[AccessD] How does Access locking work

Drew Wutka DWUTKA at Marlow.com
Thu Sep 15 11:23:55 CDT 2011


Stored in memory, by the OS.

I know your programming days pre-date mine, so you should have had file
writes where you were writing a specific section of a file.  The OS
'locks' the section you are telling it you are writing to, then it
performs the write.  Same process with the .ldb lock, just a write never
occurs.  

Drew

-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com] On Behalf Of jwcolby
Sent: Thursday, September 15, 2011 6:35 AM
To: Access Developers discussion and problem solving
Subject: Re: [AccessD] How does Access locking work

So what is a lock?  Something written to disk I assume?  Where?
Completely stored in memory? How do I speed that up.

John W. Colby
www.ColbyConsulting.com

On 9/15/2011 1:51 AM, Drew Wutka wrote:
> I think I have the old Jet white paper somewhere.  But basically Jet 
> would 'lock' the .ldb file where it needed to lock the .mdb.  So the 
> .mdb would never be locked (allowing for multiple edits), and the lock

> on the .mdb would be actually on the .ldb file.
>
> So say the .mdb was 100 megs.  And it needed to lock the 50th 
> megabyte, the .ldb file was always small (I think it was 64 bits per 
> user, up to
> 255 users), so it would never reach the 50 meg size, but the 'lock'
> would be placed on the 'virtual' 50 meg point of the .ldb.
>
> Make sense?
>
> Drew
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