Module 41: Information Technology Flashcards
Information Systems
An information system processes data and transactions to provide users with the information they need to plan, control and operate an organization, including: -Collecting transaction and other data -Entering it into the information system -Processing the data -Providing users with the information needed -Controlling the process
Types of IT Systems - Office automation systems
Designed to improve productivity by supporting daily work of employees (e.g. word processing, spreadsheets, presentation tools, e-mail, electronic calendars, contract management software)
Types of IT systems - Transaction processing systems
Involve the daily processing of transactions (e.g. airplane reservation systems, payroll recording, cash receipts, cash disbursement)
Types of IT systems - Management reporting systems
Designed to help with the decision making process by providing access to computer data.
Types of IT systems - Management information systems
Systems designed to provide past, present, and future information for planning, organizing and controlling the operations of the organization
Types of IT systems - Decision support systems
Computer-based information systems that combine models and data to resolve nonstructured problems with extensive user involvement.
Types of IT systems - Expert systems
Computer systems that apply reasoning methods to data in a specific relatively structured area to render advice or recommendations, much like a human expert
Types of IT systems - Executive information systems
Computerized systems that are specifically designed to support executive work
Type of computers - Supercomputers
Extremely powerful, high-speed computers used for extremely high-volume and complex processing needs.
Types of computers - Mainframe computers
Large, powerful, high-speed computers. While less powerful than supercomputers, they have traditionally been used for high-volume transaction processing. Clusters of lower cost, less powerful “servers” are increasingly taking over the processing chores of mainframe computers.
Types of computers - Servers
High-powered microcomputers that serve applications and data to clients that are connected via a network (e.g. web servers, database servers). Servers typically have greater capacity (faster processors, more RAM, more storage) than clients (microcomputers) and often act as central repository for organizational data. Servers today are often configured as a virtual machine meaning multiple operating systems can coexist and operate simultaneously on the same machine. Virtual machines are appealing because they lower hardware costs and create energy savings.
Types of computers - Microcomputers (desktop or laptop)
Designed to be used by one person at a time; often called personal computers; typically used for work processing, e-mail, spreadsheets, surfing the web, creating and editing graphics, playing music, gaming
Types of computers - Tablets/Smart Phones/PDAs
These are typically smaller, handheld wireless devices that depend on WiFi and/or cellular technology for communication.
Central processing unit (CPU)
The principal hardware components of a computer. It contains an arithmetic/logic unit, primary memory, and a control unit. The major function of the CPU is to fetch stored instructions and data, decode the instructions, and carry out the instructions
Arithmetic/logic unit
Performs mathematical operations and logical comparisons
Primary memory (storage)
Active data and program steps that are being processed by the CPU; divided into RAM (random-access memory) and ROM (read-only memory). Application programs and data are stored in the RAM at execution time.
Control unit
Interprets program instructions and coordinates input, output, and storage devices
Magnetic tape
Slowest type of storage available because data is stored sequentially. Primarily used for archiving purposes today.
Magnetic disks
Most common storage medium in use on computers today. Magnetic disks are also called hard disks or hard disks drives (HDDs). Disks can be accessed directly.
RAID (Redundant array of independent (previously, inexpensive) disks
Way of storing the same redundantly on multiple magnetic disks. Reduces the likelihood of loss of data.
Compact disks
Discs (CDs) and Digital Video Discs (DVDs). Both are the same physical size and both use optical technology to read and write data to the disc.
Solid State Drives (SSDs)
Use microchips to store data and require no moving parts for read/write operations. Faster and more expensive per gigabyte than CDs, DVDs, and HDDs. Increasingly being used in place of HDDs in microcomputers but cost and limited capacity have constrained their adoption as a primary storage device.
Cloud-Based Storage
Also called “Storage as a Service” (SaaS). This type of storage is hosted offsite, typically by third parties and is accessed via the Internet.
Digital
Series of binary digits (0s and 1s). One binary digit is called a “bit”. A series of 8 bits is referred to as a “byte.” One byte can form a letter, number, or special character.
