Presentation is loading. Please wait.

Presentation is loading. Please wait.

Reference Text : Computer Fundamentals by Anita Goel

Similar presentations


Presentation on theme: "Reference Text : Computer Fundamentals by Anita Goel"— Presentation transcript:

1 Reference Text : Computer Fundamentals by Anita Goel
Module 1 Reference Text : Computer Fundamentals by Anita Goel

2 Syllabus Introduction to digital computer – Von Newman concept – A simple model of computer with acquisition of data, storage of data, processing of data, output of processed data. Details of functional units of a computer. Storage – primary storage and secondary storage. Introduction to programming languages: types of programming languages - high level language , assembly language and machine language System software - Operating systems – objectives of operating systems, compiler, assembler and interpreter.

3 Computer 2 Types Digital Computers : Analog Computers :
uses distinct value to represent data internally. Informations are represented using 0 and 1 Analog Computers : represents data as variables used to process analog data. Analog data is of continuous nature and which is not discrete or separate. temperature, pressure, speed weight, voltage, depth etc.

4 Digital Computers Von Neumann Concept
  a computer architecture in 1945 by the mathematician and physicist John von Neumann electronic digital computer with parts consisting of processing unit containing an arithmetic logic unit and processor registers a control unit  a memory to store both data and instructions, external mass storage  input and output units.  stored-program computer  Bottleneck : - an instruction fetch and a data operation cannot occur at the same time because they share a common bus.

5

6 Central Processing Unit
Brain of the computer Consists of ALU , Control Unit (CU) , registers and instructions Executes stored program program instruction Data and instructions are stored in memory before execution CPU gets data and instruction from memory, interprets the program instructions and perform the required arithmetic and logic operations

7 Control Unit Arithmetic Logic Unit
Central Processing Unit Control Unit Arithmetic Logic Unit Registers

8 Arithmetic Logic Unit Consists 2 units Arithmetic unit Logic unit
Performs arithmetic operations on data Ex: addition,subtraction ,multiplication etc Performs logic operations on data Ex: comparison of numbers,letters and special characters. Uses registers to to hold data that is being processes.

9 Registers High speed storage area within CPU Least storage capacity
Directly accessed by CPU Refers as CPU’s working memory Used to store data,instructions,addresses and intermediate results.

10 PC IR MAR ACC MBR DR

11 Important registers are
Accumulator ACC : Stores results of arithmetic and logic operations Instruction register IR : contains current instruction most recently fetched Program Counter PC : contains the address of the next instruction is to be fetched Memory Address Register MAR : address of next location in the memory to be accessed Memory Buffer Register MBR: temporary stores data from memory or data to be sent to memory Data Register DR : stores the operands and any other data.

12 Word size : - size of register, indicates the amount of data with which computer can work at any given time. May be in 8,16,32,64 bits

13 Control Unit Organizing the processing of data and instructions
Act as a supervisor, controls and coordinates the activities of other units of computer. Directs the computer to carry out stored program instruction by communicating with ALU and the registers. Uses IR to decide which circuit to be activated. Instructs the ALU to perform the operation CU tells when to fetch the data and instruction,what to do and where to store the program

14 Memory Unit Consists of Cache memory Primary memory Secondary memory
RAM ROM Secondary memory

15 Cache Memory It is a storage buffer that stores the data that is used more often, temporarily and makes them available to CPU at fast rate. Very high speed memory placed between RAM and CPU Increases the speed of processing. During processing ,CPU first checks cache for data,if not then CPU looks in the RAM for data. No system bus for accessing the cache.

16 CPU has built in Level1 (L1) cache and Level2(L2) cache.
L3 Cache – cache on the motherboard. Intel core i7 L KB L2-6MB L3-12MB Very expensive Small in size

17

18 Primary Memory Main memory of computer
Used to store data and instructions Semiconductor memory Provides a limited storage capacity – high cost 2 kinds RAM ROM Non volatile memory Permanent Store std processing programs Programmed by manufacturer

19 Interaction of CPU with memory

20 Secondary Memory Stores data and instructions permanently
Non volatile memory Provides back up storage High storage capacity Cheaper Takes longer time to access the data and instructions . Hard disk, CD, Floppy disk.

