SQL Server differential backups in a Simple recovery model

Question

I created full backup on 1/1/2021. Then i stopped doing full backups. For a month I was doing just differential backups.

If I restore full backup with norecovery, would I be able to restore 2/2/2021 differential backup? I don't know how differential backup on 2/2/2021 would know about all the changes since 1/1/2021

question from:https://stackoverflow.com/questions/66059667/sql-server-differential-backups-in-a-simple-recovery-model

Answer 1

"If I restore full backup with norecovery, would I be able to restore 2/2/2021 differential backup?" --- YES

"how differential backup on 2/2/2021 would know about all the changes since 1/1/2021" --- through bitmap . "The differential backup operation relies on a bitmap page that contains a bit for every extent. For each extent updated since the base, the bit is set to 1 in the bitmap."