Any reason why you can't ftp directly between the two z/OS system?
If security is an issue you could use either IPSec tunnels between the
two systems or setup IBM SecureFTP server (SSL'ed FTP).
Bruce Baxter wrote:
We've routinely exhanged files with business partners running on z/OS
machines using tape for years.
We're now in the process of converting a number of these to electronic
means, using in part FTP. This is being done at the behest of one of our
business partners, who (IMHO) hasn't thought through all the issues that the
use of FTP introduces in this process. The central issue as I see it is that the
mainframes at either end of the pipeline are both EBCDIC and record oriented,
and the servers and ftp processes that lie between them to facilitate these
transfers do not have any inherent concept of record oriented files like the
mainframe.
I'm going to treat FIXED BLOCK data separately from VARIABLE BLOCKED data
separately.
The first files that we received were FIXED BLOCK, and had been translated
from EBCDIC to ASCII, most likely at the first transfer of the file from z/OS to
an ASCII based server platform (either Windows or AIX). When they arrived
on our z/OS system, we had issues of data corruption because the data
contained zoned decimal data. After some discussion, we agreed that we'd
transfer these files in BINARY mode at all steps along the way. Thus, all we
had to do was ensure that the LRECL used for the destination dataset on
z/OS was the same as the source dataset. This seems to be working OK.
Most recently, we've been having problems with other files that are VARIABLE
BLOCKED. We received the first of these files last week, transmitted from end-
to-end in BINARY mode. What we got was not at all what we expected.
We've discovered that the initial FTP from z/OS to the server stripped off all
information regarding record length and thus record delineation. Because
there aren't any RDWs in front of every record, ftp doesn't know how long the
records are and just plunks the data into the destination dataset in chunks of
LRECL-4. I did a bunch of research on z/OS FTP and there doesn't appear to
be any way to make it convey record length/delineation information to and
ASCII platform other than to use ASCII mode. z/OS FTP appears to have
mechanisms for conveying this between two z/OS FTP systems, but that's not
possible here. For the present time, we've had the file shipped with the initiatl
movement translating the data from EBCDIC to ASCII and all subsequent
transfers until the last one back to z/OS in BINARY mode. However, I'm
concerned about the possibility of data corruption if the translate tables used
in the first step and the last step of this files travel aren't exact inversions of
each other. This would certainly be possible of the initial ASCII transfer were
done to a Windows Code Page 1252 system and the last transfer (having
CP1252 data) were translating between UTF-8 and CP037.
I'm interested in other folks war stories and what they've implemented for best
practices. I've made clear to our developers and end-users that ftp is
certainly not a direct replacement for tape transfers. It would appear that we
need lots of information about all the systems and transformations done in
moving the file from one system to another. FTP doesn't convey this sort of
information in any way shape or form.
What sort of options are there?
- Transmit/Receive would certainly be one, but would add a lot of overhead to
the process.
- Removal of all non-display data from the files and subjecting them to ASCII
translation at every step would also be an option, but that would likely be
rejected by our business partner as too much work.
- Are there any options to z/OS FTP that would allow record formatting
information to be conveyed in the file, if we presume that we'd transfer it in
binary mode at every step.
Has anyone come across any clear helpful best practice type information or
sites? I'd be interested in anything anyone has.
Regards,
Bruce Baxter
Manager of DP Tech Services
NYS Dept of Tax and Finance.
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