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Computer hardware

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Computer hardware

  1. 1. created by jithesh B nair systems manager people institute of management studies munnad Computer Hardware and Flow of Information
  2. 2. What is a Computer? • Computer – Device capable of performing computations and making logical decisions – Computers process data under the control of sets of instructions called computer programs – Personal computers: economical enough for individual – Distributed computing: computing distributed over networks – Client/server computing: sharing of information across computer networks between file servers and clients (personal computers)
  3. 3. What is a Computer? (cont.) • Computer Hardware –Various devices comprising a computer: –Keyboard, screen, mouse, disks, memory, CD-ROM, and processing units High-level Language Assembly Language Firmware Machine Code Hardware User Application Software OS
  4. 4. What is a Computer? (cont.) • Computer Software – Computer Programs that run on a computer, including • Operation System (OS) • Application Software • Computer Language High-level Language Assembly Language Firmware Machine Code Hardware User Application Software OS
  5. 5. Computer Architecture A Typical Von-Neumann Architecture Example: 1. Input unit 2. Output unit 3. Memory unit 4. Arithmetic and logic unit (ALU) 5. Central processing unit (CPU) 6. Secondary storage unit Control Circuit (ex: PC: Program Counter) ALU Memory I/O CPU
  6. 6. Computer Architecture (cont.) Five major operations performed by a computer system: 1. Input • Obtains information from input devices (keyboard, mouse) 1. Storage • Primary o or main memory or internal memory / memory o the only one directly accessible to the CPU. o The CPU continuously reads instructions stored there and executes them as required. o Eg: ROM (Read Only Memory): CMOS, EPROM o RAM (Random Access Memory): SRAM, DRAM, SIMM, DIMM • Secondary o known as external memory or auxiliary storage o Not directly accessible by the CPU o Eg: Hard disk, flash memory, floppy disks
  7. 7. Computer Architecture (cont.) Six logical units in every computer (cont): 3. Processing 4. Output • Outputs information (to screen, to printer, to control other devices 3. Control
  8. 8. Computer Architecture (cont.) Basic computer functional units control • Arithmetic and logic unit (ALU) – part of CPU  Performs arithmetic calculations (addition, subtraction...) and logic decisions • Control unit (CU) - part of CPU  Supervises and coordinates the other sections of the computer
  9. 9. Computer Architecture (cont.) • Central Processing Unit (CPU) – “brain” of a computer, consisting of • Arithmetic and logic unit (ALU): performs arithmetic calculations (addition, subtraction...) and logic decisions (>, <, =, ...) • Control Unit (CU): decodes each machine instruction and sends signal to other components for carrying out the instruction. – An integrated circuit (IC) that is a full central processing unit is called a microprocessor (µp); a CPU’s current instruction and data values are stored temporally inside the CPU in special high-speed memory location called registers. – CPU speed: ? MHz (M: Mega = 106 , Hz=1/sec);
  10. 10. Computer Architecture (cont.) • Memory – A large collection of circuits, each capable of storing bit – Cells (words): manageable units; typical size is 8 bits (1 byte), some machines are 16 bits (2 bytes) and some are 32 bits or 64 bits • Byte (8 bits), KB (kilobyte, 103 ≈ 210 bytes), MB (Megabyte, 106 ≈ 220 bytes), GB (Gigabyte, 109 ≈ 230 bytes). Note: k ≠ K because 1000 ≠ 1024.
  11. 11. Computer Architecture (cont.) – Computer memory is comparable to a collection of numbered mailboxes. To identify individual cells in a machine’s main memory, each cell is assigned a unique name, called its address – The organization of byte-size memory cell ...01001000 01100101 01101100 0110111101101100 00101110 H e l l o ,ASCII ...Data Address 0000 0101 0000 0110 0000 0111 0000 1000 0001 0001 0001 0010 Address Bus Data Bus 0 0 0 0 0 1 0 1 Low-order endHigh-order end Least Significant Bit (LSB)Most Significant Bit (MSB)
  12. 12. A Typical Von-Neumann Architecture Example: 1. Input unit 2. Output unit 3. Memory unit 4. Arithmetic and logic unit (ALU) 5. Central processing unit (CPU) 6. Secondary storage unit Control Circuit (ex: PC: Program Counter) ALU Memory I/O CPU
  13. 13. Computer’s Bus System • A bus, in computing, is a set of physical connections (cables, printed circuits, etc.) which can be shared by multiple hardware components in order to communicate with one another. • think of a bus as a highway on which data travels within a computer.
  14. 14. Computer’s Bus System (cont..) • Purpose of buses = to reduce the number of "pathways" needed for communication between the components, by carrying out all communications over a single data channel.
  15. 15. Types of Computer’s Bus • There are generally two buses within a computer: • Internal bus (system bus) – Allows the processor to communicate with the system's central memory (the RAM). • External bus (expansion bus) – Allows various motherboard components (USB, serial, and parallel ports, cards inserted in PCI connectors, hard drives, CD- ROM and CD-RW drives, etc.) to communicate with one another. – However, it is mainly used to add new devices using what are called expansion slots connected to the input/output bus.
  16. 16. Types of External Buses • There are five major types of external bus’s found on the common motherboard. – ISA (Industry Standard Architecture) • This bus is the low speed work horse of the system. • commonly find a Sound Card hooked up this type BUS. – PCI (Peripheral Component Interconnect) • Supports 32-64 bit bus and is the reigning standard of external buses. • Fast • slowly making the ISA fade away. Go with a PCI Bus Card when possible.
  17. 17. Types of External Buses (cont…) – AGP (Accelerated Graphics Port) • This Bus provides from 2 to 4 times the speed of the PCI • used for video expansion only. • great way to go and takes a lot of stress off the CPU, thus gaining in performance all the way around. – USB (Universal Serial Bus) • allows to hook up to 127 devices. • probably going to wipe out PS/2 ports and more. • Allows to hot swap devices or plug and unplug devices while system is running. • a great feature and is incorporated on most new motherboards.
  18. 18. Types of External Buses (cont…) – IDE (Intelligent Drive Electronics) • used mostly for disk drives • connects up to two devices on one connection. • More than likely hard drive and CD-ROM are connected through this type bus.
  19. 19. Operation of bus protocol • PCI • SCSI
  20. 20. THANK YOU • WAIT FOR MOR PRESENTATIONS

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