Definition

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Sunday, November 23, 2014

Définition ANSI ( American National Standart Institute )

Stands for "American National Standards Institute." ANSI is a non-profit organization based in the United States that works to develop and promote standards in the United States and around the world. By standardizing new products and technologies, both ANSI strengthens the US position on the world market and helps ensure the integrity and safety of products.

ANSI was originally called the "American Technical Standards Committee" (AESC), which was formed in 1918 AESC has worked with the American Institute of Electrical Engineers (IEEE now) and several other organizations to develop standards engineering. In 1928, the AESC was reorganized and renamed the "American Standards Association" (ASA). The ASA started developing partnerships with global organizations such as ISO and helped promote American standards in abroad. in 1969, the ASA was renamed to the ANSI standard. for decades, ANSI continued to promote national and international standards.

By standardizing new technologies, ANSI helps companies and government agencies to create products and services compatible. For example, when ANSI normalizes a specific type of hardwareport, computer manufacturers can build machines with standard port and know that it will be compatible with third-party devices. When ANSI standardized file format, software developers can support the format in their programs because the format information is publicly available.

When a new standard is accredited by ANSI, this means that the standard meets the requirements of the organization in terms of transparency, balance and consensus. In other words, only the standards that meet a process due to rigorous approval guidelines become accredited standards. This ensures that all accredited by ANSI standards apply to manufacturers and consumers.

Additional information on the ANSI standard can be found on the official website of the ANSI standard.

Définition ARP ( Address Resolution Protocol )

Stands for "Address Resolution Protocol". ARP is a protocol used to map an IP address to a computer connected to a LAN. Since each computer has a unique physical address called MAC address, ARP translates IP address to the MAC address. This ensures that each computer has a unique network identification.

The Address Resolution Protocol is used when the information sent to the network arrives at the gateway, which serves as the network entry point. The gateway uses ARP to find the computer's MAC address based on the IP address, the data is sent. The ARP typically considers this information in a table called "ARP cache." If the address is found, the information is transmitted to the gateway, which will send the incoming data to the appropriate machine. It can also convert the data to correct network format if necessary.

If the address is not found, the ARP broadcasts a "request packet" to other machines on the network to see if the IP address belongs to a device that is not in the ARP cache. If a system is valid, the information will be forwarded to the gateway and the ARP cache will be updated with the new information. by updating the ARP cache, future requests for that IP address will be much faster. While this may seem as a complex process, it usually only takes a split second to complete. If only it were that easy to find old recipes where you need it

Définition ASCII

Stands for "ASCII." ASCII character encoding provides a standard way to represent characters by using numeric codes. These include uppercase English letters and lowercase letters, numbers and punctuation symbols.

ASCII uses 7 bits to represent each character. For example, a capital "T" is represented by the number 84 and a lower case "t" is represented by 116. Other keys are also mapped to the standard ASCII values. For example, the Escape (ESC) is represented by 27 and the Delete key (LED) is represented as 32 ASCII codes can also be displayed as hexadecimal values instead of decimal numbers listed above. For example, the ASCII value of the Esc key in hex is "1B" and the hex value of the delete key is "7F".

Since ASCII uses 7 bits, it only supports 2 ^ 7, or 128 values. Therefore, the standard ASCII characters is limited to 128 characters. While this is sufficient to represent all the letters, numbers and standard English punctuation, it is not enough to represent all special characters or characters from other languages. Even ASCII, which supports the values of 8-bit or 256 characters, does not include enough characters to accurately represent all languages. Therefore, other character sets, such as Latin-1 (ISO-8859-1), UTF-8 and UTF-16 are commonly used for documents and Web pages that require other characters.

Tuesday, November 4, 2014

Définition Biometrics

Biometrics refers to technologies used to detect and recognize human physical characteristics. In the world of computing, biometrics is often synonymous with "biometric authentication", a type of security clearance based on the biometric input.

There are several types of biometric authentication. Common examples include the scanning of fingerprints, retina scan, facial recognition and voice analysis. Facial recognition system, for example, uses a camera to capture an image of a person's face. The photograph is then recorded and processed using software biometrics. The software tries to match the scanned image with an image from a database of user photos. If the analysis is close enough to a specific user, the person will be allowed to continue.

