1. The Central Processor and Memory
Chapter 4
The Central Processor
and Memory

2. The Central Processing Unit (CPU) Definition
Central Processing Unit (CPU) or Processor:
executes program instructions and
performs the computer’s processing actions.
Integrated Circuits/Chip/Microchip:
thousands or millions of transistors
placed on a small silicon chip.

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

4. The Central Processing Unit (CPU) Definition (Continued)

5. The Central Processing Unit (CPU) Control Unit
The part of the CPU
oversees and controls all computer activities
Instructions:
Low level actions to be carried out during
input
processing
output
storage
transmission.

6. The Central Processing Unit (CPU) Arithmetic/Logic Unit (ALU)
part of the CPU
performs arithmetic and logical operations.
Logical Operations:
Greater Than (>)
Less Than (<)
Equal To (=)
Arithmetic Operations:
Addition
Subtraction
Multiplication
Division.

7. Memory Definition Primary Storage Primary Memory Main Memory
Internal Memory
RAM:
Primary memory holds data temporarily,
as the computer executes instructions.

8. Memory Definition (Continued)

9. Memory Memory Size Bit: On or Off 1 or 0 2 Bits:
Four different values: 00, 01, 10, 11
3 Bits:
Eight different values:
000, 001, 010, 011, 100, 101, 110, 111
Byte:
8 bits
256 different values
Approximately 200 printable characters.

10. Memory Memory Size Kilobyte (KB or K): 1000 bytes
500 word text file  about 3-4K
Megabyte (MB):
One million bytes.
Bitmap 800 X 600 X 24 bits  1.4 MB
Gigabyte (GB):
One billion bytes.
Terabyte (TB):
One trillion bytes.

11. Memory Memory Size (Continued)
How much space?
Turing
1,000 home directories
average home directory size 250 MB
Image
2400 X 1800 resolution
64,000 colors
Database
500,000 people
first name
last name
phone number

12. Memory RAM and ROM ROM Read-only Memory
Memory is persistent even if computer is turned off
Computer BIOS is stored on ROM chip
BIOS (Basic Input Output System) need so computer can boot
RAM
Random-access Memory
Read or Write
Memory is lost when computer is turned off
Random-access  any part of the memory can be access in constant time.

13. Memory Flash Memory Flash Memory: Read and Write
retains it contents even when electricity is turned off.
Currently used in
Cell phones
Digital Cameras
iPods, MP3 players
Key chains

14. Memory RAM, ROM and Flash Memory

15. Memory Definition Boot: To turn on the computer system
let the built-in self-test run.
Cold Boot:
turned on from an off state
CPU invokes the ROM BIOS boot program, which 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.

16. Inside the System Unit Definition
Board:
A hardware device onto which chips and their related circuitry are placed.
System Board (Mother Board):
The hardware unit that houses a computer’s processor, memory chips, ports, and add-in boards.

17. 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.

18. Inside the System Unit Evolution of Intel Pentium Family of Microprocessors

19. Inside the System Unit Intel Microprocessors
Intel Celeron Processors
Does NOT have L2 cache, i.e., expensive memory that speeds up performance
Intel Pentium Processors
The Standard
Intel Xeon Processors
Designed to work in pairs (dual processors)
Intel Itanium Processors
64-bit processor

20. Inside the System Unit Evolution of Microprocessors for Macintosh Computers

21. Inside the System Unit Other Microprocessor Chips
AMD
Digital Equipment Corp.
Motorola
MIPS Technologies
Sun Microcomputers

22. 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.

23. Inside the System Unit Ports
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.

24. Inside the System Unit Universal Serial Bus
Universal Serial Bus (USB):
A general purpose port that can connect up to 128 devices, and also hot swappable,
meaning that devices can be plugged in or unplugged without having to shut down or reboot the system.

25. Inside the System Unit Add-In Boards
A board that can be added to a computer to customize its features and capabilities.

27. Inside the System Unit Plug and Play
The ability to install devices into a computer when the computer itself makes any necessary internal adjustments.

28. The Processing Sequence The Machine Cycle
The four processing steps: fetch, decode, execute, and store.
Instruction Cycle (I-cycle):
The first two steps (fetch and decode), in which instructions are obtained and translated.
Execution Cycle (E-cycle):
The last two steps of the machine cycle (execute and store), which produce processing results.

29. The Processing Sequence The Machine Cycle

30. The Processing Sequence Registers
temporary storage built into the processor
can move data and instructions more quickly than main memory can
Four types:
Storage Registers
Address Registers
Accumulators
General-Purpose Registers

31. 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.

32. 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.

33. Processor Speed Determining Processor Speed
Four elements:
System Clock
Bus Width
Word Size
Available Memory

34. 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 electric pulses per second.

35. 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.

36. Processor Speed Determining Processor Speed (Continued)

37. 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

38. Processor Speed Determining Processor Speed (Continued)
CISC:
Complex Instruction Set Computing
Intended to be an improvement
Complex instructions require main memory
RISC:
Reduced Instruction Set Computing
A return to the old way
Compact instructions need only registers

39. 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.

40. Processor Speed Determining Processor Speed (Continued)

41. Processor Speed Determining Processor Speed (Continued)
Sequential Processing:
Processing in which the execution of one instruction is followed by the execution of another.
Parallel Processing:
For computers will multiple processor
computer handles different parts of a program by executing instructions simultaneously.

42. Processor Speed Determining Processor Speed (Continued)
SIMD
Single Instruction/Multiple Data method
A parallel-processing method
executes the same instruction on many data values simultaneously.
MIMD
Multiple Instruction/Multiple Data method
connects a number of processors that run different programs or parts of a program on different sets of data.

44. Processor Speed Determining Processor Speed (Continued)
Grid Computing:
A process that harnesses idle time on a computer
uses multiple computers to provide processing for an application that needs more speed and capability