Bill Fairchild wrote:
In a message dated 7/27/2005 9:19:58 P.M. Central Daylight Time,
[EMAIL PROTECTED] writes:
I was wondering if ZAP would/not allow one to
retrieve data from a track that had been "cleared" by writing R0 or EOF at
beginning of the track. I guess Radoslaw Skorupka's English comes out better
than mine. Can I blame it on American television? Hmm, no, come to think of
it. English is NOT spoken on 'American' television'.
?Anykahow, will ZAP recover data as asked?
IMASPZAP will not retrieve or recover data, if I understand what I think you
mean by those words. ZAP will only read what is on the track and format it
for displaying to the SYSPRINT file, which is typically then read into a
human's eyeball subsystem. It can be used to change what is already there, but
it cannot be used to shorten or lengthen a DASD block. In the case of an EOF
block with data length 0, nothing can be done by ZAP to the data in that
block because the data field has been formatted as having a zero length and thus
there is no data field. If the data length were greater than 0, than the
contents of the data field could be changed, but the data length cannot be
changed, e.g., from 3120 to 256 by ZAP. Whatever data was on the track to begin
with is erased when a new R0 is written, or when an EOF block is written at
the beginning (which means right after R0, and which is almost always called
R1).
As I understood David's American language <g>, he meant security
exposure, not data recovery possibility. In other words, ZAP can be used
(or cannot be - that is the question)to disclose data, unformatted, in
sysprint, etc. So there is risk a of "quick erase".
Regarding to the original question: I don't know whether ZAP can be used
for that, but I believe, it is protected by RACF DASDVOL/GDASDVOL class
profiles. At least VTOC is.
--
Radoslaw Skorupka
Lodz, Poland
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