Portable Document Format (PDF) files are an ubiquitous way to package and share documents. The format was introduced in 1993 by Adobe Systems and remained a closed proprietary format (but free to use) until released as an open standard in 2008.
Upgradable electronics are capable of accepting additional or replacement hardware components to extend their functionality and lifespan. Highly upgradable electronics include such items as desktop computers, where in it is very simple to upgrade memory DIMMS, swap out hard drives, or otherwise improve the machine. Laptops are less upgradable as many of the components (such as the GPU) are integrated right into the machine and cannot be exchanged for a better model. On the opposite end of the spectrum are items like MP3 players and smart phones where there is no expectation in the consumer that the device will be upgradable in any fashion (and they are prepared to purchase a new unit when theirs is obsolete).
One of the first tasks given to a student studying a new programming language is to copy a simple program that outputs the phrase “Hello, World” on the screen. This classic exercise helps familiarize the students with the basic structure of the new language they are studying.
Virtual machines are a form of sandboxing wherein a computer and it’s operating system are simulated, via software, within the operating system of another computer. This concept is distinct from multi-boot systems wherein the user can boot the machine entirely into different operating systems using a boot manager.
An email signature, or signature block, is a block of text appended to the end of an email communication which usually contains the sender’s contact information (such as address, phone number, and social media contacts) as well as other information such as quotations, legal disclaimers, and other material.
In contrast with the Random Access Memory (RAM) modules found in most computers and other devices, Non-volatile memory has a unique property–it retains the data contained within it even when the power is turned off.
Random Access Memory (RAM) is found in everything from computers to tablets to smartphones and everything in between (including routers, cable modems, and other embedded electronics). RAM is a form of rapid access storage used by computers as an active workspace; it derives the “random” part of its name because the computer is able to access any individual data byte within the RAM at any given moment (by contrast, hard drives are read/written in entire blocks and thus not as quickly accessed as RAM modules).
Initialization files, or as they are more commonly known, INI files, are an artifact left over from earlier versions of Windows. Prior to Windows 95, Windows stored critical system variables in INI files (which were essentially just text documents with variable lists in them). Starting with Windows 95, all these settings were found in the Windows Registry system and Microsoft encouraged software developers to do the same.
Anti-aliasing is a technique used by to smooth the appearance of jagged lines in graphical images. When you turn on the font-smoothing functionality in your operating system or graphic design application, for example, you’re using anti-aliasing to make the edges of the lettering and GUI elements appear smoother.
A hot pixel is a pixel that, unlike a dead pixel, is not inactive but instead stuck on a single color and unresponsive to the attached computer’s commands. Users typically find hot pixels more annoying than dead pixels, as the hot pixel (often times white or a bright shade of color) is jarringly obvious on most displays.
A dead pixel is a pixel in a liquid crystal or other non-CRT display that no longer responds to input from the controlling computer and is incapable of displaying any colors. Dead pixels are typically either the result of a manufacturing defect (if present immediately from the time a device is unpackaged) or from physical damage to the screen (if they appear after the device has been in active use for a period of time).
Hybrid drives are a fusion of traditional hard drive technology (magnetic platters) and newer solid state drive technology (flash memory). In a typical hybrid drive design, the majority of the storage space is traditional magnetic media with an attached solid state component around 1-5% the storage capacity of the magnetic media. This small supplementary solid state drive is used as a very high speed cache for the larger drive—any recently accessed data is cached on the solid state portion of the hybrid drive to increase access speeds and decrease power usage.
A solid state drive (SSD) is an electronic storage medium that uses flash memory instead of magnetic platters to store data. Solid state drives have several advantages over traditional magnetic-media hard drives, including access speeds (reading and writing is instantaneous as the seek-on-disk action which is an element of platter-based disks has been removed) and power consumption (SSDs consume very little energy as they have no moving parts).
Revolutions Per Minute (RPM) is one speed measurement used to assess the performance of platter-based hard drives. The faster a drive platter spins, the faster the read/write assembly of the hard drive can access the data. Typical hard drive RPM values range from 5,400 (common in low-end drives as well as external drives where a low RPM value wouldn’t bottleneck performance) to 15,000 RPM (common in high-performance drives intended for gaming, video editing, and other disk-intensive applications).
The hard drive (or Hard Disk Drive, hence HDD) is the primary storage medium on most computers. Traditionally computer hard drives were (and largely still are) aluminum or glass platters impregnated with a ferro-magnetic material. Data is written, via a simple binary 0/1 system using the polarity of the particles, to the platters using a tiny read/write head attached to a small mechanical arm. Large capacity drives generally have multiple platters.
Like the Electronic Serial Number (ESN) and later Mobile Equipment Identifier (MEID) identify CDMA-band phones, the International Mobile Station Equipment Identity (IMEI) identifies GSM-band phones. Each IMEI number is unique to the device it is attached to and not directly linked to the user of the phone. Unlike the ESN/MEID system, wherein the cellular provider associates the number with the user and their access to the cellular network, the IMEI system relies on SIM cards or other identifying components to provide the International Mobile Subscriber Identity (IMSI) number. This is why GSM-band phone users can take the SIM card out of their phone (say, in the case of malfunction) and temporarily place it in their friend’s GSM phone in order to resume making phone calls using their own phone number.
Prior to 2005, CMDA cell phones (such as those used on the Sprint and Verizon networks) were identified by a 32-bit number known as an Electronic Serial Number. By 2005 the explosion of cellphone users had depleted the pool of ESNs so severely that a replacement was required. The MEID, with 56-bits, offers a much larger pool of numbers to pull from.
From the 1980s until 2005 (where it was superseded by the MEID format), mobile electronic devices were assigned a 32-bit number known as an Electronic Serial Number. This number was initially used with early cell phones and, later, predominantly with CDMA phones (such as those deployed by Sprint and Verizon). The ESN is usually represented by either an 11 digit decimal number or an 8 digit hexadecimal string.
A femtocell, commonly called a microcell, is an indoor cellular access point that uses internet access at its location of installation to route cellular calls over the internet. Femtocells are powerful enough to cover the area of a large home or small business (roughly 4-5,000 square feet) and benefit both the user and the cellular provider in that they provide a better signal for the end user and decrease the load on the cell provider’s tower system.
Gamification is the application of gaming principles to non-game environments, usually with the intention of increasing user engagement. Exercise programs that create game-like environments and achievement systems based on the amount and frequency of exercise, for example, have applied gaming principles to what would otherwise be regarded by most people as a mundane and unpleasant task.
The power transformers/adapters that many electronics require are, non-affectionately, referred to as wall warts. The unpleasant sounding term pokes fun at the adapters which are generally ugly, bulky, and quite frequently block nearby electrical sockets.
A hashtag is a means of attaching an easily understood and search-friendly identifier to instant messages, chats, tweets, and other searchable media. Hashtags are most commonly prefixed by the number sign and followed by a single entry (which may be a single word or multiple words condensed into one). For example, people discussing the Olympics on Twitter might tag their posts with #2014Olympics.
A guest account is an account on a computer system that has the lowest level of access privileges. While administrator accounts can make sweeping changes to the system and have complete access, and standard accounts are able to save data, launch applications, and otherwise maintain a user experience over time on the same machine, guest accounts are intended to allow temporary access to operating system for the purposes of light use including checking web-based email or otherwise utilizing the machine in a fashion which will make no permanent changes or save settings.