CRC error

Cyclic Redundancy Check this is the real name that lies behind the 3 letter acronym CRC. The usage of CRC varies from place to place. This is because only the name is alone standard and the backend algorithm can be coded and implemented for any purpose. The first and foremost reason for CRC is error detection.

When the spot light is thrown on this error detection it is further classified in to two divisions. Cyclic Redundancy Check used for detecting and reducing the transmission errors in the data i.e. In networking data need to be transferred over a wide range among various devices. At that time there are several chances for data being lost during the transmission. To monitor this, sender of that data attached some additional values with the original data and then transmitted it. The additional data is nothing but some polynomial division of a common number. The receiver will use the received data as well as the additional value in reverse process to check whether there is a data loss in the received data or not.

Another place where Cyclic Redundancy Check mechanism is used effectively is data storage in storage drives. Though the data inside a storage drive looks like normal files and folder, they are just a combination of tons of bit and byte binary values. When a data is created in the hard drive, in the upper level it will look like filesystem, files, folders etc. in the low level it will be just zeros and one’s that are filled inside a set of hash tables. Since even a single small file can hold lots of binary valued zeros and ones there are chances of data mislay and data loss. A loss of single value can alter the internal arrangement of a file completely in the raw level.

So a legitimate and resourceful mechanism is needed to look for data loss trails in the hard drive raw data. This is where Cyclic Redundancy Check is employed. Since the data is written in high speed, it will be scattered and stored in different locations of the HDD wherever there is possible space. The index of the scattered data will be created and stored in another part of memory. Along with this a few additional data that are calculated through CRC is also saved.

Whenever a file is clicked by the user in the hard drive, a Cyclic Redundancy Check will be undergone that all the needed data value store din the index file are available for processing or not. Suppose if there is a mismatch in the generated and verified CRC. Then definitely there is data loss. And the OS will indicate errors message like this.

“File open error: invalid CRC”

“Cannot copy file: Data error (Cyclic Redundancy Check)”

“CRC error: The file which you are running may be corrupted.”

If you ever find CRC in your error message, then alarm yourself that the data in the HDD is corrupted.

Advantages:

• This is just a simple code and can be produced and implemented in any form of applications.
• Easy to view single bit errors and multiple burst errors.
• Based on the severity and complexity of the error the error correction mechanism can be generated. This type of mechanism is commonly found in file repairing software and utilities.
• Because of its simplicity it can fit any type of operating system and all versions, including the latest.

Disadvantages:

• Though the Cyclic Redundancy Check look like an authentication mechanism, it is non trivial and easy to crack mechanism. It is not suitable for security purpose.
• Without the error correcting mechanism using CRC alone will be a useless thing.

To know how to repair CRC error in RAR file, just go through this page.