Commodity computing is a form of parallel computing. Unlike supercomputer setups that feature custom built hardware, commodity computing uses off-the-shelf hardware and computers to minimize costs. Companies use commodity computing because the cost of entry is low, parts are easy to replace, software and drivers are readily available, and the computers share a base architecture (such as Intel x86 or x64).
Parallel computing is a form of computation in which a large number of calculations are carried out simultaneously on hardware run in parallel. Parallel computation allows for some calculations and processes to be performed faster than serial computations (wherein each command must finish before the next is executed).
In modern email clients, both browser-based and stand-alone, you’ll find the digital answer to analog address books: contact lists. The most basic contact lists simply contain the name of the contact and their email address, but more robust contact lasts (such as those found in Outlook and Gmail) hold significantly more information like your contact’s physical mailing address, phone numbers, and other relevant information, including notes.
In computing, a black list is a list of items that a security algorithm or filter will always block. If you set up a filter in your email client to explicitly block the address of someone spamming you, for example, you’ve created a simple black list. Other black lists are automated, such as a black list that bans IP addresses at the server level after too many intrusion attempts are discovered from that IP address. Black lists are also used to filter content; when companies block entertainment or adult-content websites, they’re using a black list to restrict employee internet access.
In computing, a white list is a list of items that a security algorithm or filter will always allow to pass through. In the case of email, whitelisting an email address (typically done by adding it to your contact list) ensures that the email is delivered to your inbox. When configuring a firewall, the list of applications that are allowed to always pass through the firewall is the white list. White lists are useful as they allow administrators and users to ensure critical information and applications remain deliverable/functional even if changes are made to the security algorithms.
Every email has an email header. The header of the email contains information recipients are used to seeing with each email (the date it was sent, who it is from, and the subject) as well as a large amount of additional information that email clients hide from the user by default. The hidden information (typically accessible by looking for a “view full header” or equivalent button or link in your email client) includes the routing information for the email such as the address of each mail server it passed through and the times at which the email was passed forward.
Fingerprinting is an advanced form of spam prevention deployed at the server/provider level. The algorithms work in two primary ways: email body fingerprinting and email attachment fingerprinting. The pattern of language, links, and other content in the body of a spam email can be used to create a fingerprint that is used to analyze other future spam emails and prevent the spam for arriving in your inbox. Fingerprint algorithms are also used to analyze the content of attachments to detect malicious files (including those that have had their names and extensions changed from previously observed files).
Listserv was one of the earliest and most influential electronic mailing list applications. Released in 1986, the application is still going strong and in wide use around the world. Listserv introduced a wide variety of email list management features we take for granted today, such as automated subscribing and unsubscribing without the intervention of a human list curator, message templates, and spam filtering.
An electronic mailing list is a method of using email that allows for easy and widespread distribution of information to members of the list. There are two common forms of electronic mailing lists: distribution lists and announcement lists.
The junk folder (also known as the spam folder) is a folder found in the inboxes of most modern email services where emails that have not been outright rejected by the email provider’s global spam filters, but which appear suspicious (because they, for example, contain marketing terms and the sender is not in the recipients address book or address whitelist), are dumped for further review. This is why companies will frequently request you check your junk folder for emails that you have reported as unreceived, as legitimate commercial communications can often end up accidentally caught in the spam-hunting algorithms.
A bounce message is a form of auto-response sent to the sender of an email when the email cannot be delivered to the intended recipient. Although informally referred to as a bounce message, the message is technically known as a Non-Delivery Report (NDR). The message typically contains the date and time the original email was bounced, the identity of the mail server it bounced at, the reason for the bounce (e.g. mailbox full, user unknown, etc.), the headers of the bounced message, and a full or partial reprint of the original bounced message.
Email autoresponders are computer programs that automatically answer email. Autoresponders fall into two categories: infrastructure and user-definable. Infrastructure-based autoresponders are the responders that send you helpful automated messages like those you received when an email sent to a given domain cannot be delivered. User-definable responders most typically take the form of vacation away messages that indicate to the sender that the recipient is out of the office for an extended period of time. Other common user-defined responders include automated messages received after joining mailing lists or confirmation of a purchase made.
