Puzzling Address Book problem

[packman 0]

Relevant: Internet Explorer6 SP1/Outlook Express 6 SP1, Windows 2K SP4, Nero 5.5.

 

I've just encountered a strange occurrence in the functioning of the Address Book in Outlook Express and am wondering if anyone can throw some light on it.

 

As a precaution for backing up, I've exported the contents of my Address Book to several places: to a DVD-RW, to a DVD+R, and to a folder in a separate partition on the hard disk. To write the file to the DVDs, I first exported the Address Book to the partition. I then copied the file to the DVD-RW using drag n' drop but, of course, had to use Nero to copy it to the DVD+R.

 

Naturally, I've wanted to read the contents of these written copies, to check that they have indeed written properly. However, I find that I can open the versions that I put on the partition and on the DVD-RW (ie. the addresses.WAB files will open in Address Book by just clicking on the file) but I can't open the file that was put on the DVD+R. Instead, I get a Windows error message, saying "The Address Book has been locked by another application. Please close the other application and try again later".

 

Well, there is no other application open, so what's going on here? I've tried changing the read-only attributes of the file on the DVD+R but that has no effect on the problem.

 

There's nothing wrong with the DVD+R disc itself, as I've successfully written plenty of other files on to it.

 

I could, of course, go to the Address Book and try importing the file from there, but I don't want to risk importing nothing.

 

Is there something about write-once media that makes it completely unsuitable for storing the contents of the Address Book?

[Wilhelmus 1]

Quote:

http://www.netguide.com.au/useful_stuff/helpdesk/showitem.php?id=914

You can’t. When opening the WAB address books, the file is left open for writing. A CD that is ‘read only’ will not allow you to do so. What you will have to do is copy the WAB file into your hard drive (say, the desktop) when you want to use it.

[packman 0]

Actually, I've already tried that, Wilhemus, (ie. dragging on to the Desktop and executing from there) and that too refused to work, giving the error message again "The Address Book has been locked......try again later".

 

[Wilhelmus 1]

Originally posted by packman:

Quote:

I've tried changing the read-only attributes of the file on the DVD+R

Have you tried to remove the read-only attribute from the file which you have copied to desktop?

 

[packman 0]

I just tried that and you're right, it does work. But why should removing the Read-Only attribute make it openable (readable)? It doesn't seem to follow any particular logic.

[Sampson 0]

Essentially, Outlook express uses a database storage system. There are Windows operating locks on files which are nothing other than the attributes like archive, read only, system, and hide to name a few. But, when a database wants to open a read only file, the database "perceives" the record as locked and therefore as being used by someone else and will not release that record to you until someone finishes changing the columns in that record, It is called record locking and is standard operating procedure in all databases. If two users were to access the same record at the same time, the database would not know which users had the most correct information, so it automatically locks all others out until the first one who accessed the record is finished. Hence, a read only file (which may have multiple records) is "perceived" by the database attempting to access those records as all locked and therefore it can access none of them.

[packman 0]

Yes, but in this case the Address Book was not in the middle of being changed by me or anyone else, so why should it be perceived at all as being 'locked out'? It simply doesn't explain why it is that, with the addresses.wab file stored in a write-read medium, you can open the Address Book from the file, but with it stored in a write-only medium, you can't (unless you drag the file to the Desktop first).

 

 

[Sampson 0]

You know that the file isn't being changed, but the database doesn't. The database interprets the read only status at the file level to be a lockout of all the records within the file. It therefore cannot open any of the records in any part of the file. That's just the way databases work to avoid "the dreaded record lock problem." Just as Asimov invented the three-fold rule to keep robots from killing humans (though there was a loophole), designers of databases created as their first rule that no two users could work on the same record at the same time to preserve data integrity (later, the better databases limited it to "no two users could access the same field in the same record at the same time.")