In many cases, a biometric scan is similar to a connection. For example, some computers have a fingerprint reader that allows you to authenticate by swiping your finger on a sensor. Instead of entering a username and password, the finger scan provides your permission. Some retail outlets are now using handheld scanners to check the identity of persons as an alternative to entering a unique identification number. High security government buildings and offices may even require retinal scans to access certain areas of the building. In some cases, an access card, password or login is required in addition to a biometric analysis to provide additional security

Définition Boot Sector

The boot sector is a dedicated hard drive or other storage device containing the data used to start a computer system section. It includes the Master Boot Record (MBR), which is accessible during the boot sequence.

The boot sector is usually located at the beginning of a disc before the first partition. It includes the separation plan, which identifies all the partitions on the disk. It also defines the partition that contains the starting data (such as the operating system). This allows the computer knows how to access at boot partition. Therefore, if the boot sector of a disk becomes corrupted or contains invalid data, the computer may not be able to boot from the disc. If this happens, you must run a disk utility or antivirus to try to solve the problem.

Définition Boot Sequence

Whenever a computer starts up, it goes through a series of processes first. This sequence of events is called a "boot sequence." During the startup sequence, the computer activates the necessary hardware and loads the appropriate software so that the user can interact with the machine.

The boot sequence begins with access to the BIOS of the computer on Windows PC or a Macintosh system ROM. BIOS ROM and contain basic instructions that tell the computer how to start. These instructions are then transmitted to the central processing unit of the computer, which begins to load information into the system RAM. Once the boot disk or valid boot disk is found, the computer begins to load the operating system in the system memory. After the operating system finishes loading, the computer is ready to use.

The startup sequence may last from a few seconds to several minutes, depending on the configuration of the computer. If the system boots from a CD or DVD, the startup time can be significantly longer if the computer is booted from a hard disk. Also, if your computer has been turned off unexpectedly, the start time may increase as the system can perform additional checks to make sure everything is OK.

Monday, November 3, 2014

Definition Cache

Cache, pronounced "cash" (not "catch" or "cashay") stores recently used the information to make it readily available at a later date. Computers integrate several types of caching to run more effectively, thereby improving performance. common types of caches include browser cache, disk cache, cache, and processor cache.

1. Browser Cache - Most data from the Web page web browsers default cache. For example, when you visit a web page, the browser can cache the code
HTML, images, and any CSS or JavaScript files referenced by the page. When you browse to other pages that use the same images, CSS or JavaScript, your browser will not have to re-download the files. Instead, the browser can simply load from the cache, which is stored on your local hard drive.

2. Cache - When an application is running, it may cache some data in system memory, or RAM. For example, if you work on a video project, the video editor can upload video clips and audio tracks on the hard disk into RAM. Since RAM can be accessed much faster than a hard disk, which reduces delay when importing and editing files.

3. Disk Cache - Most hard drives and SSDs include a small amount of RAM used for disk cache. A typical disk cache for a hard drive 1 terabyte is 32 megabytes, while a 2TB hard drive may have a cache of 64 MB RAM This small amount can make a big difference in performance of the car. For example, when you open a folder with many files, references to files can be automatically stored in the disk cache. The next time you open the folder, file list can instantly load instead of taking a few seconds to appear.

4. Cache CPU - CPU caches are even smaller than disk caches. This is because the processor cache contains tiny blocks of data, such as frequently used instructions, that can be quickly accessed by the CPU. Modern processors often contain an L1 cache that is right next to the processor and L2 cache which is a little further. The L1 cache is the smallest (about 64 Kb), while the L2 cache may be about 2 MB in size. Some high-end processors even include an L3 cache, which is larger than the L2 cache. When a processor accesses data from a higher level cache, it can also move data to the lower level cache for faster access next time.

Most cover is done in the background, so you will not even notice it happening. In fact, the only caches above you can control is the browser cache. You can open your browser preferences to display the cache settings and change the size of the cache of your browser or clear the cache if necessary.

Definition CDMA

Stands for "Code Division Multiple Access." CDMA is a wireless transmission technology that was developed during World War II by English allies to avoid having their scrambled transmissions. After the war, Qualcomm patented technology and commercially available as a digital cellular technology. Now CDMA is a popular method of communication used by many cell phone companies.

Unlike GSM and TDMA, CDMA transmits on all available frequencies. It does not affect an individual user's communication network frequency. This method, called multiplexing, which is difficult to jam transmissions during World War II. Because CDMA does not limit the frequency range of each user, it is more bandwidth available. This allows multiple users to communicate over the same network at the same time so that each user is assigned a specific frequency interval.

Because CDMA is a digital technology, the analog audio signals must be digitized before being transmitted over the network. CDMA is used by the 2G and 3G wireless communications and typically present in the frequency range from 800 MHz to 1.9 GHz wireless.