A spider trap is a web page or set of pages that traps any web crawler/search bot that comes across it. While some spider traps are unintentionally created (e.g. there is an element on the page such as a dynamic calendar with, essentially, infinite forward links for the crawler to follow), many spider traps are created with the intent of trapping spam crawlers looking for email addresses and other personal information. The heart of the trap, whether intentionally or unintentionally created, is series of links or a dynamic link system that a crawler gets stuck following (like a maze with no exit).
Email harvesting is the process of amassing lists of email addresses, almost always to spam them, using disreputable practices such as purchasing email lists in bulk from resellers, using giveaway/contest websites to harvest emails, or using harvesting bots to crawl web pages, forum and usenet posts, and other publicly accessible locations, looking for email addresses to add to the list.
An email attachment is a file sent along with the email message. Early email systems required manual attachment encoding in wherein the user would have to use a program to convert the file into a block of text which could be pasted into the body of the email. Such attachments were terribly inconvenient and required that the recipient know how to turn the block of encoded text back into whatever it was (picture, spreadsheet, etc.)
In email composition, the “BCC:” section, short for Blind Carbon Copy, is a method of sending an email to additional addressees without alerting the primary addressees (and the potential secondary addresses in the “CC:” section) that the email has been shared beyond those listed on the email. The practice is a holdover from the days of paper letters and memos where a document within an organization would be intended for a specific recipient but could also have additional recipients (including those whose identity, for whatever purpose, needed to remain hidden from the other recipients).
In email composition, the “CC:” section, short for Carbon Copy, is a method of sending an email to additional addressees without inserting them into the primary “To:” section. While this might seem counter intuitive as it’s just as easy to put an email address in the “To:” section as the “CC:”, the practice is a holdover from the days of paper letters and memos where a document within an organization would be intended for a specific recipient but additional carbon copies could be sent to people who needed to stay abreast of the material. That same functionality remains in email: the primary recipient(s) go in the “To:” section and anyone else who needs to be aware of the communication but is not the primary recipient goes in the “CC:” section.
Email obfuscation is an attempt to make an email address difficult for spam bots to harvest and begin spamming. There are two forms of obfuscation: manual obfuscation and HTML-code obfuscation. In manual obfuscation, the user manually breaks up their email address using text that a human can easily read and decode but that wouldn’t form a valid address a spam bot could harvest. Thus, an email address like firstname.lastname@example.org might be written like someguy AT somehost DOT org; a human could read that but it wouldn’t register as an email address if a bot was scanning for a typical *@*.* email address format.
Biometrics refers to the technology (both hardware and software) used to identify individuals based on their physical characteristics. Fingerprint scanners, facial recognition, and voice analysis are all methods of turning the user’s physical characteristics into security checks.
In computer security slang, a “black hat” is a malicious computer hacker. Unlike their counterpart, the “white hat” hacker, black hats are those who would exploit security flaws for personal gain (or for the benefit of the corporation, organization, or nation state they work for).
In computer security slang, a “White Hat” is an ethical hacker. The term white hat is applied to individuals that seek out security flaws and then notify organizations so the security flaws can be remedied as well as hired security specialists who look over an organization’s infrastructure to find the security flaws before malicious users do.
In computer security, honeypots, like their real-world counterparts employed by law enforcement agencies, are traps set to detect or counteract authorized access to computer networks. Honeypots can take the form of individual computers, data sets, or network sites that appear to be valuable or worth investigating to the intruding party but which are actually designed to entrap and/or monitor the attacker.
Digital preservation is a form of data backup focused on ensuring continued future access to the digital information preserved by the backup process. Whereas a typical backup system is designed to simply duplicate the data so that it may be restored in the event the original data set or host computer is damaged, groups concerned with digital preservation are not just concerned with creating redundant copies of data but ensuring that future generations will be able to access that data.
A differential backup system backs up the changes made to a system between the initial backup and the current backup. Unlike an incremental backup system, wherein only the newest changes from the previous increment are recorded, the differential system backs up everything that has changed from the initial backup on each subsequent backup. One way to visualize this is to think of incremental backup data sets, where A is the initial backup, as A + B + C + D, whereas differential backups are A + B + BC + BCD.