BAND ON WHICH ON
WHICH THE CHARACTERS ARE EMBOSSED

6. DRUM PRINTERS

7. CHAIN PRINTERS

8. 2. CHARACTER
PRINTERS(SERIAL PRINTER)
– CHARACTER PRINTER PRINTS ONE
CHARACTER AT A TIME, WITH THE
PRINT HEAD MOVING ACROSS A LINE,
NORMALLY PRINT 30 TO 300
CHARACTERS PER SECOND..
– THERE ARE TWO TYPES
DOT MATRIX PRINTERS
– Printing haead contains a vertical group
(array) of pins.
– There are 9 pins in the print head,
bottom 2 used to lower case, others for

9. Dot matrix printers

10. LETTER QUALITY PRINTERS
– This type of printer will print full
characters not as the character made of
dots.

11. This lesson includes the following sections:
• Overview of Printers
• Dot Matrix Printers
• Ink Jet Printers
• Laser Printers
• Snapshot Printers
• Other High-Quality Printers

12. Overview of Printers
• Categorizing Printers
• Evaluating Printers

13. Overview of Printers - Categorizing Printers
Printers fall into two categories:
• Impact printers use a device to strike an inked
ribbon, pressing ink from the ribbon onto the paper.
• Non-impact printers use different methods to place
ink (or another substance) on the page.

14. Overview of Printers - Evaluating Printers
When evaluating printers, consider four criteria:
• Image quality – Measured in dots per inch (dpi). Most
printers produce 300 – 600 dpi.
• Speed – Measured in pages per minute (ppm) or
characters per second (cps).
• Initial cost – Consumer printers cost $250 or less, but
professional printers can cost thousands of dollars.
• Cost of operation – This refers to the cost of supplies
used by the printer.

15. Dot Matrix Printers
• How Do Dot Matrix Printers Work?
• Performance

16. Dot Matrix Printers -
How Do Dot Matrix Printers Work?
• Dot matrix printers are a common type of impact
printer.
• A dot matrix printer's print head contains a cluster
of pins. The printer can push the pins out to form
patterns in rapid sequence.
• The pins press an inked ribbon against the paper,
creating an image.

18. Dot Matrix Printers - Performance
• Lower-resolution dot matrix printers use nine pins.
Higher-resolution models have 24 pins.
• Speed is measured in characters per second (cps).
Some dot matrix printers print 500 cps.

19. Ink Jet Printers
• How Do Ink Jet Printers Work?
• Performance

20. Ink Jet Printers –
How Do Ink Jet Printers Work?
• Ink jet printers are an example of non-impact
printers.
• The printer sprays tiny droplets of ink onto the
paper.
• Ink jet printers are available for color and black-and-
white printing.

22. Ink Jet Printers - Performance
• Ink jet printers offer speeds of (2 – 4 pages per
minute ppm) and resolution (300 – 600 dots per
inch dpi), comparable to low-end laser printers.
• Ink jet printers are inexpensive and have low
operating costs.

23. Laser Printers
• How Do Laser Printers Work?
• Performance

25. Laser Printers –
How Do Laser Printers Work?
• Laser printers are non-impact printers.
• They use heat and pressure to bond particles of
toner to paper.
• Laser printers are available for color and black-
and-white printing.

27. Laser Printers - Performance
• Laser printers provide resolutions from 300 – 1200
dpi and higher.
• Black-and-white laser printers usually produce 4 –
16 ppm.
• Laser printers produce higher-quality print than
ink jet printers, but are more expensive.

28. Snapshot Printers
• Snapshot printers are specialized, small-format
printers that print digital photographs.
• Snapshot printers are fairly slow, and can be more
expensive to operate

29. Snapshot printers are popular among
digital camera users

30. Other High-Quality Printers
Print shops and publishers use these printers to create
high-quality color images:
• Thermal-wax
• Dye-sublimation
• Fiery
• IRIS
• Plotters

31. Plotters use mechanical, ink jet, or thermal technology
to create large-format images for architectural or
engineering uses.

32. Re vie w
• List the three most commonly used types of printers.
• List the four criteria you should consider when
evaluating printers.
• Describe how a dot matrix printer creates an image
on a page.
• Explain the process by which a laser printer
operates.
• List five types of high-quality printing devices
commonly used in business.

