Knowledge of terms to know
What is Information System (IS)?
Information system (IS) refers to a collection of multiple pieces of equipment involved in the collection, processing, storage, and dissemination of information.
Hardware, software, computer system connections and information, information system users, and the system’s housing are all part of an IS. Personal computers, smartphones, databases, and networks are just some examples of information systems.
Enterprises and corporations use information systems to interact with their suppliers and customer base, perform their operations, manage their organization, and carry out their marketing campaigns.
They can be used for a broad variety of purposes, from managing supply chains to interacting with digital marketplaces. Individuals also rely on ISs to interact with peers and friends through social networks, carrying out everyday activities such as banking and shopping, or simply looking for knowledge and information.
What is IT Skills Gap ()?
In human resource management, an information technology (IT) skills gap is a mismatch between the technical knowledge an employer needs to meet business objectives and the capabilities of the organization’s employees.
Closing the IT skills gap by aligning the current state of workforce IT knowledge with forecasted future needs is a complicated proposition for C-level executives. Today, employers often struggle to locate and retain qualified tech talent, especially individuals with application development, security and data analysis skills.
Common approaches to closing an IT skills gap include recruitment process outsourcing, social recruiting, off-site training, employee mentor incentives, mentoring services, in-house turnkey training and partnerships with universities.
In many instances, an IT job will remain unfilled for an extended period of time when an employer needs to hire someone who has a very specific set of skills. In recruiting lingo, such candidates are referred to as purple squirrels. Because squirrels in the real world are not often purple, the implication is that finding the perfect job candidate with exactly the right qualifications, education and salary expectations can be a daunting – if not impossible — task.
What is Resolution?
Resolution is a measure used to describe the sharpness and clarity of an image or picture. It is often used as a metric for judging the quality of monitors, printers, digital images and various other hardware and software technologies.
The term is popular in the mobile industry for describing a mobile device’s display capabilities, and also in the entertainment media to distinguish the visual quality of movies to distinguish between high definition and standard definition movies. It is also used to determine the resolution of a screen, monitor, or TV.
Resolution is also referred to as screen resolution.
What is Physical Layer?
The physical layer is the first and lowest layer of the Open System Interconnection Model (OSI Model.)
The physical layer (also known as layer 1) deals with bit-level transmission between different devices and supports electrical or mechanical interfaces connecting to the physical medium for synchronized communication.
This layer plays with most of the network’s physical connections—wireless transmission, cabling, cabling standards and types, connectors and types, network interface cards, and more —as per network requirements.
The physical layer does not deal with the actual physical medium (like copper, fiber, etc.)
What is Load balancing?
Load balancing is a technique used to distribute workloads uniformly across servers or other compute resources to optimize network efficiency, reliability and capacity. Load balancing is performed by an appliance — either physical or virtual — that identifies in real time which server in a pool can best meet a given client request, while ensuring heavy network traffic doesn’t unduly overwhelm a single server.
In addition to maximizing network capacity and performance, load balancing provides failover. If one server fails, a load balancer immediately redirects its workloads to a backup server, thus mitigating the impact on end users.
Load balancing is usually categorized as supporting either Layer 4 or Layer 7. Layer 4 load balancers distribute traffic based on transport data, such as IP addresses and Transmission Control Protocol (TCP) port numbers. Layer 7 load-balancing devices make routing decisions based on application-level characteristics that include HTTP header information and the actual contents of the message, such as URLs and cookies. Layer 7 load balancers are more common, but Layer 4 load balancers remain popular, particularly in edge deployments.
What is Mobile Application (Mobile App)?
A mobile application, most commonly referred to as an app, is a type of application software designed to run on a mobile device, such as a smartphone or tablet computer. Mobile applications frequently serve to provide users with similar services to those accessed on PCs. Apps are generally small, individual software units with limited function. This use of app software was originally popularized by Apple Inc. and its App Store, which offers thousands of applications for the iPhone, iPad and iPod Touch.
A mobile application also may be known as an app, web app, online app, iPhone app or smartphone app.
Mobile applications are a move away from the integrated software systems generally found on PCs. Instead, each app provides limited and isolated functionality such as a game, calculator or mobile web browsing. Although applications may have avoided multitasking because of the limited hardware resources of the early mobile devices, their specificity is now part of their desirability because they allow consumers to hand-pick what their devices are able to do.
The simplest mobile apps take PC-based applications and port them to a mobile device. As mobile apps become more robust, this technique is somewhat lacking. A more sophisticated approach involves developing specifically for the mobile environment, taking advantage of both its limitations and advantages. For example, apps that use location-based features are inherently built from the ground up with an eye to mobile given that the user is not tied to a location, as on PC.