21 Instruction Format Describes the steps to be performed for carrying out a computational task. A computer program is a set of instruction Fields – instruction is divided into groups The common fields are Operation code – action that the processor must execute Opcode-parameters of the action(location or operands)

22 Instruction format Example : ADD command

23 INSTRUCTION SET Set of instructions that the processor understands
Set of all basic operations that a processor can accomplish. Language that the processor understand EX : ADD A,B MOV B,A RAR

24 INSTRUCTION CYCLE The series of steps for executing an instruction by CPU. 4 steps Fetching Decoding Executing Storing

25

26 4 type of instructions Memory access or transfer of data between registers Mov B,A Arithmetic instructions Add B Logic instructions AND,OR Control and conditional instructions JMP,JC

27

28 BUS Set of electronic signal pathways that allows information to travel between components inside or outside of a computer. 2 types Internal (System Bus) External Bus(Expansion bus)

29 External Bus Connects different external devices , peripheral , expansion slots and I/O ports to the rest of computers Allows expansion of computer’s capability Slower than internal bus(System Bus) Also referred as expansion bus

30 3 kinds Data bus – used to transfer data between I/O devices and CPU
EISA PCI AGP USB Address Bus – Carries the address of different I/O device to be accessed Control Bus – used to carry read/write commands,status of I/O devices etc.

31 Microprocessor an integrated circuit that contains all the functions of a central processing unit of a computer. Classified into two RISC – Reduced Instruction Set Computer CISC – Complex Instruction set Computer

32

33 CISC has a large instruction set that includes simple and fast instructions for performing basic tasks, as well as complex instructions that correspond to statements in the high level language. An increased number o f instructions (200 to 300) results in a much more complex processor, requiring millions o f transistors. Instructions are o f variable lengths, using 8, 16 or 32 bits for storage. AMD based on CISC.

34 RISC RISC has fewer instructions and requires fewer transistors
manufacturing cost of processor is less The instruction size is fixed (32 bits). speeds up the program execution when compared to CISC processors. RISC processors can handle multiple instructions simultaneously by processing them in parallel. Apple Mac G3 and PowerPC are based on RISC.

35 Athalon XP and P IV - Hybrid

36 Memory Storage area used to store data,instructions and intermediate results. Binary digits or bits – unit of memory 0 or 1 - one bit Byte - group of 8 bits Word – a group of bytes (2,4,or 8 bytes)

37 Memory Hierarchy Characterized on the basis of
Capacity – the amount of information that the memory can store Access time – time interval between read/write request and the availability of data Memory with fastest speed and largest capacity

38

39 Catagories Internal External Used by CPU to perform task Ex..
Used to store the large amount of data and the software Also known as secondary memory

40 Internal Memory -Features
Limited storage capacity Temporary storage Fast access High cost Registers, primary memory and cache memory

41 External Memory Very high storage capacity Permanent storage
Slower access Stores data and instructions that are not currently accessed by CPU Cheapest

42 Memory organization With respect to CPU
Registers are placed inside the CPU Cache memory is placed next in the hierarchy Primary memory is placed next in the lab Secondary memory is the farthest from CPU

43 Primary Memory RAM DRAM SRAM ROM PROM EPROM EEPROM

44 RAM Random Access memory
Used to store data & instructions during the operation of computer CPU interacts with RAM for processing Volatile memory Provides random access to the stored data Read from and written to with the same speed Size is small Cost is high

45 2 kinds DRAM SRAM

46 DRAM Dynamic RAM Common type of memory Used as main memory
Small and cheap Uses transistors and capacitors Memory cell – pair of transistor and capacitor Transistor act as switch Capacitor holds information as bits Memory controller is used – refreshment of storage Access speed -50 to 150 ns

47 SRAM Static RAM Used as cache memory High speed
Uses multiple transisitors(4 to 6) for each memory cell Doesn’t have capacitor in each cell No constant refreshing More expensive Stores information as long as it is supplied with power Easy to use and very fast Access speed – 2-10 ns

