tar (was: Re: Article on data rot on CD's)

From: der Mouse <mouse_at_Rodents.Montreal.QC.CA>
Date: Thu Jul 29 10:47:45 2004

>>> I laugh at those who criticized me for backing up my system with tar :)
>> it's funny, tar seems to be the one thing that still works, [...]
> Indeed. Doesn't tar have issues over 2GB archive sizes though,

No, though some implementations of tar do.

tar does have issues with individual files over 8G, I think it is; if
I'm reading this code right, the size field in the header is only 33
bits wide (11 octal digits).

> I'm not sure what the pathname length limit is for tar either

100 characters. Some versions of tar (mine, GNU) use various
extensions to effectively raise this limit; others break in various
ways on pathnames that exceed it - or, in particularly bad
implementations, approach it too closely.

I would really like to find a spec for the tar format. Everyone waves
hands and talks about this standard and that, but I've never actually
managed to track down a spec.

> Anyone got any pointers to a good site stating the different
> limitations of tar for different vendors / releases?

I don't know about a "site", but Elizabeth Zwicky, years ago, did a
lovely little paper called _Torture-testing Backup and Archive
Programs: Things You Ought to Know But Probably Would Rather Not_.
According to the (paper) copy I have, it was presented at LISA V in
1991. While some of the programs listed have doubtless had new
versions released in the more than a decade since then, others (such as
SunOS tar) which many classiccmpers are likely to be using haven't.

/~\ The ASCII der Mouse
\ / Ribbon Campaign
 X Against HTML mouse_at_rodents.montreal.qc.ca
/ \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B
Received on Thu Jul 29 2004 - 10:47:45 BST

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:36:53 BST