1 Adapted from Pearson Prentice Hall Adapted from James A. Senn’s Information Technology, 3 rd Edition Chapter 4 The Central Processor and Memory

2 Adapted from Pearson Prentice Hall Objectives Describe the components and purpose of the central processing unit (CPU). Distinguish between primary storage (also called memory) and secondary storage (also called storage), and between RAM and ROM. Describe the chips and boards that can be used to augment the CPU and main memory.

3 Adapted from Pearson Prentice Hall Objectives (Continued) Explain the process by which computers use registers to process data. List and explain the four determinants of processor speed.

4 Adapted from Pearson Prentice Hall The Central Processing Unit (CPU) Definition Central Processing Unit (CPU) or Processor: The computer hardware that executes program instructions and performs the computer’s processing actions. Integrated Circuits/Chip/Microchip: A collection of thousands or millions of transistors placed on a small silicon chip.

5 Adapted from Pearson Prentice Hall The Central Processing Unit (CPU) Definition (Continued) Transistor: An electrical switch that can be in one of two states: open or closed. Integrating: The process of packing more transistors onto a single chip.

6 Adapted from Pearson Prentice Hall The Central Processing Unit (CPU) Definition (Continued)

7 Adapted from Pearson Prentice Hall The Central Processing Unit (CPU) Control Unit Control Unit: The part of the CPU that oversees and controls all computer activities according to the instructions it receives. Instructions: Detailed descriptions of the actions to be carried out during input, processing, output, storage, and transmission.

8 Adapted from Pearson Prentice Hall The Central Processing Unit (CPU) Arithmetic/Logic Unit (ALU) Arithmetic/Logic Unit (ALU): The part of the CPU that performs arithmetic and logical operations. –Arithmetic Operations: Addition, Subtraction, Multiplication, and Division. –Logical Operations: Greater Than (>), Less Than (<), Equal To (=)

9 Adapted from Pearson Prentice Hall Memory Definition Primary Storage/Primary Memory/Main Memory/Internal Memory: Storage within the computer itself. Primary memory holds data only temporarily, as the computer executes instructions.

10 Adapted from Pearson Prentice Hall Memory Definition (Continued)

11 Adapted from Pearson Prentice Hall Memory Memory Size Byte: A storage location in memory; the amount of memory required to store one digit, letter, or character. Kilobyte/K-byte/KB/K: One thousand bytes. Megabyte/M-byte/MB/Meg: One million bytes. Gigabyte/G-byte/GB/Gig: One billion bytes.

12 Adapted from Pearson Prentice Hall Memory Memory Size (Continued) Terabyte/T-byte/TB: One trillion bytes. Address: An identifiable location in memory where data are kept.

13 Adapted from Pearson Prentice Hall Memory RAM and ROM Random-access Memory (RAM): Memory that permits data or information to be written into or read from memory only as long as the computer is turned on. Read-only Memory (ROM): A type of storage that offers random access to memory and can hold data and information after the electric current to the computer has been turned off.

14 Adapted from Pearson Prentice Hall Memory Flash Memory Flash Memory: Memory that retains it contents even when electricity is turned off.

15 Adapted from Pearson Prentice Hall Memory RAM, ROM and Flash Memory EXTRA

16 Adapted from Pearson Prentice Hall Memory PCMCIA Card Memory PCMCIA Card/PC card: A card designed to expand a computer’s memory.

17 Adapted from Pearson Prentice Hall Memory Definition Boot: To turn on the computer system and let the built-in self-test run. Cold Boot: The system is turned on and started from an off state. The CPU invokes the ROM BIOS boot program, which in turn, runs the power-up self-tests and loads the operating system from disk storage. Warm Boot: In a restart, the BIOS knows the system is already running (data is written in a specific memory location checked by the BIOS) and skips the power-on test.

18 Adapted from Pearson Prentice Hall Inside the System Unit Definition Board: A hardware device onto which chips and their related circuitry are placed. System Unit: The hardware unit that houses a computer’s processor, memory chips, ports, and add-in boards.

19 Adapted from Pearson Prentice Hall Inside the System Unit Processor Chips Microprocessor: The smallest type of processor, with all of the processing capabilities of the control unit and ALU located on a single chip.

20 Adapted from Pearson Prentice Hall Inside the System Unit Evolution of Intel Pentium Family of Microprocessors

21 Adapted from Pearson Prentice Hall Inside the System Unit Intel Microprocessors Intel Celeron Processors Intel Pentium-M Processors Intel Celeron-M Processors Intel Xeon Processors Intel Itanium Processors

22 Adapted from Pearson Prentice Hall Inside the System Unit Evolution of Microprocessors for Macintosh Computers

23 Adapted from Pearson Prentice Hall Inside the System Unit Other Microprocessor Chips AMD Digital Equipment Corp. Hewlett-Packard MIPS Technologies Sun Microcomputers

24 Adapted from Pearson Prentice Hall Inside the System Unit Memory Chips Single In-line Memory Module (SIMM): A multiple-chip memory card inserted as a unit into a predesignated slot on a computer’s system board. Installed Memory: The amount of memory included by a computer’s manufacturer on its memory board. Maximum Memory: The most memory that a processor can hold.