48 Memory Module PCB – Printed Circuit Board SIMM – DIMM
chip on one side of the PCB Can store 8 to 32 bit simultaneously DIMM Memory chip on both side of the PCB 64 bit SODIMM for portable computers-32 bit

49 ROM Non volatile primary memory
Does not lose its content when the power is switched off. Has only read capability and no write capabilty Programmed by manufacturer stores BIOS

50 BIOS information required to boot system Permanent part of computer
Provides the resources available in the system BIOD does POST - program that runs automatically when system is booted and checks that the major hardware components are work properly BIOS setup Program – built in utility ,lets the user to set many functions to control how the computer works. Also initialize registers and loads device drivers Bootstrap Loader

51 Bootstrap Loader It is program to start the computer software for operation when the power is turned on. Loads the OS into RAM and launches it Resides in the ROM

52 3 types of ROM PROM EPROM EEPROM

53 PROM Programmed with special tools Contents cannot be changed
Thousands of diodes

54 EPROM Programmed by special tools
Can be erased by exposing it to UV light and reprogrammed Have to be removed from computer for rewriting

55 EEPROM Can be erased by electric charges and reprogrammed
Do not have to removed from computer for rewriting

56 Flash Memory Special type of EEPROM Combines features of RAM and ROM
Random access memory Data is not lost High speed memory,durable and low energy consumption Used in mobile phones,camera,laptop etc

57

58 Secondary Memory Magnetic tape drives Magnetic Disk Optical Disk
Floppy Hard disk Zip Disk Optical Disk CD ROM DVD ROM Recordable optical disk Magneto optical disk

59 Access types Sequential Direct Access Magnetic tapes Magnetic disk
Optical Disk Magneto –optical disk

60 Magnetic tapes It is a plastic tape with magnetic coating Cheaper
Durable , written , erased and rewritten Sequential Access Not suitable for data files that need to be updated often Used to store data that are not frequently used

61 Features Inexpensive Store large amount of data Easy to carry
Not suitable foe random access Slow access device Need dust prevention, as dust can harm the tape A 10 inch diameter reel of tape can store upto 180 million characters.

62 Working Tape is divided horizontally into tracks and vertically into frames Frame stores 1 byte of data and tracks in a frame stores 1 bit. Data are stored in successive frames as a string with one data per frame. Data is recorded on tape in the form of blocks Record – group of data(block) Each block read continually

63 Tape is mounted on magnetic tape drive for access. Drive mechanism
IRG – inter record gap Provides time for the tape to be stopped and started between records Tape is mounted on magnetic tape drive for access. Drive mechanism Consisit of supply reel, take-up reel and read/write head The tape is moves on the drive from supply reel to take-up reel, with its magnetic coated side passing over the read/write head.

64

65 How do you read data from it?
The purpose of any magnetic tape unit is to write data on and read data from the tape used by the device. Tape is moved from a supply reel or hub to a take-up reel or hub on the magnetic tape transport section of the unit The magnetic oxide coated side of the tape passes in close proximity of  a read/write

66 Magnetic Disk It is a thin plastic or metallic circular plate coated with magnetic oxide Presence of magnetic tape – bit 1 Absence - bit 0

67 Features Cheap Can store a large amount o f data
Easy to carry or transport Suitable for frequently read/write data Fast access device More reliable storage device To be prevented from dust, as the read/write head flies over the disk.

68 Working Tracks – the surface of disk is divided into concentric circles The outermost track is numbered 0 and innermost track is the last one Sector –division of tracks,it is a pie slice that cuts across all tracks The data on disk is stored in sector

69

70 Magnetic disk is inserted into a magnetic disk drive for access
Magnetic disk is inserted into a magnetic disk drive for access. The drive consists of a read/write head that is attached to a disk arm, which moves the head. The disk arm can move inward and outward on the disk. Storage capacity is measured in gigabytes(GB) Double sided disk –tracks and sectors on both sides Cylinder – set of same tracks on all disk.