Analog
The representation that is produced by the fluctuations of a continuous signature (speech, temperature, weight, speed). Use electrical, mechanical, hydraulic or pneumatic devices to transmit the fluctuations in the signal itself to represent information.
Online
Equipment in direct communication with, and under the control of, the CPU. Online also refers to having a connection to the Internet.
Off-Line
Equipment not in direct communication with the CPU; the operator generally must intervene to connect off-line equipment or data to the CPU. Off-line also refers to the absence of an Internet connection.
Console
Terminal used for communication between the operator and the computer
Peripheral equipment
All non-CPU hardware that may be placed under the control of the central processor. Classified as online or off-line, this equipment consists of input, storage, output and communication.
Controllers
Hardware units designed to operate specific input-output units.
Buffer
Temporary store unit used to hold data during computer operations.
MIPS
Millions of instructions per second; a unit for measuring the execution speed of computers.
Key-to-tape and key-to-disk
Data is entered on a magnetic tape and/or disk respectively, and then read into a computer
Visual display terminal/monitors
Uses keyboard to directly enter data into computer.
Input interface
A program that controls the display for the user (usually on a computer monitor) that allows the user to interact with the system
Graphical user interface (GUI)
Uses icons, pictures, and menus instead of text for inputs (e.g. Windows)
Command line interface
Uses text-type commands
Mouse, joystick, light pens
Familiar devices that allow data entry
Touch-sensitive screen
Allows users to enter data from a menu of items by touching the surface of the monitor
Turnaround documents
Documents that are sent to the customer and returned as inputs (e.g. utility bills)
Magnetic tape reader
A device capable of sensing information recorded as magnetic spots on magnetic tape
Magnetic ink character reader (MICR)
Device that reads characters that have been encoded with a magnetic ink (e.g. bank check readers)
Scanner
A device that reads characters on printed pages
Automatic teller machine (ATM)
A machine used to execute and record transactions with financial institutions
Radio Frequency Identification (RFID)
Uses radio waves to track and input data. Increasingly used for inventory and contactless payment systems. Does not require line-of-sight access like bar code technology (e.g. FasTrak)
Point-of-sale (POS) recorders
Devices that read price and product code data (e.g. recall purchasing groceries - items are frequently passed over a POS recorder). POS processing allows one to record and track customer orders, process credit and debit cards, connect to other systems in a network and manage inventory.
Voice Recognition
A system that understands spoken words and transmits them into a computer.
Electronic commerce and Electronic Data Interchange
Invoices one company’s computer communicating with another’s computer. E.g a buyer electronically sending a purchase order to a supplier.
Monitors
Visually display output
Printers
Produce paper output
Plotters
Produce paper output of graphs
Computer output to microfilm or microfiche (COM)
Makes use of photographic process to store output
Operating system
Manages the input, output, processing and storage devices and operations of a computer (e.g. Windows, Linux, Unix)
Utility programs
Handle common file, data manipulation and housekeeping tasks
Communications software
Controls and supports transmission between computers, computers and monitors, and accesses various databases.
Low-end accounting software
All in one package, designed for small organizations
High-end accounting software
Ordinarily in modules (e.g. general ledger, receivables)
Enterprise Resource Planning (ERP)
Designed as relatively complete information system “suites” for large and medium size organizations (e.g. HR, financial applications, manufacturing, distribution). Major vendors are SAP, PeopleSoft, Oracle, and J.D. Edwards
Compiler
Produces a machine language object program from a source program language
Multiprocessing
Simultaneous execution of two or more tasks, usually by two or more CPUs that are part of the same system
Multitasking
The simultaneous processing of several jobs on a computer
Object program
The converted source program that was changed using a compiler to create a set of machine readable instructions that the CPU understands
Source program
A program written in a language from which statements are translated into machine language; computer programming has developed in generations
Machine language
Composed of combinations of 1’s and 0’s that are meaningful to the computer
Assembly language
Low-level programming language that uses words (mnemonics) instead of numbers to perform an operation. Must be translated to machine language by an assembler. Assembly language is specific to a computer architecture and not portable.
