LR, CS5, NAS, OSX experiment requested

Started Oct 2, 2011 | Discussions thread
Mark K W Senior Member • Posts: 1,678
Re: LR, CS5, NAS, OSX experiment requested

Ross, I think it is down to how the networking file-access protocols work.

When you access the files locally, then that is direct through the Apple's disk filing system. It may well be that that file system allows mutiple apps to have the same file-open and do sequential read-writes, such that the file can be held open for reading in one app (e.g. LR3) and then also be being written in another (CS5). Hence there is no file-access collision between LR3 and CS5 when you operate locally. I think Macs use a file-system called HFS+.

When you access the files on a NAS, there is the local NAS filing system (such that the NAS's own processor can open and close the files, do the reading/writing, RAID redundancy striping, etc.,). Something like UFS may be used for this. Above that though is the protocol that the various computers use to access the files over your LAN. That is a higher-level file-access protocol (SMB is often used for this).

(You can Google all these file systems and protocols, but like I say I am not precise expert, I just understand the basics)

A higher-level file-access protocol will in essence allow read, write, delete, and the very basic primitive operations on a file. All need to be robust over a slow network, and in multi-user configurations.

Under those networked file-access design conditions, I can well imagine a file cannot be opened for writing in one application (in this case CS5) whilst being read in the other (LR3). Also I can believe that a file must be effectively be deleted before being overwritten with new data. This is what I think CS5 does on saving a networked file (this part is in all likelihood beyond CS5's control; it is happening at the OS/NAS file-system level).

I think all above will be behind why you/we are seeing what we are seeing. So - I think it's an outcome of network file-access behaviour, not a bug as such. By all means raise it to Adobe as a bug if you want, but I'd bet you'll get this kind of explanation.

Hope my deductions are helping rather than confusing!! Cheers, Mark W.

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