> -----Original Message----- > From: IBM Mainframe Discussion List > [mailto:[EMAIL PROTECTED] On Behalf Of Dave Thorn > Sent: Thursday, May 19, 2005 11:42 AM > To: [email protected] > Subject: "Leftover" data: can it be seen? > > > A customer (through an auditor) has posed a question to us: > Job 'A' runs > and ends. Job 'B' then comes in and obtains some of the > system storage > that Job 'A' had. The question is, can Job 'B' see data in > that memory > originally owned by Job 'A'? > > Theoretically, yes, right? Is there a way to prevent this? > (which I'm > sure will be the followup question) I know this sounds a > little silly but > it seems to be a concern to someone. > > Thanks in advance for any insights. > > > Dave Thorn > Senior Technology Analyst
No, it cannot. When Job "A" terminates, all the real storage frames and aux page slots are "freed". Before assigning a new (never been used by this process) real storage frame (4K unit of memory), z/OS will write binary zeros into it. As for aux slots, they are not brought into memory unless they were previously paged out by this particular process, so the previous contents are "lost". Granted, the contents are on aux until the slot is reused. But a "freed" aux slot is never paged in. This does mean that a program which can read the page datasets could get ahold of information which it should not. So, bottom line: There are no "leftovers" when an address space terminates. -- John McKown Senior Systems Programmer UICI Insurance Center Information Technology This message (including any attachments) contains confidential information intended for a specific individual and purpose, and its' content is protected by law. If you are not the intended recipient, you should delete this message and are hereby notified that any disclosure, copying, or distribution of this transmission, or taking any action based on it, is strictly prohibited. ---------------------------------------------------------------------- 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
