In a message dated 6/30/2005 9:52:17 P.M. Central Daylight Time, [EMAIL PROTECTED] writes:
I went back to check the source code for the program I have for doing this level of 'CLEARING' a DASD. It does indeed write a record to allow the DASD to be used by subsequent users. Very good. The way the CKD controllers work is that whenever you have written the last piece of data onto a track using a formatting write command, the rest of the track after that point is erased. So if all you format write is the home address, then R0 and all the rest of the track is erased. If you format write the home address and R0 or only R0, then everything after R0 is erased. Etc. Later when you want to copy data onto the track from a backup tape, e.g., you have to access R0 before you can do a format write into R1, so if there is no R0 then you can never write R1, meaning you can't restore the track. Bill Fairchild ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
