What is a holey file?

What is it? Why do they exist? Why I can't handle them as other files?
LVL 4
jlmsAsked:
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

x
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

EricKaplanCommented:
"holey" file ? are you sure you got that right ?

-Eric.
0
jlmsAuthor Commented:
I think so...
0
EricKaplanCommented:
Where did you get that info ? what OS ? ....
0
Become a Certified Penetration Testing Engineer

This CPTE Certified Penetration Testing Engineer course covers everything you need to know about becoming a Certified Penetration Testing Engineer. Career Path: Professional roles include Ethical Hackers, Security Consultants, System Administrators, and Chief Security Officers.

remboCommented:


When you talk about holey files, I'm assuming
that you're talking about files which were
creating with empty checks via lseek.  

These are stored in the filesystem using
only header info, not real disk blocks.  However,
if you try to put this on to a tape, especially
with dd or something like that, it will try to
write the actual blocks.  

For example, you could lseek forward 2GB in a file
and then write 1 character.  Your file size is then
huge, but it actually only takes up one disk block
(this is in UFS, not any old SVR4 system).  However,
older filesystems can figure this out.

Anyway, the deal is you need to be careful with things
that might try to map these headers to real data.

So, the deal is, try not to create holey files :)
but if you do, just know what you're doing with
them and how you move them.  Try to use tar and
modern, ufs or vxfs filesystems.  

If there's a specific application you're wondering
about, let me know.  I'd be happy to help.

-Tony


0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
jlmsAuthor Commented:
I think I understand, and no, I don't have any application in particular in mind.

One last thing, how can I recognize one of this files?
0
jlmsAuthor Commented:
I think I understand, and no, I don't have any application in particular in mind.

One last thing, how can I recognize one of this files?
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Unix OS

From novice to tech pro — start learning today.