Re: Datafile recovery

In article <33748975.80037682_at_allnews.nb.sympatico.ca>, Doug Meredith <no_at_junk.mail> wrote:
>>Carefull with tar. It does compression and could lose some data eg repeating
>>null values.
>
>Actually, tar doesn't do compression. Even if it did, I don't see why
>there would be any risk of losing repeating null values.
>
>Don't worry about tar. It is tried and true.

Agreed, tar is about the best at shuttling large files around, and even moving them from one file system, to another and between machines using remote shells.

You are right about tar not doing any compression, but further any of the standard compression utilities like compress, pack and even my personal favorite gzip do not introduce any loss of data. If they did, they would be next to useless the way most people use them. These tools are pretty much standard for moving data across the internet in archived format.

Some implementations of tar do have some problems dealing with long absolute file names. I believe, but don't quote me on this, that some have problems with fully qualified file names linger than 56 bytes. Not sure of the exact number, but 56 seems to stick in my mind.

This would be a problem if there were some very long path names to data files and data file names. So, tar should be used with care in this instance.

However, tar, as far as I know, along with standard compression utilities is a very safe way to go under most circumstances. The previous poster should re-check his sources or the person who informed him that tar has problems.

Mike

-- 
Michael P. Sullivan                                           PP-ASMEL/IA
Aero-Vision Technologies, Inc.                             Skylane N52792
E-Mail: msullivan_at_ACM.org  or  mps_at_aero-vision.com    Phone: 516-952-3516
  * UNIX Systems and Database Consulting, Architecture and Management *