71 Accessing data on the disk requires the following
The time taken to move the read/write head to the desired track is called the seek time. • Once the read/write head is at the right track, then the head waits for right sector to come under it (disk is moving at high speed). The time taken for desired sector o f the track to come under read/write head is called the latency time. Once the read/write head is positioned at the right track and sector, the data has to be written to disk or read from disk. The rate at which data is written to disk or read from disk is called data transfer rate. The sum o f seek time, latency time and time for data transfer is the access time o f the disk.

72 Floppy Disk is a flat, round, single disk made o f Mylar plastic and enclosed in square plastic jacket Floppy Disk Drive (FDD) is the disk drive for floppy disk write-protcct slide tab that prevents a user from writing to it.

73 may be single-sided or double-sided disk
Portable small and inexpensive slower to access than hard disk less storage capacity and are less expensive than hard disk.

74

75 Hard Disk consists o f one or more platters divided into concentric tracks and sectors mounted on a central spindle, like a stack. can be read by a read/write head The data is stored on the platters covered with magnetic coating.

76

77 Hard disk is a fixed disk. The disk is not removable from the drive
The hard disk and Hard Disk Drive (HDD) is a single unit. The data can store on both sides o f each platter the read/write head o f hard disk does not touch the disk during accessing. can store up to 500 GB o f data

78 Zip Disk high-capacity removable disk and drive.
have the speed and capacity o f hard disk and portability o f floppy disk. Zip disk are o f the same size as floppy disk comes as a complete unit—disk, drive, connection cable, power cord and operating system. It can be connected to the computer system externally using a parallel chord or SCSI cable. capacity ranges from 100 MB to 750 MB. used to store large files, audio and video data.

79

80 Optical Disk Flat and circular disc
Coated with reflective plastic material Can be altered by laser lights Can store large amount of data in a small space Access time : 100 ns to 200ns 2 catagories Read only Recordable

81 Sectors and track in magnetic disk and optical disk

82 CD ROM Medium for storing music Can only be read and not written to
Cost is low Access time is less Data are stored as pits and lands on disk. When laser light is focused on the disk, the pits scatter the light and the lands reflect the light to a sensor.

83 DVD ROM Digital Video Disk Read only memory
Store digital video or computer data Improves on CD technology Uses both sides of disk

84 Recordable optical Disk
CD-R – write once read many CD-RW data can be written, erased and re written DVD-R Allows recording of data

85 Magneto optical device
Use laser beams to read and magnetic field to write data to disk data can be written, erased and re written Expensive Outdated

86

87 I/O Ports The external interface used to connect i/o devices
The different port are Parallel port Serial port USB port Firewire

88 Parallel Port An interface for connecting 8 or more data wires
Transmits 8 bits of data parallel. Provides high speed data transmission Eg: Used to connect printers

89 Serial Port Transmits 1 bit of data through a single wire
Slow speed data transmission Used to connect modem , barcode reader etc.

90 USB Port Allows different devices to be connected to computers without requiring rebooting Plug and play

91 Firewire Used to connect audio and video multimedia device like video camera Expensive Used for large data movement Connect HDD and DVD drive

92 MIDI Musical Instrument Digital Interface

93 Operating System software that controls and coordinates the use of hardware among different sofs and users. Intermediate between the user and computer hardware

94 Objectives To make the computer system convenient and easy to use
To use the computer hardware in an efficient way by handling the details of the operations of the hardware.

95 Functions of OS Process management Memory management File management
Device management Protection Security User interface

96 Process management Control access to shared resources
Control the execution of program Create, execute and delete a process Cancel or resume a process Synchronization and communication of processes

97 Memory Management Allocate memory Free memory Re allocate memory
Keep a track of memory usage

98 File management Create and delete both files and directorirs
Provide access to files Allocate space for files Keep backup of files Secure files

99 Device Management Open, close and write device drivers
Communicate, control and monitor the device driver

100 Protection Security Protects the resources of system
Provides security mechanisms Prevents unauthorized access to computer

101 User interface Provides an Interface between the user and computer hardware Interface is a set of commands which the user interacts with the application and the hardware.


Download ppt "Reference Text : Computer Fundamentals by Anita Goel"

Similar presentations


Ads by Google