Apps are divided into two broad categories: native apps and web apps. Native apps are built for a specific mobile operating system, usually iOS or Android. Native apps enjoy better performance and a more finely-tuned user interface (UI), and usually need to pass a much stricter development and quality assurance process before they are released.
Web apps are used in HTML5 or CSS and require minimum device memory since they’re run through a browser. The user is redirected on a specific web page, and all information is saved on a server-based database. Web apps require a stable connection to be used.
There are several types of apps currently available.
- Gaming apps: The equivalent of computer video games, they are among the most popular types of apps. They account for one-third of all app downloads and three-fourths of all consumer spending.
- Productivity apps: These focus on improving business efficiency by easing various tasks such as sending emails, tracking work progress, booking hotels, and much more.
- Lifestyle and entertainment apps: Increasingly popular, these encompass many aspects of personal lifestyle and socialization such as dating, communicating on social media, as well as sharing (and watching) videos. Some of the most widely known apps such as Netflix, Facebook or TikTok fall into this category.
Other app types include mobile commerce (M-commerce) apps used to purchase goods online such as Amazon or eBay, travel apps that help a traveler in many ways (booking tours and tickets, finding their way through maps and geolocation, travel diaries, etc.), and utility apps such as health apps and barcode scanners.
What is Peripheral Device?
A peripheral device is an internal or external device that connects directly to a computer or other digital device but does not contribute to the computer’s primary function, such as computing. It helps end users access and use the functionalities of a computer.
Since it’s not a core device for the system, the computer can still function without the peripheral, which simply provides extra functions. However, some peripherals such as a mouse, keyboard, or monitor tend to be pretty much fundamental to the interaction between the user and the computer itself.
A peripheral device is also called a peripheral, computer peripheral, input-output device, or I/O device.
What is Cloud-to-Cloud Backup (C2C Backup)?
C2C backup (cloud-to-cloud backup) is the practice of copying data stored on one cloud service to another cloud service. The backup stored on the second cloud service serves the same purpose as an off-site backup.
Cloud-to-cloud backup is important for organizations that rely on software-as-a-service (SaaS) applications like Microsoft Office 365, Box and Zendesk. SaaS vendors back up their customers’ data, but any system can fail and restores can be difficult if the SaaS vendor’s backup software is fairly basic.
As more software applications are being delivered as services, there are an increasing number of vendors who are specializing in C2C backups for specific applications. In this scenario the C2C provider manages both the backup software and its implementation for the C2C customer.
What is vSAN?
A virtual storage area network (VSAN) is a logical partition in a physical storage area network (SAN). VSANs enable traffic to be isolated within specific portions of a storage area network, so if a problem occurs in one logical partition, it can be handled with a minimum of disruption to the rest of the network.
The use of multiple, isolated VSANs can also make a storage system easier to configure and scale out. Subscribers can be added or relocated without needing to change the physical layout.
A virtual SAN appliance enables unused storage capacity on virtual servers to be pooled and accessed by virtual servers as needed. A virtual SAN appliance is most often downloaded as a software program that runs on a virtual machine, but some storage hardware vendors are beginning to incorporate virtual SAN appliances into their firmware. Depending on the vendor, a virtual SAN appliance might also be called a software-defined storage (SDS) appliance or, simply, a virtual storage appliance.
The acronym for virtual SAN is spelled differently by different vendors. When spelled with all capital letters, the acronym is usually associated with Cisco Systems and is talked about in conjunction with zoning, which splits a physical SAN into multiple, isolated subnetworks. When spelled with a lower-case v, the acronym is usually associated with VMware and Hyper-V features that allow available hard disk drive storage to be pooled from across clustered hosts.
What is Cache Memory?
Cache memory is a small-sized type of volatile computer memory that provides high-speed data access to a processor and stores frequently used computer programs, applications and data.
A temporary storage of memory, cache makes data retrieving easier and more efficient. It is the fastest memory in a computer, and is typically integrated onto the motherboard and directly embedded in the processor or main random access memory (RAM).
Cache memory provides faster data storage and access by storing instances of programs and data routinely accessed by the processor. Thus, when a processor requests data that already has an instance in the cache memory, it does not need to go to the main memory or the hard disk to fetch the data.
Cache memory is the fastest memory available and acts as a buffer between RAM and the CPU. The processor checks whether a corresponding entry is available in the cache every time it needs to read or write a location, thus reducing the time required to access information from the main memory.
Hardware cache is also called processor cache, and is a physical component of the processor. Depending on how close it is to the processor core, can be primary or secondary cache memory, with primary cache memory directly integrated into (or closest to) the processor.
