This is just my opinion. Others may, and likely will, disagree. But just
today, I came up with a reason to "log" to a UNIX file instead of a SYSOUT
or z/OS sequential data set, and especially the latter.

There are many pluses of SYSOUT or UNIX over a sequential data set. First,
you don't need to specify a SPACE= parameter. Second, unless you use an
existing sequential data set and use DISP=SHR, you can't see the output as
it is being generated. With SYSOUT, you can view it via SDSF. With a UNIX
file, you can use ISPF browse or perhaps even the "tail" command on a UNIX
shell session. The "tail" is nice because you can get to the bottom rather
quickly.

One major plus of a UNIX file over SYSOUT is if you have multiple "log" DDs
in the same step and you'd like the output to be interspersed. This
occurred to me because CA-Endevor enables multiple different traces by
using multiple different DD names. Suppose you'd like a consolidated log in
which each line was in close proximity to the other trace lines generated
around the same time. I cannot think of a way to do this with either SYSOUT
or a sequential data set. Perhaps I'm missing something.

But for the above, in UNIX, you can easily do:

// SET LOGFILE='/tmp/&SYSUID..this.trace'
//* OTHER JCL
//* TRACE DDS
//EN$TRALC DD PATH='&LOGFILE',
// PATHOPTS=(OWRONLY,OAPPEND,OCREAT),
// PATHDISP=(KEEP,KEEP)
// RECFM=FA,LRECL=133,BLKSIZE=133
//*
//EN$TRITE DD PATH='&LOGFILE',
// PATHOPTS=(OWRONLY,OAPPEND,OCREAT),
// PATHDISP=(KEEP,KEEP)
// RECFM=FA,LRECL=133,BLKSIZE=133
//*
//* AND SO ON.
//*

Because I specified "unblocked" output, each line is written to the file
immediately (OK, put in
the UNIX kernel's buffer for the file). The OAPPEND on each means that
every write operation is
prefixed with a "go to the end of the file" type operation. Since the
buffering for a given specific UNIX file is kept in a single file buffer in
the kernel, this means that the lines should be written to the in pretty
much time sequenced order.

Hope this is at least of some interest.

-- 
This is a test of the Emergency Broadcast System. If this had been an
actual emergency, do you really think we'd stick around to tell you?

Maranatha! <><
John McKown

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