2. The Computer System

2.1 System Unit

Classification of Computers

• Mainframe– Most intensive computational tasks– Large, powerful and expensive– Can handle large centralised database and

run many applications at the same time– Designed for multi-user environment– Often used in government departments or l

arge organisations.

Picture is captured from ibm.com

Classification of Computers

• Mainframe

Picture are captured from Computer Studies for the New Generation Vol. 1, W.H. Kwan, Chung Tai Educational Press

Classification of Computers

• Minicomputer

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MicroComputer Set

• Desktop / Personal Computer (PC)

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MicroComputer Set

• Laptop / Notebook

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MicroComputer Set

• Workstation

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MicroComputer Set

• Handheld / Palmtop

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Hardware Components

• Hardware are the physical components of a computer system. These components can be divided into five groups:– Input device– Output device– CPU– Main memory– Storage device

Hardware Components

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Input Device

CPU

Output Device

Main Memory

Storage Device

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CPU

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• CPU (central processing unit) is an older term for processor and microprocessor, the central unit in a computer containing the logic circuitry that performs the instructions of a computer's programs

• CPU is the "brain" of the computer. Its function is to execute programs stored in the main memory by fetching their instructions, examining them, and then executing them one after another.

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CPU

• The processor (really a short form for microprocessor and also often called the CPU or central processing unit) is the central component of the PC. It is the brain that runs the show inside the PC. All work that you do on your computer is performed directly or indirectly by the processor.

* Copied from pcguide.com

CPU

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CPU

• Reference sites:– http://www.pcguide.com/ref/cpu– http://einstein.et.tudelft.nl/~offerman/– http://www.webopaedia.com– http://www.whatis.com – http://www.sharkyextreme.com/hardware/h

ardware_cpu.shtml– http://www.soyo.com.tw/

* Copied from pcguide.com

CPU

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• The processor controls the entire PC, and uses dedicated control pathways called "buses" to send information between itself and the system cache, memory and other devices. These are the processor's external interfaces, which can be different even for otherwise similar CPUs.

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CPU

• Older CPU consists of– Arithmetic Logic Unit (ALU)

• Perform arithmetic on data. E.g., +, -, ×, ÷• Perform logical operations on data. E.g. testing whether 2

data items are equal (true or false)

– Control Unit• Control the access of data and instructions from main

memory (extracts instructions from memory and decodes and executes them, calling on the ALU when necessary)

• Direct the sequence of instructions• Interpret each program instruction (decode instructions)• Give control signals (or commands) to appropriate

hardware devices

CPU

• Older CPU consists of– Bus Interface

• Under the monitoring of control unit, read/write data and communicate with other PC components through Bus.

CPU

• Modern CPU consists of– Arithmetic Logic Unit (ALU)

• Perform arithmetic and logical calculation• Can simultaneously execute many operations with a number of i

ndividual ALU

– Execution Control Unit• Coordinate the operations of other units

– Floating Processing Unit (FPU)• Perform floating point calcuation

– Instruction Decoder• Decode instructions• Extracts instructions from memory and decodes and executes t

hem

CPU

• Modern CPU consists of– Bus Interface

• Under the monitoring of control unit, read/write data and communicate with other PC components through Bus.

– Cache• A special high-speed storage mechanism.• Reduce the number of times of the direct

access between CPU and main memory• Improve the efficiency of the CPU operations

CPU

• Efficiency of CPU based on– A. Bit processing capability

• Registers• Data bus• Execution width of instructions• Unit is bit

CPU

• Efficiency of CPU based on– B. Memory Control

• Number of address lines• E.g. 32 address lines can control 232 Bytes = 4

GB

– C. Structure of Internal Operation• Cache, data read/write, instruction read/write,

memory read/write, …

CPU

• Efficiency of CPU based on– D. Chips’ circuit size ( 晶片製程 )

• The size of MOS (metal-oxide semiconductor) transistor• The smaller the circuit size, the more of MOS transistors c

an be packed inside a chip, and thus the more powerful is the processor.

• 3 kinds: TTL, CMOS, BiCMOS• CPUs employ CMOS and BiCMOS• Unit is micron / μm = 10-6 m• Microns is the width, in microns, of the smallest wire on th

e chip. For comparison, a human hair is 100 microns thick. As the feature size on the chip goes down, the number of transistors rises.

CPU

• Efficiency of CPU based on– E. Clock

• The higher the clock speed, the shorter the time a CPU requires to execute an instruction, thus the higher the overall efficiency.

