What is recommended Open File Manager solution?

English Applications
#1

Howdy,

Wondering what is the recommended solution for Open File Management, the ability to access a file while it’s in use (by another process or application).

For those who’ve been around long enough, St Bernard Software once practically owned the market for PC Open File Management, then about 6 years or so ago Microsoft introduced VSS (Volume Shadow Copy) as an integrated feature of Windows.

For those who don’t know why something like Open File Management exists, you might notice for example that when one User has opened a file, the Operating System is supposed to put a lock on the file so that no one else can open the same file with anything more than Read Only permissions. This avoids the problem of contention should both Users try to save the file with different changes.

In this example, the Open File Manager is supposed to permit the file to be opened and possibly modified by multiple Users and according to a set of configurable rules permit versioning or access.

In particular, I’m exploring current Realtime Archiving solutions in OpenSuSE 11.3. So for instance an Open File Manager is required to support real time archiving of the running system because the OS will lock files during operation and ordinarly wouldn’t permit access by the archiving program. The OFM would be granted access and resolve running file change issues which would be inserted into the archive. The OFM should also track and do “write back” modifications to the real time archive as Users change files on the machine during the archiving process.

TIA,
Tony

#2

Don’t know if this will provide any help:
Orthodox File Managers: Home of the OFM standard

#3

Thx for the try but not relevant.
The author of that website coined his own term for OFM (Orthodox File Manager) suggesting a common UI for file managers.

But, he doesn’t mention any Open File Managers as products or plugins anywhere.

Tony

#4

I may have found the answer… in Wikipedia

File Locking

Apparently according to the article *NIX fs usually only considers file locks “advisory” and even then there are ample ways typically for code to circumvent even “mandatory” locks.

Hmmm. Maybe more a Development type issue, but this raises all sorts of questions in my mind regarding file consistency and enforcing transactional changes. If locks aren’t enforced it seems to me that a functional system relies on every application behaving in a trusted manner and that serious coding mistakes don’t exist (some Pollyanna world).

Tony

#5

File locking is a difficult issue for OSes. You can create process deadlocks if you have hard enforcement. Usual solution is to interpose a manager process through which access goes. This is the approach taken by DBMSes. You could do something similar for your problem.