Kategorier: Alle - coding - memory - data - machine

af Maad Maad 11 år siden

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chapter 2: system unit: processing and memory.

The chapter delves into the core components of a computer system, focusing on processing and memory. It emphasizes the importance of coding systems in representing data and software programs in a format that computers can understand.

chapter 2: system unit: processing and memory.

chapter 2: system unit: processing and memory.

very impressive. nice collection of resources here. But, reorganize so you can link this ch. 2 to your main topic, 'Maad's CSC 101 Knowledge Base'.

Please put your name in the main topic

HOW THE CPU WORKS

"The key element of the processor is the transistor"

"the transister is a device made of semiconductor material that controls the flow of electrons inside a chip."

The System Clock and the Machine Cycle

System clock. The timing mechanism within the computer system that synchronizes the computer’s operations.

Machine cycle. The series of operations involved in the execution of a single machine level instruction.

1. Fetch—the program instruction is fetched.

2. Decode—the instructions are decoded so the

control unit, ALU, and FPU can understand them.

3. Execute—the instructions are carried out.

4. Store—the original data or the result from the ALU

or FPU execution is stored in the CPU’s registers.

Typical CPU Components

The architecture and components included in a CPU (referred to as microarchitecture) vary from processor

to processor.

Bus Interface Unit

Bus Interface Unit: The part of a CPU core that allows it to communicate with other CPU components.

Registers and Internal Cache Memory

Registers are groups of high-speed memory located within the CPU that are used

during processing.

Decode Unit

Decode Unit: The part of a CPU core that translates instructions into a form that can be processed by the ALU and FPU.

Prefetch Unit

Prefetch unit: The part of a CPU core that attempts to retrieve data and instructions before they are needed for processing in order to avoid delays.

Control Unit

"The control unit coordinates and controls the operations and activities taking place within

a CPU core"

Arithmetic/Logic Unit (ALU) and Floating Point Unit (FPU)

is the section of a CPU core that performs arithmetic involving integers and logical operations

-Floating point unit (FPU).The part of a CPU core that performs decimal arithmetic.

MAKING COMPUTERS FASTER AND BETTER NOW AND IN THE FUTURE

There are several ways computer users can speed up their existing computers today.

Future Trends

Selected trends we will

likely see more of in the near future are discussed next.

Silicon Photonics

Silicon photonics refers to the process of sending optical information among computers

and other electronic devices using standard silicon manufacturing techniques

Optical Computing

A computer that uses light, such as from laser beams or infrared beams, to perform digital computations.

Quantum Computing

A technology that applies the principles of quantum physics and quantum mechanics to computers to direct atoms or

nuclei to work together as quantum bits (qubits), which function simultaneously as the computer’s processor and memory

Nanotechnology

Nanotechnology. The science of creating tiny

computers and components by working at the individual atomic and molecular levels.

Strategies for Making Faster and Better Computers

Researchers and manufacturers are using several strategies today to continue to build faster

and better personal computers.

Pipelining

The capability of a CPU to begin processing a new instruction as soon as the previous instruction completes the first stage of the

machine cycle.

Improved Materials

" CPU chips used aluminum circuitry etched onto a silicon chip. As the

number of aluminum circuits that can be packed onto a silicon chip without heat damage

or interference approached its limit, chipmakers began to look for alternate materials."

Improved Architecture

Computer manufacturers are continually working to improve the basic architecture of

computers, such as to make them faster, cooler, quieter, more energy efficient, and more

reliable.

Improving the Performance of Your System Todaypic

Several strategies you can use to try to improve the performance of your current computer are discussed next.

Upgrade Your Video Graphics Card

If programs, documents, and other items seem sluggish as they are displayed on your

monitor, you can check to see if a video upgrade might help.

Upgrade Your Internet Connection

"If your system seems slow primarily when you are using the Internet, the culprit might be

your Internet connection."

Buy a Larger or Second Hard Drive

hard drives become less efficient as they fill up. if it is full, buy more storage unites

Perform System Maintenance

uninstall programs to clean the computer from the fragments

Delete the temporary files

Error-check and defragment your hard drive

Scan for computer viruses and spyware continually.

"Clean out the dust from inside the system unit of desktop computers once or twice

a year using a can of compressed air or a small vacuum cleaner."

Add More Memory

more memory is required than was necessary even a

couple of years ago.

overview

This chapter explains how momory, CUPs, and other devices work.

INSIDE THE SYSTEM UNIT

The system unit is the main case of a computer.