High-level programming languages
COBOL, Basic, Fortran, C++, Java
Object-oriented programs
C++ and Java; based on concept of an objcet which is a data structure that uses a set of routines called methods which operate on the data. Keep together data structures and procedures (methods) through a procedure referred to as encapsulation.
Application-Specific Language
Built around database systems. These programs are ordinarily closer to human languages than the first three generations (e.g. SQL, Structures Query Language)
Virtual memory (storage)
Online secondary memory that is used as an extension of primary memory, thus giving the appearance of larger, virtually unlimited internal memory
Protocol
Rules determining the required format and methods for transmission of data
Desk checking
Review of a program by the programmer for errors before the program is run and debugged on the computer.
Debug
To find and eliminate errors in a computer program. Many compilers assist debugging by listing errors in a program such as invalid commands.
Edit
To correct input data prior to processing
Loop
A set of program instructions performed repetitively a predetermined number of times, or until all of a particular type of data has been processed.
Memory dump
A listing of the contents of storage
Patch
A section of coding inserted into a program to correct a mistake or to alter a routine
Run
A complete cycle of a program including input, processing, and output
Batch
Transactions flow through the system in groups of like transactions (batches) E.g. all cash receipts on accounts receivable for a day may be aggregated and run as a batch.
Online real-time (aka direct access processing)
General: Transactions are processed in the order in which they occur, regardless of type. data files and programs are stored online so that updating can take place as the edited data flows to the application. System security must be in place to restrict access to programs and data to authorized personals.
Online transaction processing (OLTP)
Databases that support day-to-day operations. E.g. airline reservation systems, bank automatic teller systems, and internet website sales systems
Online analytical processing (OLAP)
Category of software technology that enables the user to query the system (retrieve data) and conduct an analysis ordinarily while the user is at a PC
Data warehouse
Subject-oriented, integrated collection of data used to support management decision-making processes
Data mart
Data warehouse that is limited in scope
Data mining
Using sophisticated techniques from statistics, artificial intelligence and computer graphics to explain, confirm and explore relationships among data
Business intelligence (BI)
A combination of systems that help aggregate, access, and analyze business data and assist in the business decision-making process
Artificial intelligence (AI)
Computer software designed to help humans make decisions. AI may be viewed as an attempt to mode aspects of human thought on computers.
Expert system
Form of AI. A computerized information system that guides decision processes within a well-defined area and allows decisions comparable to those of an expert. Modeled into a mathematical system.
Example of an Expert System
Used by a credit card department to authorize credit card purchases so as to minimize fraud and credit losses.
Centralized
-Processing occurs at one location -This is the model used in which a mainframe computer processes data submitted to it through terminals
Decentralized
-Processing (and data) are stored on computers at multiple locations -Computers involved are not interconnected by a network, so users at various sites cannot share data. -Viewed as a collection of independent databases, rather than a single database -End-user computing is relatively decentralized.
Distributed
-Transactions for a single database are processed at various sites -Processing may be on either a batch or online real-time basis -Overall single data base is ordinarily updated for these transactions and available at the various sites
Bit
Binary digit (0 or 1) which is the smallest storage unit in a computer
Byte
A group of adjacent bits (usually 8) that is treated as a single unit, or character, by the computer
Field
A group of related characters (e.g. social security number)
Record
An ordered set of logically related fields. E.g. all payroll data (included the SSN field and others) relating to a single employee
File
A group of related records (e.g. all the weekly pay records YTD), which is usually arranged in a sequence.
Table
Group of related records in a relational database with a unique identifier (primary key field) in each record
Database
A group of related files or a group of related tables (if a relational database)
Array
An aggregate that consists of data objects with attributes, each of which may be uniquely referenced by an index (address). E.g. an array may be used to request input of various payroll information for a new employee in one step. Thus an array could include: employee name, SSN, withholdings, pay rate
Master file
A file containing relatively permanent information used as a source of reference and periodically updated with a detail (transaction) file (e.g. permanent payroll records)
Detail or transaction file
A file containing current transaction information used to update the master file (e.g. hours worked by each employee during the current period used to update the payroll master file)
Traditional file processing systems
Systems focus upon data processing needs of individual departments. Each application program or system is developed to meet needs of particular requesting department or user group.
