Does a CD/DVD maintains a list of CRC of the files that it contains? It seems, the answer is NO. But that sounds so unbelievable for a archive media such as a CD/DVD. And if the answer is yes, where to find the CRC list?
2007-02-12 17:36:40 · 4 answers · asked by Sanjiv D 2 in Computers & Internet ➔ Programming & Design
Data CDs do actually use CRCs for error correction. The CRC is stored in the file table (commonly known as the TOC or table of contents). This data is not in a particular file. It's stored in the same place on the disc as the filenames and folder names.
If you've ever had a bad or scratched disc and tried to read a file off of it, I'm sure you've seen the message "Error: Cyclical Redundancy Check". This message is telling you that the data read doesn't match the CRC.
For archiving purposes, you might consider using the RAR format which not only includes hashes (to indicate if a file is damaged) but also repair info. WinRAR is a good program to use for this. You can make an archive that spans several discs where each part of the archive exactly fits the disc. You can also read files from a part of the archive (though only files that are in that part.)
Don't forget to include some program for reading rar files from the disc later on.
2007-02-12 17:51:51 · answer #1 · answered by Jack Schitt 3 · 0⤊ 0⤋
Well, the actual cd itself does not have a list of the crc files that it contains. Although Windows, as well as other programs do make their own CRCs on the fly and compare them to the transmitted data. This is quite common in online-based games to avoid cheating by using debugging tools or packet editors.
2007-02-12 17:43:34 · answer #2 · answered by venereal_madness 6 · 0⤊ 0⤋
attempt cleansing the CD. Use lukewarm water and cleansing soap with a mushy fabric and wipe it first. If it nonetheless doesnt artwork, then attempt coping the CD to a distinct CD. Your pc would have issues interpreting it, yet perchance a CD copier will actual replica the guidance properly. attempt it with new disc. If that doesnt artwork, then ask a technician who handles documents move which will be functional you move the guidance to a diverse CD. they're many times style of intense priced although. Thats why its scary to trust in a CD to do backups, if the CD receives corrupted, we are screwed. I in additional than a number of circumstances make 2 backup CD copies of each and every thing purely in case this happens.
2016-11-27 19:38:09 · answer #3 · answered by ? 4 · 0⤊ 0⤋
Depends how you burned it. Short answer, no, they don't.
2007-02-12 17:40:20 · answer #4 · answered by Anonymous · 0⤊ 0⤋