Flock - Version 2.1 By using FLock, you can limit user access to those WindowsNT resources that are initially "defenceless" such as floppy disk drives, CD-ROM drives, parallel and serial ports of the computer. It is implemented as a driver, its protection acts just from the system loading. FLock takes only a few system resourses and doesn't load the processor, because it doesn't participate in input-output operations.