Flashcards in IT Operations Deck (56):
Define a "bit" (binary digit).
An individual zero or one; the smallest piece of information that can be represented.
A group of (usually) eight bits that are used to represent alphabetic and numeric characters and other symbols (3, g, X, ?, etc.). Several coding systems are used to assign specific bytes to characters. ASCII and EBCIDIC are the two most commonly used coding systems. Each system defines the sequence of zeros and ones that represent each character.
A group of characters (bytes) that identify a characteristic of an entity. A data value is a specific value found in a field. Fields can consist of a single character (Y, N) but usually consist of a group of characters. Each field is defined as a specific data type. Date, Text and Number are common data types.
A group of related fields (or attributes) that describe an individual instance of an entity (a specific invoice, a particular customer, an individual product).
A collection of records for one specific entity (an Invoice File, a Customer File, a Product File). In a relational database environment, files are also known as tables.
Define "systems software."
The programs that run the computer and support system management operations.
Define "operating system."
The interface between the user and the computer hardware.
Define "programming languages."
All software is created using programming languages. They consist of sets of instructions and a syntax that determine how the instructions can be put together.
Define "application software."
The diverse group of end-user programs that accomplish specific user objectives. Can be general purpose (word processors, spreadsheets, databases) or custom-developed for a specific application (ex.: a marketing information system for a clothing designer). May be purchased "off the shelf" or developed internally.
What constitutes computer hardware?
This includes the physical equipment in your computer and the equipment that your computer uses to connect to other computers or computer networks.
What is a "central processing unit (CPU)"?
The CPU is the control center of the computer system. It has three principal components.
What data is stored in random access memory (RAM)?
A temporary data store for information in process.
How is read-only memory (ROM) used?
Used to permanently store the data needed to power on the computer; includes portions of the operating system.
What is the purpose of secondary storage devices?
Provide permanent storage for programs and data. Depending on the way the devices are set up, they can either be online (the data on the device is available for immediate access by the CPU) or offline (the device is stored in an area where the data is not accessible to the CPU).
What are magnetic disks?
These are random access devices. Data can be stored on, and retrieved from, the disk in any order. This is the most efficient way to store and retrieve individual records. Magnetic disks are the most commonly used form of secondary storage.
What is an optical disk?
These use laser technology to "burn" data on the disk (although some rewritable disks use magnetic technology to record data). In general, read-only and write-once optical disks are a more stable storage medium than magnetic disks. Optical disks, like magnetic disks are random access devices. There are several different types of optical disks.
What are flash drives (also known as jump drives or thumb drives)?
Small, portable devices that can store anywhere from 500 megabytes to several gigabytes. The term "drive" is a bit of a misnomer as there are no moving parts to the "drive." Rather, the memory in a flash drive is similar to the RAM used as primary storage for your CPU.
Define "supercomputers." What are they used for?
Computers at the leading edge of processing capacity. Used for calculation-intensive scientific applications, for example, weather forecasting and climate research.
What is a "mainframe computer."
Computers used by commercial organizations to support mission critical tasks such as sales and order processing, inventory management, and e-commerce applications. Unlike supercomputers, which tend to support processor-intensive activities (i.e., a small number of highly complex calculations), mainframe computers tend to be input/output (I/O) intensive (i.e., a very large numbers of simple transactions). Mainframes frequently support thousands of users at a single point in time.
Define "batch processing."
Periodic transaction processing method in which transactions are processed in groups
What are "time lags" in batch processing systems?
This is an inherent part of batch processing. There is always a time delay between the time the transaction occurs, the time that the transaction is recorded, and the time that the master file is updated.
Define "online, real-time (OLRT) processing."
Continuous, immediate transaction processing method in which transactions are processed individually as they occur.
What are point-of-sale (POS) systems?
Combine on-line, real-time processing with automated data capture technology, resulting in a system that is highly accurate, reliable, and timely.
What are subsidiary ledgers (sub-ledgers)?
These ledgers classify transactions by alternative accounts (e.g., customer accounts, vendor accounts, product accounts).
What is the Accounts Receivable (A/R) sub-ledger?
This ledger classifies A/R transactions (credit sales and customer payments) by Customer.
