I think it varies the pattern for each cycle. IIRC (memories from the 'nam days) the number of cycles had to be at least 8 for any magnetic media that had anything classified written on it at any time. The CAD folks claimed to be able to recover information from several levels deep at that time, so 8 = several + some undisclosed constant. (Did the intelligence services of 1967 presage the vertical recording of today?) If there was nothing classified on the disks the rules were relaxed.
You need to use current rules to determine the number of cycles. Regards, Richard Schuh -----Original Message----- From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On Behalf Of Ed Zell Sent: Wednesday, January 31, 2007 1:14 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: ICKDSF Release 16 > We are in the process of 'decommissioning' our mainframe platform > (MP3000 runing v/VM 3.1). We formatted all our internal and > external DASD (3380s and 3390s) using ICKDSF R16 with the > following command: I found this in a recent post by searching the archives at: http://listserv.uark.edu/archives/ibmvm.html Look at ICKDSF TRKFMT FROMRANGE(0,0) ERASEDATA CYCLES(n). It writes a "special pattern" (as opposed to binary zeroes, I guess). Ed Zell (309) 674-8255 x-107 [EMAIL PROTECTED] . CONFIDENTIAL NOTICE: This communication, including any attachments, is intended only for the use of the individual or entity to which it is addressed and contains information which may be confidential. If you are not the intended recipient, any distribution or copying of this communication is strictly prohibited. If you have received this communication in error, notify the sender immediately, delete the communication and destroy all copies. Thank you for your compliance.