• Unit is MHz (Mega Hertz)

• References:– http://www.pcguide.com/ref/cpu/char/chip.htm– http://einstein.et.tudelft.nl/~offerman/cl.2.1.html

Some Types of CPUs

AMD Duron 950 MHz AMD Athlon 1.4 GHz

AMD

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Some Types of CPUs

Celeron 800 MHz

Pentium !!! 1 GHz

Intel

                       

        

P4 2.0 GHz

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Some Types of CPUs

• Reference– http://www.sharkyextreme.com/hardware/h

ardware_cpu.shtml

Socket Standards

• Socket 7– 321-pin square-sized PGA

ZIP socket– Highest clock rate is 66 M

Hz– AMD processors, Cyrix M-

II, IDT WinChip 2

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Socket Standards

• Socket 7– Zero Insertion Force (ZIP) socket is a type

of socket designed for easy insertion of pin grid array (PGA) chips. The chip is easily dropped into the socket's holes, and a lever is pulled down to lock it in. Pulling the lever moves the top plate of the assembly, pushing the pins into their contacts.

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Socket Standards

• Socket 370– Socket 370 is Intel's new plasti

c PGA (PPGA) ZIF motherboard socket for its line of Celeron and Pentium processors.

– more economical than the elaborate Slot 1 Pentium II system

– Socket 370 accepts a 370-pin PPGA chip package, instead of the SEC (single edge cartridge) Slot 1 package.

Copied from techweb.com/encyclopedia/ and webopaedia.com, soyo.com.tw and (tomshardware.com)

Socket Standards

• Socket 370 – http://www.overclocker.com.tw/99/

socket370.asp

Socket Standards

• Socket 8– A receptacle on the mothe

rboard for a K7 CPU chip from AMD. It is physically similar to Slot 1, but has different electrical requirements

• Socket A– Designed for some AMD A

thlon and Duron CPUs

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Socket A

Socket Standards

• Socket 423 and socket 478– Designed for P4 CPUs

• Super7– A specification from AMD for PC motherboards

or single board computers that allows non-Intel CPU chips to take advantage of faster bus speeds and newer peripheral technologies. It specifies the older Socket 7 CPU receptacle and adds support for AGP, USB, Ultra ATA and the 100MHz bus

Slot Standards

• Slot 1– A 242-pin slot on the

motherboard that holds Intel CPU modules including the Intel Single Edge Contact Cartridge (SECC and SECC2) and Single Edge Processor Package (SEPP).

– Slot 1 is a narrow slot like a PCI bus slot

– P2 was the first to use Slot 1

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Slot Standards• Slot 2

– A 330-pin slot – Intel's Xeon chips were the first to use Slot 2– Designed for multiprocessing (SMP) systems, Slot 2 m

otherboards typically come with two slots and require a termination card if only one CPU is plugged in

– The biggest difference between Slot 1 and Slot 2, though, is that the Slot 2 design allows the CPU to communicate with the L2 cache at the CPU's full clock speed. In contrast, Slot 1 only supports communication between the L2 cache and CPU at half the CPU's clock speed.

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Slot Standards

• Slot 2

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Slot Standards

• Slot A– A receptacle on the

motherboard for a K7 CPU chip from AMD. It is physically similar to Slot 1, but has different electrical requirements

Copied from techweb.com/encyclopedia/ and soyo.com.tw

CPU Speed

CPU speed ( 內頻 )

= External clock ( 外頻 ) × Multiplier factor ( 倍頻 )

• External clock (Local Bus rate) is the working speed of the devices on the motherboard

CPU Speed

• Setting the working frequency higher than the PCI chipset or processor specs, may cause abnormal memory module functioning, system hangs, hard disk drive data lose, abnormal functioning of the VGA card, or abnormal functioning with other add-on cards

CPU Clock• Using a quartz crystal, the

CPU clock breathes life into the CPU by feeding it a constant flow of pulses.

• For example, a 200MHz CPU receives 200 million pulses per second.

• Similarly, in a communications device, the clock synchronizes the data pulses between sender and receiver.

Working Voltage• Each CPU has its own working voltage• Normally, the higher the voltage, the larger the work

done, and thus CPU may hang due to the higher the temperature

• The lower the voltage, the less the electricity consumption, the lower the CPU’s temperature

• Common CPUs have double-voltage design– Vcore ( 核心電壓 ) and Vio ( 對外電壓 )

• P2, P!!! and Celeron CPUs directly send a set of Voltage Identification (VID) signals to the power supply on the motherboard

How to Install CPU

• Reference:– http://www.sharkyextreme.com/hardware/

guides/cpu_install_guide/