Speed depends on the proximity as well as the size of the cache itself. The more data can be stored into the cache, the quicker it operates, so chips with a smaller storage capacity tend to be slower even if it’s closer to the processor.
In addition to hardware-based cache, cache memory also can be a disk cache, where a reserved portion on a disk stores and provides access to frequently accessed data/applications from the disk. Whenever the processor accesses data for the first time, a copy is made into the cache.
When that data is accessed again, if a copy is available in the cache, that copy is accessed first so the speed and efficiency is increased. If it’s not available, then larger, more distant, and slower memories are accessed (such as the RAM or the hard disk).
Modern video cards also store their own cached memory inside their graphics processing chips. This way, their GPU can complete complex rendering operations more quickly without having to rely on the system’s RAM.
Other than hardware cache, software cache is also available as a method to store temporary files on the hard disk. This cache (also known as browser or application cache) is used to rapidly access previously stored files for the same reason: increasing speed. For example, an online browser might save some images from a web page by caching them to avoid re-downloading them every time that page is open again.
What is Workforce Planning?
Workforce planning is the strategic anticipation of labor requirements in order to deploy workers most effectively. Workforce planning is a subset of workforce management, an important component of most human resources and ERP (enterprise resource planning) software suites.
Workforce planning deals with broad-reaching issues that will affect the enterprise in years to come and can encompass all aspects of human capital management. Examples include the following:
- Forecasting “knowledge drain” as employees leave the organization;
- Anticipating future talent needs in response to changing technology;
- Determining and evaluating future sourcing options; and
- Establishing an effective workforce analytics strategy that dovetails with compliance regulations.
Some HR technology vendors, notably Kronos and Ceridian, have made workforce management and workforce planning software their main offerings. Infor and ADP also have workforce planning modules.
What is Internet service provider (ISP)?
An Internet service provider (ISP) is a company that provides customers with Internet access. It is often referred to as just “the provider.” Data may be transmitted using several technologies, including dial-up, DSL, cable modem, wireless or dedicated high-speed interconnects.
Typically, ISPs also provide their customers with the ability to communicate with one another by providing Internet email accounts, usually with numerous email addresses at the customer’s discretion.
Other services, such as telephone and television services, or personal websites or home pages may be provided as well. The services and service combinations may be unique to each ISP.
Today, ISPs are usually cable companies or mobile phone companies that offer Internet subscriptions in addition to TV or mobile communications services.
An Internet service provider is also known as an Internet access provider (IAP).
What is Command and Control（C&C0 server?
A command and control server (C&C server) is a computer that issues directives to digital devices that have been infected with rootkits or other types of malware, such as ransomware.
C&C servers can be used to create powerful networks of infected devices capable of carrying out distributed denial-of-service (DDoS) attacks, stealing data, deleting data or encrypting data in order to carry out an extortion scheme. A malicious network under a C&C server’s control is called a botnet and the network nodes that belong to the botnet are sometimes referred to as zombies.
In the early days of the internet, a C&C server was often under an attacker’s physical control and could remain active for several years. Today, C&C servers generally have a short shelf life; they often reside in legitimate cloud services and use automated domain generation algorithms (DGAs) to make it more difficult for law enforcement and malware hunters to locate them.
A C&C server may use multiple layers of misdirection and a variety of methods to establish and maintain network connections. The more challenging it is for a target to identify an infected system, the longer an attacker can maintain persistence on the target’s network. However, maintaining persistence doesn’t mean remaining undetected; rather, it means the attacker has more time to achieve goals.
Identifying anomalous network connections is key to identifying command and control servers, as few of them mimic human behavior — at least, for now. To that end, enterprises should keep a close eye on cloud services and collaboration services, such as Slack, Box, Dropbox and Salesforce, to plan an appropriate response if attackers abuse public cloud services.
What is Network Layer?
The network layer is a portion of online communications that allows for the connection and transfer of data packets between different devices or networks.
The network layer is the third level (Layer 3) of the Open Systems Interconnection Model (OSI Model) and the layer that provides data routing paths for network communication. Data is transferred to the receiving device in the form of packets via logical network paths in an ordered format controlled by the network layer.
Logical connection setup, data forwarding, routing and delivery error reporting are the network layer’s primary responsibilities. Layer 3 can be either able to support connection-oriented or connectionless networks (but not both of them at the same time).
What is Universal Serial Bus (USB)?
