Archive for the ‘What Is A’ Category
Written By: pottersclay75
There are plenty of technical resources on the Web that discuss cyclic redundancy checks (CRCs). Most times you won’t need to worry about this technobabble. That is, until one it day it suddenly appears and you think – what the hell does that mean? In simple terms, a CRC is bit of mathematics used to ensure that your data is OK when being transfered. It’s a checking procedure that quickly identifies when data has been damaged. If you get this message, it means that the file being read by your PC or software is corrupted. However, it does not mean all the data is lost forever. When data is transfered, it is usually in small blocks and each block is given a CRC value. If something goes wrong with the data between the time it leaves the source and arrives at its destination, the CRC sent at the source will no longer match the one that is calculated when the data arrives – this is when the cyclic redundancy check error will appear.
The most common times you will see the cyclic redundancy check error message is when trying to read data from a damaged CD or DVD. Just before it appears, your CD/DVD drive will probably grind and whirl away – your PC may also become a little slugglish.
Less frequent causes are the result of system crashes, and buggy software (hello Microsoft), incomplete downloads (often identified by the misleading message ‘This is not a valid Windows file’, ‘This is not a valid win32 application’ or ‘Corrupt Zip file’). If this problem happens frequently with downloads, try using a download manager like GetRight. If you have lots of zip files on your system and want to check they are still valid, get a copy of CRC Checker – it’s free and can validate zip or rar files in batches – which is much easier than doing it one at a time. This program is worth downloading and keeping on hand for when problems strike.
For CDs and DVDs, the problem is a little different. Normally, when CD/DVD drives get a CRC message from a disc, they try to read the disc again – hence the grinding sound. After several failed attempts, they give up and display the redundancy check error. The problem can be hardware (loose cables, failing drive), software or damaged media. In most cases checking and cleaning the disc is the easiest way to overcome the problem. If different clean discs produce the same error, it is likely to be a hardware issue (check the discs in another drive). Another common cause of these errors is poorly burnt CDs and DVDs – especially those that had numerous or severe buffer underuns. USB burners suffer from this problem when the burn speed is too high (generally above 4X-8X)
If the discs are damaged, you’ll probably need a recovery tool to get back your data. CDCheck 3 will work for CDs and DVDs. First it will check the media, and then you have the option to recover the files. It’s free for personal use and has saved many people heartache when it comes to recovering lost digital images and videos from damaged CDs.
A computer cookie is a file that is created on your computer by a website to store information about a visitor. This can be to track which pages you look at on a site, to customize the way a page looks to you personally. They are used to store an encrypted version of your passwords, if you tick that box on website that says remember me that’s using a cookie! Technically its a java script that’s on a websites pages which is executed by your browser to write a file. They also have expiration dates (usually about 1 month for passwords) they also cannot usually be opened by other sites that is its only use able by the site that created it.
With America in the grips of the cold war scientists of the USA where given the task of building a spy satellite with the purpose of detecting the detonation of nuclear warheads. This system would pick up the tell tale gamma ray burst (GRB) produced by the detonation. When a nuclear weapon is detonated it produces alpha, beta and gamma radiation, gamma is the most penotrating hence the thickness of materials used in nuclear shelters to keep them out. Because of this they are an excellent way of detecting the testing of nuclear weapons.
This is a measurement of Quantum information like its BIT counterpart it would represent a 0 or a 1 however unlike a bit it exists in both states at the same time and can exhibit ‘quantum entanglement’.
“Entanglement is a nonlocal property that allows a set of qubits to express superpositions of different binary strings (01010 and 11111, for example) simultaneously. Such “quantum parallelism” is one of the keys to the potential power of quantum computation.” – WIKI
The name Quarks is a broad name for the following 6 types of quark
Up quarks – Up quarks are positively charged and carry a charge of +2/3 (plus two thirds).
Down quarks – Down quarks on the other hand have a charge of -1/3 (minus one third).
The following are broadly known as heavy quarks
Strange Quarks.
Charm Quarks.
Bottom Quarks.
Top Quarks.
Up/Down Quarks and Gluons are the basic building blocks of the atomic nucleus. It is unknown at the present time if a quark can be broken down into even smaller building blocks, as at the present time its impossible to isolate a quark for analysis.
Just when you thought Quantum mechanics couldnt get any weirder it does, Quantum Superposition describes the effect of a quantum unit being in multiple states at the same time. Such as a particle being in multiple positions at the same time. Check out this link for more information.
See also Superposition principle
Protons are positively charged particles in an atomic nucleus and Neutrons as their name suggests have a Neutral charge. Protons are made up of 2 Up Quarks and 1 Down Quark (+1 charge) joined together by three Gluons. Neutrons are made of 1 Up Quark and 2 Down Quarks (0 charge) and are also joined together by three Gluons.
What Is A Plank Length
A googol is 1 and then 100 zeros, it is the name given when manipulating vast numbers. A googleplex is a 1 with a googol number of zeros….
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