Open read only turns into actual live drawing

[Steve_Bennett]

I don't really know how to title this one. It's the strangest thing I've seen happen in a while and it is something that goes against every bit of logic I can think of. Here goes:

Computer A opens drawing1.dwg on the local server and keeps it open.
Computer B opens drawing1.dwg on the local server while computer A has it open still.
While computer B is in the process of opening the file, computer A tries to save the file. When hitting the save button, computer A gets a message stating that the file is now locked for use and no longer able to save. In the meantime computer B opens the file just fine and receives no warnings that it is opening a read only file - it just simply opens the file as if computer A never had it open in the first place. It's as if the permissions for the file are switched from computer A to computer B with no one knowing about it until it is too late. This happens whether it is over the LAN or WAN. This also seems to happen on *.dwg files as well and not other files. This situation has been tested on word and excel files and it does not seem to happen with them.

Computers are on XP pro, Server environment XP and the software is ADT 2006 w/ SP1 installed (please don't move to ADT forums - I believe this is an AutoCAD issue at heart and should be here in the AutoCAD forum unless you feel another one is more appropriate). Please let me know if you can shed any light on this confounding situation as I haven't a clue why this would happen!

[Brian Myers]

The file is on the server. Computer B always takes over the file. Can I assume computer A and B are always the same computers?

Does computer A create a DWK or DWL file? I'm thinking that perhaps Computer A doesn't create a successful drawing lock which allows computer B to open the file. When computer A tries to save it it reads the drawing lock created by computer B and provides the error you see.

http://usa.autodesk.com/adsk/servlet...&linkID=518981

I'd log a support request if you have not already, it sounds like a permissions issue to me. It can easily be tested by seeing if a drawing lock is created by the first computer then the second since AutoCAD can't disable its drawing locking...

Edit: upon further thought in 2006 the drawing lock is controlled by the network software, not files (except DWG ownership) so this is basically out...

[Steve_Bennett]

The file is on the server. Computer B always takes over the file. Can I assume computer A and B are always the same computers?

Does computer A create a DWK or DWL file? I'm thinking that perhaps Computer A doesn't create a successful drawing lock which allows computer B to open the file. When computer A tries to save it it reads the drawing lock created by computer B and provides the error you see.

http://usa.autodesk.com/adsk/servlet...&linkID=518981

I'd log a support request if you have not already, it sounds like a permissions issue to me. It can easily be tested by seeing if a drawing lock is created by the first computer then the second since AutoCAD can't disable its drawing locking...

This scenario has been tested on multiple stations, so A and B can be different. That's an interesting link. It's similar to this one which has a rather shocking statement: http://usa.autodesk.com/adsk/servlet...linkID=2475323

Unlike many other software programs, the Save function in AutoCAD involves releasing locks from files and either deleting or renaming them. The read-only error can occur if a request to rename or delete the original file arrives before the file lock is removed.

This would seem to go against all logic, but appearantly it would seem that if one opens a file while another is saving it at the same time that since the dwl is removed the file can be open before it is saved. Am I understanding this correctly?

[Brian Myers]

This would seem to go against all logic, but appearantly it would seem that if one opens a file while another is saving it at the same time that since the dwl is removed the file can be open before it is saved. Am I understanding this correctly?

No, actually I believe this is what its stating:

The computer says "Unlock the file" . The server is slow. AutoCAD then says "Save the file". The server still has not unlocked the file, its going much slower than AutoCAD. AutoCAD comes back with an error because the original lock is still in place.

[Brian Myers]

It is possible the server is slow enough that after the lock is removed the next version of AutoCAD may save first... which would create its own lock.

But the slowness of this server would almost be un-imaginable for it to be happening on a regular basis...

Are all these computers on the same hub? Was curious if perhaps since (or if) there is a steady data transfer if perhaps some packet loss was occurring... then again if it was there would be other more prominent issues besides this so that rules that out....

[Steve_Bennett]

It is possible the server is slow enough that after the lock is removed the next version of AutoCAD may save first... which would create its own lock.

But the slowness of this server would almost be un-imaginable for it to be happening on a regular basis...

Are all these computers on the same hub? Was curious if perhaps since (or if) there is a steady data transfer if perhaps some packet loss was occurring... then again if it was there would be other more prominent issues besides this so that rules that out....

I have no idea if they are all on the same hub or what their connection to the server is... I will talk with their IT folks again tomorrow and see. Thanks for thinking about it! Maybe others will have another idea after seeing this.

[Brian Myers]

I have no idea if they are all on the same hub or what their connection to the server is... I will talk with their IT folks again tomorrow and see. Thanks for thinking about it! Maybe others will have another idea after seeing this.

I had a bad hub about 5 years ago really mess-up my network, that can cause slower speeds not on the server, but TO the server, but it likely would be noticed in other ways such as drawing access times, etc. as well. But I doubt this is the issue in this case.... it still sounds like how the network was set-up. Wish I could have had a better answer!

[Steve_Bennett]

So no one else has any thoughts, huh? Buggers cause they say it's getting worse.

[Brian Myers]

So no one else has any thoughts, huh? Buggers cause they say it's getting worse.

Worse? How so?

[Steve_Bennett]

Worse? How so?

They say more people are starting to get the same error more frequently. I told them to not open drawings as read-only then. Of course we all know how well that! went over...