Hi Dmitry,

>I didn't realize that backup programs will backup files while the program has files open.

Not necessarily every back up program. I meant professional backup systems on Windows XP/2003/Vista. On these operating systems back up tools can use system services such as Volumne Shadow Copy or their own routines to intercept file operations.

Acronis, for example, is a tool that backs up open files. NTBackup, which comes with Windows, supports VSS. BackupExec from Symantec would be another one.