The Diskette Workshop
By formatting sectors of unusual size and ID, they are hidden for the general user. Such areas can coexist with the standard sectors without showing at all. Whoever you are, it is obvious that such sectors do not create themselves. Therefore they have been created with intention.
Some are on whole batches of pre-formatted diskettes. Some have diskette manufacturers numbers. Even if this is the case, they are there and ready for storage of any data. Some have Industrial SPY's collected information. Some carry virus, worms and catalyzer data. The BOOT sector is not used!No Virus Scanner tests for SPY sectors.
The Diskette Workshop does.