Savitch Java: An Introduction to Problem Solving and Programming 7th Edition, Chapters 1-6

What is a bit?

Binary Digit (0 or 1)

Bit Patterns are

used to represent information such as numbers, text characters, images, sound, and others.

Boolean Operations are

operations that manipulates one or more true/false value.

Examples of Specific Operations are

AND, OR, XOR (exclusive or), NOT

A Gate is

A device that computes a Boolean Operation

A Flip-flop is

A circuit built from gates that can store one bit.

Hexadecimal notation is

A shorthand notation for long bit patterns

A Cell is

A unit of main memory

A Byte =

8 bits

Most Significant Bit is

the bit at the left end of the conceptual row of bits in a memory cell

Least Significant Bit is

the bit at the right end of the conceptual row of bits in a memory cell

Address is

A "name" that uniquely identifies one cell in the computer's main memory

RAM (Random Access Memory)

Memory in which individual cells can be easily accessed in any order

Dynamic Memory (DRAM)

RAM composed of volatile memory

Kilobyte

210 bytes = 1024 bytes

Megabyte

220 bytes = 1,048,576 bytes

Gigabyte

230 bytes = 1,073,741,824 bytes

A gate is an example of

VLSI (Very Large Scale Integration)

A gate provides

the building blocks from which computers are constructed

A gate is often implemented as

small electronic circuits

Two functions of Hexadecimal notation

are to divide patterns into groups of four bits each and to represent each group by a single symbol

VLSI stands for

Very Large Scale Integration

Some devices for mass storage include

Magnetic disks, CDs, DVDs, magnetic tapes, flash drives, solid-state disks

Some advantages that mass storage has over main memory include

less volatility, larger storage capacities, lower costs, can be removed

Flash Memory

circuits that that trap electrons in tiny silicon dioxide chambers

A flash drive uses

flash memory

When erasing flash memory you are

slowly damaging the media

Flash memory is the mass storage of choice for

digital cameras, smartphones

SD Cards

provide GB's of storage

Each character when representing text is

assigned a unique bit pattern

ASCII

uses pattern of 7-bits to represent most symbols used in written English text

ISO

developed a number of 8 bit extensions to ASCII

Unicode

uses patterns of up to 21 bits to represent the symbols used in languages world wide, 16-bits for world's commonly used languages

Binary notation

Uses bits to represent a number in base two

Some limitations of computer representations of numeric values are

overflow and truncation

Truncation

occurs when a value cannot be represented accurately

Overflow

occurs when a value is too big to be represented

A use of MIDI

is that it is in music synthesizers and records "musical score"

Pixel

is short for "picture element"

Bit map techniques and Vector techniques both

represent images

Sampling techniques and MIDI

both represent sound

Uses of sampling techniques

high quality recording and actual audio

Pixels, RGB, Luminance and Chrominance

are bit map techniques

The binary system is based on

powers of two

The traditional decimal system is based on

powers of ten

The CPU is

the central processing unit

Two types of registers are

general purpose and special purpose

Machine instruction

an instruction encoded as a bit pattern recognizable by the CPU

Machine language

the set of all instructions recognized by a machine

RISC

Reduced Instruction Set Computing

CISC

Complex Instruction Set Computing

Data transfer is

when you copy data from one location to another

The function of the arithmetic/logic unit is to

use existing bit patterns to compute a new bit pattern

The function of the control unit is to

direct the execution of the program

The function of data transfer is to

copy data from one location to another

The function of the arithmetic/logic unit is to

use existing bit patterns to compute a new bit pattern

Op-code

specifies which operation should execute

Operand

gives more detailed information about the operation

Op-codes and Operands

are both parts of a machine instruction

RISC and CISC

are both machine Language Philosophies

Data Transfer, Arithmetic/Logic, Control

are all machine instruction types

Program execution

machine cycle and registers are 2 facets of

Machine Cycle

composed of fetch, decode, execute

Program Counter

address of next instruction

Instruction Register

current instruction

Rotate and Shift

circular shift, logical shift, arithmetic shift

Arithmetic

add, subtract, multiply, divide

Logic, Rotate and Shift, and Arithmetic are all

Arithmetic/Logic Operations

Algorithm

An ordered set of unambiguous, executable steps that defines a terminating process

Algorithm Representation

Requires well-defined primitives, a collection of primitives constitutes a programming language

To solve an algorithm you first need to

get a foot in the door

Iterative Structures

loops

Recursion

The execution of a procedure leads to another execution of the procedure, Multiple activations of the procedure are formed, all but one of which are waiting for other activations to complete.

Algorithm Efficiency

Measured as number of instructions executed.

Program variables or identifiers

Descriptive names for memory locations, chosen by the programmer.

Assembly Language Characteristics

One-to-one correspondence between machine instructions and assembly instructions, Inherently machine-dependent, Converted to machine language by a program called an assembler

Data Types

Integer: Whole numbers
Real (float): Numbers with fractions
Character: Symbols
Boolean: True/false

Procedural Units

Subprogram, subroutine, procedure, method, function

Object

Active program unit containing both data and procedures

Class

A template from which objects are constructed

An object is

an instance of a class

Instance Variable

Variable within an object, Holds information within the object

Method

Procedure within an object, Describes the actions that the object can perform

Constructor

Special method used to initialize a new object when it is first constructed

Encapsulation

A way of restricting access to the internal components of an object, Private, Public

Inheritance

Allows new classes to be defined in terms of previously defined classes

Polymorphism

Allows method calls to be interpreted by the object that receives the call

Security Problems

insecure passwords, sniffing software, attacks from within

Security counter measures

auditing software

Process

the activity of executing a program

Process state

current status of the activity

Scheduler

Adds new processes to the process table and removes completed processes from the process table

Dispatcher

Controls the allocation of time slices to the processes in the process table

Interrupt

end of a time slice

User Interface

Communicates with users

Kernel

Performs basic required functions

Boot loader

Program in ROM

Directory

A user-created bundle of files and other directories

Directory Path

A sequence of directories within directories

Encryption

the process of converting information or data into a code, especially to prevent unauthorized access.