Ports and Connectors

port is a connector on the exterior of a computer to which a device may be attached.

Buses

An electronic path on the motherboard or within the CPU or other computer component along which data is transferred.

FireWire/IEEE 1394 Bus

" A high-speed bus standard often used to connect digital video cameras and other multimedia hardware to a computer."

USB Bus

" One of the more versatile bus architectures is the Universal Serial Bus (USB)."

PCI and PCI Express Bus

The PCI (Peripheral Component Interconnect) bus has been one of the most common types of expansion buses in past years.

Frontside Bus (FSB)

"The frontside bus (FSB) connects the CPU to the chipset (most often called the I/O bridge today, though sometimes the older term Northbridge is still used) that connects the CPU to the rest of the bus architecture."

Memory Bus

memory bus is the change that allows for

increased performance; the bus used to connect the CPU to RAM is typically called the

Expansion Slots, Expansion Cards, and ExpressCard Modules

Expansion slot. A location on the motherboard into which expansion cards are inserted.

Expansion card. A circuit board that can be

inserted into an expansion slot location on a computer’s motherboard to add additional functionality or to connect a peripheral device to that

computer.

ExpressCard module. A module that can be inserted into a computer’s ExpressCard slot to add additional functionality or to connect a

peripheral device to that computer; commonly used with notebook computers.

Fans, Heat Sinks, and Other Cooling Components

fans, heat sinks (small components typically made out of aluminum with fins that help to dissipate

heat),

-other methods to cool the CPU and system unit.

Memory

Memory refers to chip-based storage. or known as random access memory or RAM

Flash Memory

Flash memory consists of nonvolatile memory chips that can be used for storage by the

computer or the user.

Read-Only Memory (ROM)

ROM (read-only memory) consists of nonvolatile chips that permanently store data or

programs.

Registers

A register is high-speed memory built into the CPU.

Random Access Memory (RAM)

called main memory, is used to store the essential

parts of the operating system while the computer is running.

The CPU

The central processing unit (CPU) consists of a variety of circuitry and components that packaged together and connected directly to the motherboard.

The CPU also called

the microprocessor (when talking about personal computers) or just the processor

Bus Width, Bus Speed, and Bandwidth

bus is an electronic path over which data can travel.

- bus width—the number of

wires in the bus over which data can travel.

- The bus speed is also a very important factor, since the bus width and bus speed together determine the bus’s throughput or bandwidth

Cache Memory

Cache memory is a special group of very fast memory circuitry located on or close to

the CPU.

Word Size

A computer word is the amount of data

(measured in bits or bytes) that a CPU can

manipulate at one time.

Processing Speed

One measurement of the processing speed of a CPU is the CPU clock speed, which is typically rated in megahertz (MHz) or gigahertz (GHz).( directly quoted from the book).

The Motherboard

A circuit board is a thin board containing computer chips and other electronic components.

data and programing represntation

coding systems are used to represnt data and programs in a manner that can be understood by the computers.

Representing Software Programs: Machine Language

Before a computer can execute any program

instruction, such as requesting input from the user, moving a file from one storage device

to another, or opening a new window on the screen, it must convert the instruction into

a binary code known as machine language( directly quoted from the book).

Coding Systems for Other Types of Data

-numeric and text-based data, which consists of alphanumeric characters and special symbols, such as the comma and dollar sign.

Video Data

is displayed using a collection of frames; each frame contains a still image. when they are played one after one.

Audio Data

samples are digital representations

of the sound at particular moments.

Graphics Data

Graphics data consists of still images, such as photographs or drawings.

- bitmap image an image comprised of a grid of small dots, called pixels

Coding Systems for Text-Based Data

-after numeric data is represented by the binary numbering system, text-based data is

represented by binary coding systems

-ASCII, EBCDIC, and Unicode. These codes are used to represent all characters that can

appear in text data.

Unicode

Unicode is a universal international coding standard designed to represent text-based data written in any ancient or modern language, including those with

different alphabets, such as Chinese, Greek, Hebrew, Amharic, Tibetan, and Russian.

ASCII and EBCDIC

ASCII (American Standard Code for Information Interchange) is the coding system

traditionally used with personal computers.

digital data represtntation

- Virtually all computers today are digital computers. —Such as the embedded computers,

midrange servers, personal computers, mobile devices, mainframes, and supercomputers.

- Most digital computers are binary computers.

- this means that they can understand only two states, off and on.

-represented by the digits 0 and 1.