A Universal Serial Bus (USB) is a common interface that enables communication between devices and a host controller such as a personal computer (PC) or smartphone. It connects peripheral devices such as digital cameras, mice, keyboards, printers, scanners, media devices, external hard drives and flash drives. Because of its wide variety of uses, including support for electrical power, the USB has replaced a wide range of interfaces like the parallel and serial port.
A USB is intended to enhance plug-and-play and allow hot swapping. Plug-and-play enables the operating system (OS) to spontaneously configure and discover a new peripheral device without having to restart the computer. As well, hot swapping allows removal and replacement of a new peripheral without having to reboot.
There are several types of USB connectors. In the past the majority of USB cables were one of two types, type A and type B. The USB 2.0 standard is type A; it has a flat rectangle interface that inserts into a hub or USB host which transmits data and supplies power. A keyboard or mouse are common examples of a type A USB connector. A type B USB connector is square with slanted exterior corners. It is connected to an upstream port that uses a removable cable such as a printer. The type B connector also transmits data and supplies power. Some type B connectors do not have a data connection and are used only as a power connection.
Today, newer connectors have replaced old ones, such as the Mini-USB (or Mini-B), that has been abandoned in favor of the Micro-USB and USB-C cables. Micro-USB cables are usually used for charging and data transfer between smartphones, video game controllers, and some computer peripherals. Micro-USB are being slowly replaced by type-C connectors, which are becoming the new standard for Android smartphones and tablets.
A constructor is like an instance method that usually has the same name as the class, and can be used to set the values of the members of an object, either to default or to user-defined values. However, although it resembles it, a constructor is not a proper method since it doesn’t have a return type. Instead of performing a task by executing code, the constructor initializes the object, and it cannot be static, final, abstract, and synchronized.
What is Hybrid Cloud?
A hybrid cloud is a cloud computing environment that uses a mix of on-premises, private cloud and third-party, public cloud services with orchestration between these platforms. This typically involves a connection from an on-premises data center to a public cloud. The connection also can involve other private assets, including edge devices or other clouds.
What is Network Layer?
The network layer is a portion of online communications that allows for the connection and transfer of data packets between different devices or networks.
The network layer is the third level (Layer 3) of the Open Systems Interconnection Model (OSI Model) and the layer that provides data routing paths for network communication. Data is transferred to the receiving device in the form of packets via logical network paths in an ordered format controlled by the network layer.
Logical connection setup, data forwarding, routing and delivery error reporting are the network layer’s primary responsibilities. Layer 3 can be either able to support connection-oriented or connectionless networks (but not both of them at the same time).
The network layer is considered the backbone of the OSI Model. It selects and manages the best logical path (virtual circuit) for data transfer between nodes by assigning destination and source IP addresses to each data segment.
In the OSI model, the network layer responds to requests from the layer above it (transport layer) and issues requests to the layer below it (data link layer). Information about the source and destination hosts is already contained in the data link layer (Layer 2), but it’s the network layer that interconnects different networks allowing data to move between them. Quality of Service (QoS) allows for the prioritization of certain types of traffic.
Data is checked for errors by the Internet Control Message Protocol (ICMP), which ensures that packets are sent correctly by Layer 3.
Layer 3 contains hardware devices such as routers, bridges, firewalls and switches, but it actually creates a logical image of the most efficient communication route and implements it with a physical medium.
Network layer protocols exist in every host or router. The router examines the header fields of all the IP packets that pass through it. Networking software is used to attach the header to each data packet sent as well as to read it to determine how the packet is handled at the receiving end.
All the connection, encryption, checking, and routing processes occur at the network layer and are made by several different protocols, including:
- IP
- IPsec
- IPX/SPX
- ICMP
- IGMP
- GRE
Internet Protocol (IP) and Netware IPX/SPX are the most common protocols associated with the network layer.
The network layer infrastructure is inherently vulnerable to malicious attacks since it is exposed on the Internet. Distributed denial-of-service (DDoS) attacks can be launched to overwhelm all the physical network interfaces such as routers and stop data transmission.
Although this comparison can be misleading, the OSI network layer is often referenced as the equivalent of the Internet layer of the TCP/IP model. However, there are several differences between the two, and the TCP/IP Internet layer only has a limited amount of the functions covered by the OSI network layer.
What is Constructor?
A constructor is a special method of a class or structure in object-oriented programming that initializes a newly created object of that type. Whenever an object is created, the constructor is called automatically.
A constructor is like an instance method that usually has the same name as the class, and can be used to set the values of the members of an object, either to default or to user-defined values. However, although it resembles it, a constructor is not a proper method since it doesn’t have a return type. Instead of performing a task by executing code, the constructor initializes the object, and it cannot be static, final, abstract, and synchronized.