MIS - Exam #1

Computer

Computer

A machine that accepts data as input, processes data without human intervention using stored instruction, and outputs information

Source Code (Program)

Must be translated into object code consisting of binary 0s and 1s (input to the complier)

Object Code

Created by complier, binary digits (output of the compiler)

Garbage in, garbage out (GIGO)

If input data is erroneous, the information provided by the computer is also erroneous

Hardware components

physical devices (keyboards, monitors, and processing units)

Software Components

Programs written in computer languages

Computer performs three basic tasks

arithmetic operations, logical operation, & storage and retrival operations

Central Processing Units (CPU)

Computers can either have a single processor or multiprocessors

Bus

link between devices connected to the computer

Disk drive

peripheral device for recording, storing, and retrieving information

CPU case

enclosure containing the computer’s main components

Motherboard

main circuit board containing connectors for attaching additional boards

speed, accuracy, storage, and retrieval capabilities

Computer draw their power from 3 factors

Speed

rate at which a computer performs instructions

Millisecond

1/1,000 of a second

Microsecond

1/1,000,000 of a second

Nanosecond

1/1,000,000,000 of a second

Picosecond

1/1,000,000,000,000 of a second

Accuracy

computer’s usage of values close to the true values, degree of accuracy is critical in many computer applications

Storage

saving data in a computer memory

retrieval

accessing data from memory

Bits

what data is stored in

American Standard code for information interchange (ASCII)

data code for text files, PC applications, and the internet

1 bit

a single value of 0 or 1

8 bits

1 byte or character

Input, Output, Memory

To use a computer and process data, three major components are needed

Input Devices

Send data and information to the computer (keyboard, mouse, barcode reader, etc.)

Output Devices

Receive and displays the results from the computer (head phones, printer, speakers, etc.)

Main memory

stores data and information, directly accessed by the CPU, usually volatile

Secondary memory

stores data and information, nonvolatile, serves as archival storage

Random Access Memory (RAM)

Volatile memory, in which data can be read from and written to (Cache RAM - stores. recently accessed memory)

Read-only (ROM)

nonvolatile, data can be read but cannot be written to the memory, typically stores BIOS information, and the computer system’s clock

Cloud Storage

Online storage and backup of data, commonly involves multiple virtual servers, usually hosted by third parties, customers usually buy or lease storage space based on needs

Storage Area Network (SAN)

dedicated high-speed network consisting of both hardware and software

Network-attached storage (NAS)

Network-connected computer dedicated to provide file-based data storage services to other network devices

Server

computer and all the software for managing network resources and offering services to a network

Software

the programs that run a computer system

System Software

Programs for operating the hardware components and the application software (what you want the computer to do) (Microsoft Windows)

Application Software

Programs employed by end users to perform specific tasks (use to run the machine) (Microsoft Excel and Microsoft Access)

Operating System Software

Set of programs for controlling and managing computer hardware and software

Supervisor Program

Responsible for controlling all other programs in the OS

Kernal

Program at the core of an operating system, connects the application software to the hardware components, controls everything that occurs in the system

Application Software

Commercial software or software developed in house; used to perform a variety of tasks on a personal computer (zoom, google docs, etc.

Machine Language

first generation of computer languages, consists of a series of 0s and 1s representing data or instructions

Assembly Language

Second generation of computer languages, higher-level language than machine language

High-level languages

third-generation of computer languages

Fourth-generation Languages (4GLs)

Uses macro codes replacing several lines of programming, commands are powerful and easy to learn

Fifth-generation Languages (5GLs)

use artificial intelligence technologies, designed to facilitate natural conversations between an individual and the computer (siri, google)

Database

collection of related data that is stored in a central location or in multiple locations

Data Hierarchy

Structure and organization of data, which involves fields, records, and files

Database Management System (DBMS)

Software for creating, strong, maintaining, and accessing database files

Internal Data

Collected from within an organization, stored in the organizations internal database

External Data

Comes from a variety of sources, stored in a data warehouse

Sequential access file structure

records in files are organized and processed in numerical or sequential order, organized based on a primary key, used for backup and archive files

Random access file structure

Records can be accessed in any order, regardless of their physical locations in storage media, (data is small)

Indexed sequential access method (ISAM)

Records accessed sequentially or randomly, depending on the number accessed

Physical View

How data is stored on and retrieved from storage media

Logical View

How information appears to users and how it can be organized and retrieved

Data Structure

describes how data is organized and related

operations

describe methods and calculations performed on data

Integrity rules

define the boundaries of the database

Hierarchical Model

Relationships between records from a treelike structure

Network Model

Similar to the hierarchical model but records are organized differently

Relational Databases

Stores data in the form of relations

Attribute

the properties that define a relation

Relation Schema

represents the relation’s name with its attributes

Tuple

Each row in the relation is known

Relation Instance

The set of tuples of a relation at a particular time

Degree

The number of attributes in the relation is known as the degree of the relation

Cardinality

The number of unique values in a relational table

NULL Values

The value that is unknown or unavailable

Data dictionary

Stores definitions, such as data types for fields, default values, and validation rules for data in each field (first step)

Super Key

is a set of one or more attributes that are taken collectively and can identify all other attributes uniquely

Candidate Key

The minimal set of attributes that can uniquely identify a tuple (the minimum combination)

Primary Key

There can be more than one candidate key in relation, out of which one can be chosen as the primary key.

Foreign Key

If an attribute can only take the values which are present as values of some other attribute

Normalization

Process of structuring a relational database with standard normal forms

Operations

Relational DBMS retrieves data from tables using operations that pick and combine data from one or more table

Database Engine

Responsible for data storage, manipulation, and retrieval (the heart of the data base)

Data Definition

Used to create and maintain the data dictionary (what is inside the data)

Data Manipulation

Used to add, delete, modify, and retrieve records from a database

Application Generation

designs elements of an application using a database

Data Administration

Used for tasks such as backup and recovery, security, and change management

Database Administrators

Handle database design and management

Data-driven Web sites

Retrieve data and allows users to enter data in the database, improve access to information

Distributed Database Management System (DDBMS)

Stores data on multiple servers throughout an organization

Fragmentation

addresses how tables are divided among multiple locations

Replication

each site stores a copy of the data in the organization’s database

Allocation

combines fragmentation and replication

Object-Oriented Databases

Data and their relationships are contained in a single object

Encapsulation

grouping objects along with their attributes and methods into a class

Inheritance

new objects can be created faster and more easily by entering new data in attributes

Data Warehouse

Collection of data from a variety of sources

Raw Data

Data in its original form

Summary Data

Data on the subtotals of various categories

Metadata

Data about the data (data’s content, quality, condition, origin, and other characteristics)

Online Transaction Processing (OLTP)

Used by transaction-oriented application, used to analyze transaction-oriented data

Online Analytical Processing (OLAP)

Used to generate business intelligence, uses to analyze data from multiple sources, involves multidimensional analysis

Data-mining analysis

Involves examining the data to discover patterns and relationships

Decision-making reports

Involves creating reports used for decision-making