The idea of a restricted shell first arose in the Unix operating system in order to prevent the end-user from doing as many operations as a normal shell allows. A restricted shell lets the administrator control the end-user’s computing environment by only permitting explicitly used commands to be used. The Linux restricted shell (rssh) is similar, but only a minimum command set is enabled for the end-user. When installed, the default configuration is to remove all access and capabilities until the configuration file is modified by the admin. In the Read More

The NTOSKRNL.EXE is missing or corrupt error message is usually encountered during the boot process of NT based Windows operating systems. It can also be classified as a blue screen error, which is a colloquial term coined by users to describe error screens displayed by Windows. These errors are displayed due to critical system errors which may cause the system to shutdown to avoid system damage. This specific error may occur because of common hardware failure, the Ntoskrnl.exe file is missing or corrupt, Windows is not installed in the location Read More

ITSM stands for Information Technology Service Management. It is a discipline that is widely used for managing large, medium and small scale information technology systems. ITSM is targeted towards the customer and is considered a consumer friendly approach to managing a wide variety of services. ITSM tries to put the consumer relationship first, by switching the emphasis from an IT centered philosophy to a customer service philosophy. IT Service management is sometimes associated with other types of management philosophies including Six Sigma, TQM (Total Quality Management) and Business Process Management. Read More

An integer overflow, or integer wrapping, is a potential problem in a program based upon the fact that the value that can be held in a numeric datatype is limited by the data type’s size in bytes. ANSI C uses the following minimum sizes: data type size (bytes) char 1 short 2 int 2 long 4 In practice, many compilers use a 4-byte int. It also should be noted that the actual ranges for the data types depend on whether or not they are signed. for instance, a signed 2-byte Read More

Cell phone cloning refers to the act of copying the identity of one mobile telephone to another. This is usually done to make fraudulent telephone calls. The bill for the calls go to the legitimate subscriber. This made cloning very popular in areas with large immigrant populations, where the cost to “call home” was very steep. The cloner is also able to make effectively anonymous calls, which attracts another group of interested law breakers. Cell phone cloning started with Motorola “bag” phones and reached its peak in the mid 90’s Read More

Tip and Ring are telephony slang for the two wires which make up the electrical circuit used for telephone wiring. Tip is the nickname for the electrically positive wire and Ring is the nickname for the electrically negative wire. Tip is the ground side, which is positively charged, and Ring is the battery side, which is negatively charged, of a telephone circuit. The tip is synchronized with the office of the telephone company. Ring carries -48 volts of DC voltage when in an idle or on-hook condition. The grouping of Read More

DLP (Digital Light Processing) is a technology widely used for projecting images from a monitor onto a large screen for presentation purposes. A DMD (Digital Micromirror Device) is used to create sharp images which can be clearly noticed even in a normally lit room. Developed in the 1980s by Texas Instruments (TI), DLP became commercially available in the late 1990s. Texas Instruments remain the sole manufacturer of DLP technology. How DLP Works Before the development of DLP, most computer projection systems were based on LCD technology which tends to generate Read More

As its name suggests very clearly, laser engraving is the art of engraving or marking objects using one or multiple lasers. Considering the preciseness that is required with the engraving, the whole process is quite complex and technical, which often requires a computer. Therefore, as desired, the final engravings are done extremely precise at a very high rate. Most of the laser engraving done today is conducted by what is known as a laser engraving machine. This machine has three main parts to it: a laser, a surface, and a Read More

SQL (Structured Query Language) is the most common standardized database language used to create, retrieve, access, modify, controland manage relational databases. SQL is a querying language exclusively designed for controlling data and managing databases effectively. SQL was originally developed by IBM (International Business Machines Corporation) in the 1970's for their DB2 RDBMS. The team of developers included Andrew Richardson, Donald C. Messerly and Raymond F. Boyce. This first version was initially known as SEQUEL. It was basically used to modify and query the data stored in IBM's relational database product Read More

The F connector is a particular type of radio frequency connector that was developed in the early 1950’s. Eric Winston is usually credited with the creation of the F connector, while developing cable television as an alternative to the broadcast television options of the day. What does the F Connector do? The F connector provides an inexpensive connection for coaxial cables to communications devices and to other cables. While the cost of an F connector is generally less than many other types of radio frequency cable connectors, the connection provided Read More