Date sent: Sat, 4 Sep 1999 19:31:55 -0400 (EDT) From: William Levak <email@example.com> To: firstname.lastname@example.org Subject: Re: CBM 8280 Send reply to: email@example.com > On Sat, 4 Sep 1999, Radioactive Warrior wrote: > > > How strong a feild do those home bulk-erasers generate? I don't own one > > but I have seen my friend use his to blank audio tape. How long does it > > take for the field orient all the media particles (10 sec? 100 sec?) > > Does it help at all to rotate the disk around the field many times to > > 'exercise' the particles or dosen't it matter? > > Bulk erasers come in many sizes and configurations. Whether you must > rotate the disk depends on the geometry of the magnetic field. Ones that I've only seen one. At Radio Shack. Quite expensive where I live. There are others? > use electomagnets are more efficient than ones using permanent magnets. > The electromagnet changes the magnetic field 120 (or 100) times per > second. It is this changing field that counteracts the residual field. I > use an eraser designed for video tapes. This is powerful enough to easily > penetrate floppy disks and audio tapes with little effort. The usual > procedure is to move the disk or the bulk eraser in a circular motion and > gradually pull the eraser away from the disk. Doing this 2 or 3 times is > generally enough to restore a disk to "new" condition. Military security > specifications prescribe the field strength and the number of times to > bulk erase in order to get a complete erase for each type of media. If > these specifications are followed, residual data cannot be recovered even > with the most sophisticated equipment. After all, that is the point of > the specifications. Say, sounds interesting. I wonder how they gather this residual data. Does that mean they'd have to have programs that can read half tracks and half sectors? If so, tell me more. - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail firstname.lastname@example.org.
Archive generated by hypermail 2.1.1.