33.  AN ESSENTIAL COMPONENT OF EVERY COMPUTER IS ITS
MEMORY
 EACH AND EVERY WORD IS ASSIGNED AN ADDRESS IN THE
MEMORY.
 EACH WORD CONSISTS OF SAME BITS IS CALLED WORD LENGTH.
 MEMORIES CAN BE READ FROM OR WRITTEN INTO
 MEMORIES THAT CAN BE BOTH READ FROM AND WRITTEN INTO
ARE CALLED READ-WRITE MOMORIES.
 SOME MEMORIES HAVE PROGRAM OR DATA PERMANENTLY
STORED AND ARE CALLED READ ONLY MEMORY.
 THERE ARE TWO TYPES OF MEMORY DEVICE
 PRIMARY MEMORY (RAM, ROM)
 SECONDARY MEMORY (HARD DISK, FLOPPY, CD, PEN DRIVE)

34.  THERE ARE TWO TYPES OF RAM
 DYNAMIC RAM (DRAM)
 STATIC RAM(SRAM)

35.  DRAM CONSISTS OF A TRANSISTOR AND CAPACITOR.
 CAPACITOR THAT’S CAPABLE OF STORING AN ELECTRIC
CHARGE DEPENDING ON THE SWITCHING ACTION OF THE
TRANSISTOR.
 CAPACITOR EITHER CONTAIN NO CHARGE (0 BIT) OR DOES
HOLD A CHARGE (1BIT)
 DRAM PROVIDES VOLATILE STORAGE IT MEANS IF POWER
FAILURE MEANS IT WILL LOST ITS MEMORY

36.  DRAM CONTAINS TWO ELEMENTS
 MOSFET (METAL OXIDE SEMICONDUCTOR
FIELD EFFECT TRANSISTOR)
 CAPACITOR
 EACH CHIP WILL HAVE THE STORAGE
CAPACITY OF 64 BIT.

37.  THE AMOUNT OF TIME TAKEN TO
PRODUCE DATA REQUIRED FROM
MEMORY, FROM THE START OF ACCESS
UNTIL THE AVAILABLILITY OF DATA IS
CALLED MEMORY ACCESS TIME.
 DRAM CHIPS HAVE ACCESS TIME
RANGING FROM BELOW 7 TO 70
NANOSECONDS.

38.  DRAM CELL CONSISTS OF ONLY ONE
TRANSISTOR AND CAPACITOR PER BIT
 GENERALLY DRAM CHIPS ARE
AVAILABLE WITH 128 BIT OR 256 BIT
DENSITIES OR MORE

39.  THE PROBLEM OF CAPACITOR IS THAT IT
STARTS LOSING THE CHARGE OVER A
PERIOD OF TIME
 THEREFORE THE MEMORY CONTROLLER
NEEDS TO REFRESH THE MEMORY
CONTENTS AS MANY AS THOUSAND
TIMES A SECOND, WHICH IS CALLED
MEMORY REFRESHING.

40.  EDO DRAM
 Extended Data Out Dynamic Random Access
Memory, a type of DRAM that is faster than
conventional DRAM. Unlike conventional
DRAM which can only access one block of data
at a time, EDO RAM can start fetching the next
block of memory at the same time that it sends
the previous block to the CPU.
 It has a dual pipeline architecture

42.  BECAUSE OF NUMBER OF WIRES IN A SINGLE
CABLE(MULTIPLEXING) , EDO DRAM CHIPS CANNOT
OPERATE IN LOCK AND STEP INTO THEIR HOST
MICROPROCESSORS.
 THIS IS CALLED ASYNCHRONOUS MEMORY
PERFORMANCES
 THIS WILL KEEP THE MEMORY BUS SPEED LIMITED TO
66MHz.
 TO REDUCE THIS PROBLEM, IT WAS MADE POSSIBLE BY
REDESIGNING THE BASIC MEMORY CHIP INTERFACE
CALLED SYNCHRONISED DRAM
 RAMBUS DRAM
 DOUBLE DATA RATE (DDR) SDRAM

44.  THIS RAM IS FAIRLY FAST, AND IT WIL TRIED TO ADDRESS
SOME OF THE COMPLEX ELECTRICAL AND PHYSICAL
PROBLEMS INVOLVED WITH MEMORY.
 RDRAM IS NOT MULTIPLEXING, RATHER THAN IT
CREATES INDEPENDENT CONTROL.

45.  SDRAM WIL SUPPORTS ONE OPERATION IN EACH CLOCK
CYCLE,
 BUT DDR SDRAM CAN DO TWO OPERATION PER CLOCK
CYCLE
 SO THAT IT HAS DOUBLING THE MEMORY BANDWITDTH

46.  IT IS ALSO A VOLATILE BUT AS LONG AS
THEY ARE SUPPLIED WITH POWER.
 THAT MEANS IF POWER GOES MEANS IT
WILL STORE THE BINARY FORMAT OF
CONTENTS, IT WILL REMAINS TO THE
SYSTEM WHEN POWER IS APPLIED TO THE
SYSTEM.