CC1 (Chapter 2)

Coding Systems

Used to represent data and programs in a manner understood by the computer.

Digital Computers

They can only understand two states, off and on (0 and 1).

Digital Data Representation

The process of representing data in digital form so a computer can understand it.

Bit

The smallest unit of data that a binary computer can recognize (a single 1 or 0).

Byte

used to express the size of documents and other files, programs, etc.

Is equal to 8 bits.

Prefixes

are often used to express larger quantities of bytes.

Numbering system

A way of representing numbers

Decimal numbering system

Uses 10 symbols (0-9)

Binary numbering system

Uses only two symbols (1 and 0) to represent all possible numbers

ASCII (American Standard Code for Information Interchange)

Coding system traditionally used with personal computers

EBCDIC (Extended Binary-Coded Decimal Interchange Code)

Developed by IBM, primarily for mainframes

Unicode

Newer code (32 bits per character is common).

Universal coding standard designed to represent text- based data written in any ancient or modern language.

Replacing ASCII as the primary text-coding system.

Graphics Data

still images such as photos or drawings.

Bitmapped images

Image made up of a grid of small dots called pixels

Audio Data

The audio must be in digital form in order to be stored on or processed by a computer.

Video Data

Displayed using a collection of frames, each frame contains a still image.

Machine Language

Binary-based language for representing computer programs the computer can execute directly.

System Unit

The main case of a computer.

Houses the processing hardware for a computer.

Also contains storage devices, the power supply, and cooling fans.

Houses processor, memory, and interfaces to connect to peripheral devices (printers, etc), and other components.

Motherboard

Consists of computer chip, circuit board, and system board.

Computer Chip

Very small pieces of silicon or other semi-conducting material onto which integrated circuits are embedded.

Circuit Board

A thin board containing computer chips and other electronic components.

System Board

The main circuit board inside the system unit to which all devices must connect.

External Devices

monitors, keyboards, mice, printers

Wireless Devices

e.g., Bluetooth

Power Supply

Connects to the motherboard to deliver electricity (personal computer).

Drive Bays

Rectangular metal racks inside the system unit that house storage devices.

e.g., Hard drive, CD/DVD drive, flash memory card reader

Connected to the motherboard with a cable.

CPU (Central Processing Unit)

Circuitry and components packaged together and connected directly to the motherboard.

Does the vast majority of processing for a computer.

Also called a processor; called a microprocessor when talking about personal computers

Transistor

Key element of the microprocessor.

Made of semi-conductor material that acts like a switch controlling the flow of electrons inside a chip.

Today’s CPUs contain hundreds of millions of them; the number doubles about every 18 months (Moore’s Law)

Dual-core CPU

Contains the processing components (cores) of two separate processors on a single CPU.

Quad-core CPU

Contains four cores

Multi-core processors

allow computers to work on more than one task at a time

GPU (Graphics Processing Unit)

Takes care of the processing needed to display images (including still images, animations) on the screen.

Can be located on the motherboard, on a video graphics board, on in the CPU package.

Processing Speed

Rated in megahertz (MHz) or gigahertz (GHz).

Higher CPU clock speed = more instructions processed per second.

CPU Clock Speed

is one measurement of processing speed.

Word Size

The amount of data that a CPU can manipulate at one time.

Typically 32 or 64 bits.

Cache Memory

Special group of very fast memory chips located on or close to the CPU.

Usually internal cache (built into the CPU).

Bus

An electronic path within a computer over which data travels.

Located within the CPU and etched onto the motherboard.

Expansion Bus

Connects the CPU to peripheral (typically input and output) devices.

Bus Width

is the number of wires in the bus over which data can travel

Bandwidth

The amount of data that can be transferred by the bus in a given time period.

Memory

Refers to chip-based storage located inside the system unit.

Storage

refers to the amount of long-term storage available to a computer

Random Access Memory (RAM)

Computer’s main memory.

Consists of chips arranged on a circuit board called a memory module which are plugged into the motherboard.

Stores essential parts of operating system, programs, and data the computer is currently using.

Volatile

RAM content lost when the computer is shut off.

ROM and flash memory are non-volatile.

Registers

High-speed memory built into the CPU.

Used to store data and intermediary results during processing.

Fastest type of memory.

Read-Only Memory (ROM)

Non-volatile chips located on the motherboard into which data or programs have been permanently stored.

Retrieved by the computer when needed.

Being replaced with flash memory.

Flash Memory

Nonvolatile memory chips that can be used for storage.

Have begun to replace ROM for storing system information.

Fans

used on most personal computers to help cool the CPU and system unit.

Heat Sinks

Small components typically made out of aluminum with fins that help to dissipate heat.

• Liquid cooling systems

• Immersion cooling

• Notebook cooling stand

Examples of Cooling Systems

Liquid cooling systems

Cool the computer with liquid-filled tubes.

Immersion Cooling

Hardware is actually submerged into units filled with a liquid cooling solution.

Notebook cooling stand

Cools the underside of a notebook computer.

Expansion Slot

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

Expansion Card

A circuit board inserted into an expansion slot.

Used to add additional functionality or to attach a peripheral device.

Express Card Modules

Designed to add additional functionality to notebooks

Memory Bus

Connects CPU directly to RAM.

Frontside Bus (FSB)

Connects CPU to the chipset that connects the CPU to the rest of the bus architecture.

PCI Bus

has been one of the most common types of bus

PCI Express (PCIe) Bus

is extremely fast bus, has replaced the PCI bus

Universal Serial Bus (USB)

Extremely versatile.

Allows 127 different devices to connect to a computer via a single USB port.

FireWire Bus

Developed by Apple to connect multimedia devices to a computer.

Port

A connector on the exterior of a computer’s system unit to which a device may be attached.

Tablet Docks

Used to help with tablet productivity

Some are just a stand

Moore’s Law

In 1965, Gordon Moore predicted that the number of transistors per square inch on chips had doubled every two years and that trend would continue.

• Arithmetic/Logic Unit (ALU)

• Floating Point Unit (FPU)

• Control Unit

• Prefetch Unit

• Decode Unit

• Registers and Internal Cache Memory

• Bus Interface Unit

Typical CPU Components:

Arithmetic Logic Unit (ALU)

Performs arithmetic involving integers and logical operations

Floating Point Unit (FPU)

Performs decimal arithmetic

Control Unit

Coordinates and controls activities within a CPU core

Prefetch Unit

Attempts to retrieve data and instructions before they are needed for processing in order to avoid delays

Decode Unit

Translates instructions from the prefetch unit so they are understood by the control unit, ALU, and FPU

Registers and Internal Cache Memory

Store data and instructions needed by the CPU

Bus Interface Unit

Allows the core to communicate with other CPU components

System Clock

Small quartz crystal on the motherboard

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

Nanotechnology

The science of creating tiny computers and components less than 100 nanometers in size.

Carbon nanotubes (CNTs)

used in many products today

Quantum Computing

Applies the principles of quantum physics and quantum mechanics to computers.

Utilizes atoms or nuclei working together as quantum bits (qubits).

Expected to be used for specialized applications, such as encryption and code breaking.