> -----Original Message----- > From: Linux on 390 Port [mailto:[EMAIL PROTECTED] On > Behalf Of Alan Ackerman > Sent: Monday, May 19, 2008 12:09 PM > To: LINUX-390@VM.MARIST.EDU > Subject: z/Linux access to z/OS DASD > > One of my managers told me that since you could make both ECKD (FICON) > and SCSI (FCP) connections to the same IBM Storage subsystem, z/Linux > should be able to read z/OS data off the z/OS volumes, without any > special formatting by z/OS. I asked IBM and they said it couldn't be > done - z/Linux cannot read z/OS data and vice-versa. > > Is this correct?
No. z/OS cannot read Linux DASD if the DASD is "Open Systems" connected. However, if it is ECKD, then z/OS could theoritically read it. However, you'd need to implement the filesystem driver code on z/OS. This could be "user space" code that actually does EXCP processing (or XDAP) or one of the more advanced I/O methods. Come to think of it, BDAM might even work. But remember that if the filesystem is read-write to some Linux system at the time, the DASD may be "fuzzy" and not contain the actual data as would be seen by a Linux program. This is due to the aggressive caching done by Linux. Forget any read-write sharing. There be dragons there. And blown filesystems, too. There is a driver that runs on Linux which can read z/OS legacy datasets, but not z/OS UNIX files. Interpreting the data is your problem, not the I/O driver's! But I don't remember much about it. I think that it is READ-ONLY. Personal opinion time, doning Security Admin hat: There is NO way that I would allow a Linux system to directly access my z/OS datasets. Why? No ability to audit. No ability to restrict access and prove that access was restricted to authorized users (thinking of HIPAA data). Now, I __might__ consider it if only a very few z/OS volumes were even accessable from the Linux system and I could assure myself that the datasets on those volumes never contained any confidential information that might require auditing. > > If so, what would it take to make z/Linux able to read z/OS data > directly? New drivers? A new file system? How hard would this be to > write? > > I am aware that you can access z/OS data from z/Linux (or any Linux) > over the network via one of: > > * NFS mount > * Samba mount > * Co:Z Co-Processing Toolkit > > That's not what I am looking for here. Our objective is to lower z/OS > MIPS by moving workload to z/Linux. A network "mount" would certainly > cost some z/OS MIPS. Moving workload to z/Linux without moving data > would save money because IFLs cost less than standard engines and the > software cost of Linux is lower than that of z/OS. > > Alan Ackerman -- John McKown Senior Systems Programmer HealthMarkets Keeping the Promise of Affordable Coverage Administrative Services Group Information Technology The information contained in this e-mail message may be privileged and/or confidential. It is for intended addressee(s) only. If you are not the intended recipient, you are hereby notified that any disclosure, reproduction, distribution or other use of this communication is strictly prohibited and could, in certain circumstances, be a criminal offense. If you have received this e-mail in error, please notify the sender by reply and delete this message without copying or disclosing it. ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