25 Adapted from Pearson Prentice Hall Inside the System Unit Ports Port: A connector through which input/output devices can be plugged into the computer. Expansion Slot: A slot inside a computer that allows a user to add an additional circuit board.

26 Adapted from Pearson Prentice Hall Inside the System Unit Universal Serial Bus Universal Serial Bus (USB): A general purpose port that can connect numerous devices, and also hot swappable, meaning that devices can be plugged in or unplugged without having to shut down or reboot the system.

27 Adapted from Pearson Prentice Hall Inside the System Unit Add-In Boards Add-in Boards: A board that can be added to a computer to customize its features and capabilities.

28 Adapted from Pearson Prentice Hall Inside the System Unit Add-In Boards (Continued) small computer system interface

29 Adapted from Pearson Prentice Hall Inside the System Unit Plug and Play Plug and Play: The ability to install devices into a computer when the computer itself makes any necessary internal adjustments.

30 Adapted from Pearson Prentice Hall The Processing Sequence The Machine Cycle Machine Cycle: The four processing steps performed by the control unit: fetch, decode, execute, and store.

31 Adapted from Pearson Prentice Hall The Processing Sequence The Machine Cycle

32 Adapted from Pearson Prentice Hall The Processing Sequence Registers Register: A temporary storage area in the processor that can move data and instructions more quickly than main memory can, and momentarily hold the data or instructions used in processing as well as the results that are generated. Four types: –Storage Registers –Address Registers –Accumulators –General-Purpose Registers

33 Adapted from Pearson Prentice Hall Processor Speed Definition Millisecond: One thousandth of a second Microsecond: One millionth of a second. Nanosecond: One billionth of a second. Picosecond: One trillionth of a second.

34 Adapted from Pearson Prentice Hall Processor Speed Definition (Continued) Millions of Instructions per Second (MIPS): The number of instructions the processor can execute per second – a measure of processor speed. Megaflops: Millions of floating point operations per second – a measure of how many detailed arithmetic calculations the computer can perform per second.

35 Adapted from Pearson Prentice Hall Processor Speed Determining Processor Speed Four elements: –System Clock –Bus Width –Word Size –Available Memory

36 Adapted from Pearson Prentice Hall Processor Speed Determining Processor Speed (Continued) System Clock: A circuit that generates electronic impulses at a fixed rate to synchronize processing activities. –Megahertz (MHz): Millions of electric pulses per second – a measure of a computer’s speed. –Gigahertz (GHz): Billions of pulses per second.

37 Adapted from Pearson Prentice Hall Processor Speed Determining Processor Speed (Continued) Bus Width –Input/Output (I/O) bus: A bus (electronic circuit) that moves data into and out of the processor. –Data Bus: A bus that moves data between the central processor and memory. Word Size –Word: The number of bits a computer can process at one time.

38 Adapted from Pearson Prentice Hall Processor Speed Determining Processor Speed (Continued)

39 Adapted from Pearson Prentice Hall Processor Speed Determining Processor Speed (Continued) Cache Memory: A form of high-speed memory that acts as a temporary holding/processing cell. Coprocessors: A special-purpose chip mounted on a processor board; it is designed to handle common functions quickly and efficiently. Accelerator Boards: An add-in circuit board that increases a computer’s processing speed.

40 Adapted from Pearson Prentice Hall Processor Speed Determining Processor Speed (Continued) Complex Instruction Set Computing (CISC): A computing instruction set that moves data to and from main memory so often that it limits the use of registers. Reduced Instruction Set Computing (RISC): A computing instruction set that takes data for the execution of an instruction only from registers.

41 Adapted from Pearson Prentice Hall Processor Speed Determining Processor Speed (Continued) Pipelining: A computer starts processing a new instruction as soon as the previous instruction reaches its next step in the processing cycle.

42 Adapted from Pearson Prentice Hall Processor Speed Determining Processor Speed (Continued)

43 Adapted from Pearson Prentice Hall Processor Speed Determining Processor Speed (Continued) Parallel Processing: Processing in which a computer handles different parts of a problem by executing instructions simultaneously.

44 Adapted from Pearson Prentice Hall Processor Speed Determining Processor Speed (Continued)

45 Adapted from Pearson Prentice Hall Processor Speed Determining Processor Speed (Continued) Grid Computing: A process that checks idle time on computers and then uses them to provide processing for an application that needs more speed and capability than may be available on a single computer, or even on a supercomputer.