Are tables locked during backup or can applications continue to write to tables?

I hope to use SQLBackupAndFTP on a PC controlling an industrial process. I am concerned that backup will lock the DB/tables for periods of time - short or long? - and that the machine application will try to write to the DB, timeout and error or crash.

Can you comment on this? Does SQLBackupAndFTP lock the tables during backup? If not, how are changes during backup handled?


Since SQLBackupAndFTP just runs BACKUP DATABASE command, take it from MSDN (

Performing a backup operation has minimal effect on transactions that are running; therefore, backup operations can be run during regular operations. During a backup operation, SQL Server copies the data directly from the database files to the backup devices. The data is not changed, and transactions that are running during the backup are never delayed. Therefore, you can perform a SQL Server backup with minimal effect on production workloads.