Spoofing is the process by which a computer is misrepresented on the network as another computer. Spoofing can be done at the hardware level (e.g. MAC address spoofing) or at the TCP/IP level (e.g. IP address spoofing). The primary purpose of spoofing is to allow the unauthorized computer to gain access to a secure network wherein the security is provided by verification of a hardware or IP address. If a Wi-Fi node is locked down to only specific pre-approved MAC addressed, for example, a malicious user seeking to gain entry would need to spoof a valid MAC address to connect to the node.
Data modification is a typical component of network-based computer attacks. Either the data transmitted by the local computer or transmitted back from the remote computer is altered in some fashion. Strong encryption between the local computer and remote computer ensures that the data remains unobserved or altered.
In network security, sniffing is the act of examining network traffic. This is the digital equivalent of eavesdropping on a conversation or telephone call; all unencrypted traffic on the network is visible to anyone with access to the network and appropriate tools to examine the packets of data passing by.
Fault Tolerant Computing is a sub-division of computer design and construction focused on building computer systems that are highly resistant to failure. Such systems typically have redundant and compartmentalized hardware system so that in the event of any hardware failure the system may either be 1) kept online or 2) be shut down gracefully.
In computing, a heartbeat is a tiny exchange between computers, typically used in a server environment where stability and uptime are critical, that checks to make sure all systems on the heartbeat network are available and operational. The operation is called a heartbeat because the exchange happens twice per second and mirrors the regularity of a beating heart.
FLOPS, or FLoating point Operations Per Second, is a measurement of floating point calculations. This measurement is typically used to reference the performance of super computers as it is a better indicator of the performance and computing power of super computer array than referencing the collective processing power of the array. Thus you’ll frequently hear a super computer discussed in terms like 100 teraflops (100 trillion FLOPS) instead of the speed of the processor like one references when talking about desktop and mobile computers.
Name resolution is the process by which human-readable locators are converted into machine-usable locators used by computer networks, databases, and other machine-based applications. Every time you type www.howtogeek.com, for example, into your web browser, you are initiating a name resolution wherein the human-readable address for How-To Geek is translated, via DNS servers, into the IP address of the How-To Geek servers.
Before centralized DNS servers, computers used a local text document, known as a HOSTS file, as a reference to link IP addresses to domain names. Although HOSTS files are no longer used as a primary domain reference, they are still included in operating systems as a way of locally manipulating the IP-to-domain resolution chain for various purposes like testing software.
A file viewer is an application designed to quickly view a file without requiring the user to open up the file in the application the file was originally created in. A common example of this arrangement is that of digital image files such as JPEGs–the vast majority of JPEG image files are opened in a file viewer of some sort and not in the application which originally created or altered the digital image.
File types are broad classes of digital files categorized by their general type. The document file type, for example, encompasses Rich Text documents, basic text files, and files created by Microsoft Word. The file type is different from an extension in that the extension describes the specific kind of file (e.g. a .RTF) and the type describes the class (e.g. document).
MPEG (Moving Pictures Expert Group) is a family of video compression standards that encompasses everything from DVD encoding to satellite video transmission. DVDs, for example, are encoded in MPEG-2, where as more modern HD video sources are encoded using MPEG-4.
H.264 is a popular video compression standard based on MPEG-4. It is widely used for both HD video sources like Blu-Ray discs and for streaming video from sites like YouTube using minimal bandwidth while maintaining quality video. While there other other H.X compression standards (like H.263), none have achieved the same level of widespread adoption as H.264.
The UHF (Ultra High Frequency) spectrum, or 700Mhz communication spectrum (technically 698-806Mhz), was historically used for television broadcasting. Starting in 2008, the FCC began auctioning off sections of the spectrum in anticipation of the 2009 switch from analog to digital TV broadcasts. Thanks to the suitability of 700Mhz spectrum broadcasts for long distance wireless communication, a significant portion of the available blocks were purchased by large telecommunication companies like Verizon Wireless and AT&T.
A thin client is a lightweight machine that offloads its processing and data handling tasks to a central machine. Under the thin client computing model, each thin client terminal the user interacts with is essentially just a front end that only handles rendering a local GUI for the user, while the actual computing happens on a central server somewhere else within the building or even in a remote location. While thin client computing has the obvious disadvantage of removing the actual processing power from the local machine, it has many advantages like ease of system maintenance, increased security, and, in some applications, significant cost savings over deploying a large network of more advanced PCs.
Within the designated Wi-Fi bands, such as the 2.4Ghz band, there are specific channels Wi-Fi access points may use. Although there are 14 available channels in the 2.4GHz band, each individual channel has a spread of approximately 22Mhz, which significantly overlaps surrounding channels. As such, multiple devices set to adjacent channels in a small physical space (such as an apartment block) will interfere with each other. For example, if you are having problems with Wi-Fi connectivity and sustained data transmission through your Wi-Fi router, it is recommended to check the operating channels of all detectable Wi-Fi access points to ensure your Wi-Fi access point isn’t operating on the same or adjacent channel as nearby access points. You can read more about identifying and changing your Wi-Fi channel here.
A portion of the wireless communication spectrum is dedicated to wireless local area network (WLAN or Wi-Fi). Within this dedicated portion of the spectrum there are four distinct frequency bands, as specified by wireless networking standard IEEE 802.11: 2.4 GHz, 3.6 GHz, 4.9 GHz, and 5 GHz.
Turn-based strategy games are computer games wherein humans (and computer opponents) complete their actions on set turns. The popular game franchise Civilization is an example of such a game style; players are allowed a period of analysis and decision making before committing to actions. The phrase “turn-based strategy” is used to distinguish games from the more common real-time strategy games where there is no downtime for analysis.
Real-time strategy games are video games wherein the action occurs in real time and all players must react on the fly to changes in the game with no downtime for game analysis and decision making. The Command and Conquer and StarCraft game franchises are both examples of popular real-time strategy games.
A sandbox, in computing terms, is a secure space where programs can be tested and code can be contained. In gaming, however, a sandbox refers to a game designed to be open and non-linear in nature so that the player may roam freely and interact with the environment more liberally than in a linear game where the action progresses from one level to the next.
A sandbox is a restricted environment that contains the actions and effects of the sandboxed software within it. For example, a user might opt to run a web browser through sandbox software so that any attempt made by a malicious web site or poorly written code to install software or otherwise affect the operating system or files on the greater computer would be stopped.
Half-duplex means that a given medium is incapable of transmitting and receiving over the same channel simultaneously. Walkie-talkies and push-to-talk cellular services are examples of half-duplex communication in action; one party can transmit communication to the other party but the receiving party must wait for the transmission to end before replying.
Full-duplex means that a given medium is capable of transmitting and receiving over the same channel simultaneously. A telephone call is an example of a simple full-duplex communication: both parties can talk simultaneously as telephony technology is configured such that the line can transmit the audio in both directions at the same time.
Shadow Copy, also known as Volume Snapshot Service, is a data backup technology included in Microsoft Windows that allows the operating system to take snapshots of the system which include files which are locked or otherwise inaccessible to the user. The service can only be used on NTFS-based disks and interacts with the data at the block level.
System Restore is a utility included in Windows since the release of Windows Me. The System Restore utility takes snapshots of the system including the state of the Windows registry, installed applications, system files, and system settings. These snapshots, or Restore Points, can be used to roll the system back to a previous state in the event that system changes (updating Windows, upgrading drivers, etc.) render the computer unusable or unstable.