CRC32

Post questions here relative to DataStage Server Edition for such areas as Server job design, DS Basic, Routines, Job Sequences, etc.

Moderators: chulett, rschirm, roy

Post Reply
venkat n
Participant
Posts: 29
Joined: Fri Mar 18, 2005 3:28 am

CRC32

Post by venkat n »

What is CRC32?
On which situation we will go for CRC32?
how we will use CRC32?
Venkat Nagabhairu
EDS
kcbland
Participant
Posts: 5208
Joined: Wed Jan 15, 2003 8:56 am
Location: Lutz, FL
Contact:

Post by kcbland »

Please use the Search facility. You'd have your answers in detail with various discussions on its usage.
Kenneth Bland

Rank: Sempai
Belt: First degree black
Fight name: Captain Hook
Signature knockout: right upper cut followed by left hook
Signature submission: Crucifix combined with leg triangle
ArndW
Participant
Posts: 16318
Joined: Tue Nov 16, 2004 9:08 am
Location: Germany
Contact:

Post by ArndW »

Both Google and Yahoo! retrieve over 1.12 Million hits for the search phrase of CRC32!

Doing a cyclical redundancy check (CRC) on a text string or file will return a number - it used to be a 16 bit number but is now a 32 bit number. Changing just one byte of a file will result in the CRC32 result changing as well. This type of check was implemented for data transfers; it ensures (well, it tries to ensure) that a transmission was received exactly as it was transmitted by doing a CRC32 on both sides and comparing the result.

When one does change data detection it is often advisable to use a CRC32 algorithm. Let's take a table 1000 rows of 100 columns of Char(10). If you want to compare the old record with the new one, you would need to store 1Mb of old data. If you just save the CRC32 of the old record the storage required is much less at 32Kb!
Post Reply