Define "master files."
Computerized data files equivalent to the ledgers found in manual accounting system.
Define "transaction files."
Computerized data files equivalent to the journals found in a manual accounting system.
What are centralized systems?
Maintain all data and perform all data processing at a central location; remote users may access the centralized data files via a telecommunications channel, but all processing is centralized.
What are distributed database systems?
Database is distributed across locations according to their needs (note the subtle reference to Karl Marx here. . .)
What is a decentralized system?
Each location maintain separate system and data.
What is a "computer network"?
Two or more computing devices connected by a communication channel on which the devices exchange data.
What is a "node"?
A device connected to a computer network.
What is a "client" on a computer network?
A node, usually a microcomputer, which is used by end users; uses but usually does not supply network resources.
Wireless transmission medium. It uses the same radio frequencies as Wi-Fi, but with lower power consumption resulting in a weaker connection. It is used to provide a direct communications link between two devices (e.g., a cell phone and ear piece, computer and a printer).
Whant is a "peer-to-peer network"?
A network system in which all nodes share in communications management. No central controller (server) is required. These systems are relatively simple and inexpensive to implement; used by LANs.
What is a "client/server system"?
A central machine (the server) mediates communication on the network and grants access to network resources. Client machines use of network resources and also perform data processing functions; used by LANs.
What is a "local area networks (LAN)" ?
Originally confined to very limited geographic areas (a floor of a building, a building, or possibly a couple of buildings in very close proximity to each other). Inexpensive fiber optic cable now enables local area networks to extend many miles.
What is a wide area network (WAN)?
These networks vary dramatically in geographic coverage. Most WANs are national or international in scope.
Define "file server."
In a local area network, a computer that provides centralized access to program and data files.
What is a "server"?
Computer or other device on a network which only provides resources to the network and is not available (normally) to individual users; examples include print servers, file servers, and communications servers. Contrast with a workstation.
A "network of networks:" a global network of millions of interconnected computers and computer networks.
Define "Transmission Control Protocol / Internet Protocol (TCP/IP)".
The core protocol transmission of the internet.
Available only to members of the organization (business, school, association); often used to connect geographically separate LANs within a company.
Open to an organization's associates (company suppliers, customers, business partners, etc.) to access data that is relevant to them.
What is extensible markup language (XML)?
Protocol for encoding (tagging) documents in machine-readable form.
What is extensible business reporting language (XBRL)?
XML-based protocol for encoding and tagging business information. A means to consistently and efficiently identify the content of business and accounting information in electronic form.
What makes a computer language extensible?
Users can create taxonomies for specific environments, for example for the purpose of taxation reporting, environmental regulation reporting, or automobile manufacturing.
Define "hypertext markup language (HTML)".
Core "markup" language (a way of tagging text) for web pages. The basic building-block protocol for constructing webpages.
What is "File Transfer Protocol (FTP)"?
A protocol used for file transfer applications.
What is "instant messaging (IM)"?
A protocol for instant messaging.
Define "grandfather-father-son file security control."
A technique used to maintain redundant backup copies (three "generations") of data files; backup files are used to recover from systems failures in which data files are damaged or destroyed.
A method of backup consisting of the maintenance of an exact copy of a data set to provide multiple sources of the same information. Mirrored sites are most frequently used in e-commerce for load balancing - distributing excess demand from the primary site to the mirrored.
Define "storage area networks (SANs)."
A method of backup that can be used to replicate data from multiple sites. Data stored on a SAN is immediately available without the need to recover it. This enables highly efficient disaster recovery.
Define "remote backup service."
A service that provides users with an online system for backing up and storing computer files. Remote backup has several advantages over traditional backup methodologies: the task of creating and maintaining backup files is removed from the IT department's responsibilities; the backups are maintained off site; some services can operate continuously, backing up each transaction as it occurs.
Describe the rollback and recovery backup and recovery system methodology.
A backup and recovery system method that is common to online, real-time processing. All transactions are written to a transaction log when they are processed. Periodic "snapshots" are taken of the master file. when a problem is detected, the recovery manager program starts with the snapshot of the master file and reprocesses all transactions that have occurred since the snapshot was taken.