differential database backup

Hi,
How sql server keep track of what modified since last full
database backup while taking differential database backup?
I checked Backup/Restore Architecture in books online, no
luck.
Please reply.
Ram.the super short answer is that SQL Server has some interenal meta data that
allows it to track which extents have been changed since the last
differential. The next differential just reads that map and backs up those
extents...
the best source for info like this is Kalen Delaney's Inside MS SQL Server
2000....
--
Brian Moran
Principal Mentor
Solid Quality Learning
SQL Server MVP
http://www.solidqualitylearning.com
"Ram" <mail_info@.rediffmail.com> wrote in message
news:03ed01c3517e$e2f21170$a601280a@.phx.gbl...
> Hi,
> How sql server keep track of what modified since last full
> database backup while taking differential database backup?
> I checked Backup/Restore Architecture in books online, no
> luck.
> Please reply.
> Ram.