Advantages of traditional processing systems
-Currently operational for many existing (legacy) systems -Cost effective for simple applications
Disadvantages oft traditional processing systems
-Data files are dependent upon a particular application program -In complex business situation there is much duplication of data b/w data files -Each application must be developed individually -Program maintenance is expensive -Data may be isolated and difficult to share b/w functional areas
Database
Collection of interrelated files, ordinarily most of which are stored online
Normalization
The process of separating the database into logical tables to avoid certain kinds of updating difficulties (referred to as anomalies)
Database system
Computer hardware and software that enables the database to be implemented
Database management system
Software that provides a facility for communications between various applications programs (e.g. a payroll prep program) and the database (e.g. a payroll master file containing the earnings records of the employees)
Data independence
Basic to database systems is this concept which separates the data from the related application programs
Data modeling
Identifying and organizing a database’s data, both logically and physically. Determines what information is to be contained in a database, how the info will be used and how the items in the database will be related to each other
Entity-relationship modeling
An approach to data modeling. Divides the database in two logical parts. E.g. Customer, product and relations are buys and pays for
Primary key
The field(s) that make a record in a relational database table unique
Foreign key
The field(s) that are common to two (or more) related tables in a relational database
REA data model
Data model designed for use in designing accounting information databases. REA is an acronym for the model’s basic types of objects: Resources - Identifiable objects that have economic value Events - An organization’s business activities Agents - People or organizations about which data is collected
Data Dictionary
AKA data repository or data directory system; a data structure that stores meta-data
Meta-data
Definitional data that provides information about or documentation of other data managed within an application or environment. For example, data about data elements, and data structures (length, fields, columns, etc.)
Structured query language (SQL)
The most common language used for creating and querying relational databases
Data definition language (DDL)
Used to define a database, including creating, altering, and deleting tables and establishing various constraints.
Data manipulation language (DML)
Commands used to maintain and query a database, including updating, inserting in, modifying and querying (asking for data). E.g. frequent query involves the joining of information from more than one table
Data control language (DCL)
Commands used to control a database, including controlling which users have various privileges (e.g. who is able to read from and write to various portions of the database)
Database structures - Hierarchical
The data elements at one level “own” the data elements at the next lower level (think of an organization chart in which one manager supervises several assistants, who in turn each supervise several lower level employees)
Database structures - Networked
Each data element can have several owners and can own several other elements (think of a matrix type structure in which various relationships can be supported)
Database structures - Relational
A database with the logical structure of a group of related spreadsheets. Each row represents a record, which is an accumulation of all the fields related to the same identifier or key; each column represents a field common to all of the records
Database structures - Object-oriented
Information (attributes and methods) are included in structures called object classes. This is the newest database management system technology.
Database structures - Object-relational
Includes both relational and object-oriented features
Database structures - distributed
A single database that is spread physically across computers in multiple locations that are connected by a data communications link.
User department
Because users directly input data, strict controls over who is authorized to read and/or change the database are necessary.
Access controls
In addition to the usual controls over terminals and access to the system, database processing also maintains controls within the database itself. These controls limit the user to reading and/or changing (updating) only authorized portions of the database.
Restricting privileges
This limits the access of users to the database, as well as operations a particular user may be able to perform. For example, certain employees and customers may have only read and not write privileges
Logical views
Users may be provided with authorized views of only the portions of the database for which they have a valid need.
Backup and recovery
Database is updated on a continuous basis during the day.
Backup of database and logs of transactions (aka systems logs)
Approach is to backup the entire database several times per week, generally to magnetic tape. A log of all transactions is also maintained.
Database replication
To avoid catastrophic failure, another approach is to replicate the database at one or more locations. Thus, all data may be recorded to both sets of the database.
Backup facility
Another approach is to maintain a backup facility with a vendor who will process data in case of an emergency.
Database administrator (DBA)
Individual responsible for maintaining the database and restricting access to the database to authorized personnel
Audit software
Usually used by auditors to test the database
Data independence
Data can be used relatively easily by differing applications