The file issue is the minor issue. Its fairly straight forward and in a
few hours you will have it sorted out in your mind.
That is not where you will get your frustrations. The frustrations will
come from the hardware restraints that programmers had to works with 30
years ago. Their work-arounds and shortcuts worked, but you will regret
having to deal with them. The MOVE opcode can do things those
programmers needed done, but it will make you gasp, defining a numeric
field with varying lengths so it will fit on a printed page will mystify
you, defining a field as alpha or numeric, depending how you wish to use
it in your program will make you cringe. Seeing whole programs written,
and temporary files created, sorted, used, and destroyed just to do some
small piece of a report will trouble you. And, we haven't even begun to
discuss the hoops created by CL program manipulation of files.
In short, I have done dozens of these and they always start out looking
like _this_ one will be different. They never are, Programmers back
then did the best they could with what was available, but since then a
whole lot more has become available. I will offer this hint: if you are
going to do it, start with the smallest, least significant application
first. Get your feet wet, and get a success early on, so you will have
a better basis to decide whether or not to continue. My estimate is
that, once you understand what is happening in an application, you can
probably write the same thing, new, in 20% of the time it will take to
update the existing application.
But yes, the files can be keyed. The keys are contiguous and added to
the end of the record, even if they are identical to data fields in the
original record, There is also another feature called the ADDROUT file
which is a separate file made up of only addresses. A data file can
have any number of these detached address files, allowing an early
version of indexed files.
On 11/5/2013 11:08 AM, James H. H. Lampert wrote:
A couple of questions about S/36 files, prompted by a potential new
customer whose whole native system is apparently set up around them:
First, while I've occasionally futzed around with totally flat,
non-keyed files, and while I've used program-described mode to
circumvent level-check problems on externally-described files that
change regularly, but in a manner that's under our control, I don't have
a lot of experience with actual S-36 files. Am I correct in my
understanding that an S-36 file can be both flat and keyed at the same
time? Is there a convenient way to create a file indistinguishable from
an S-36 file on a V4 or V6 box that doesn't have any S-36 emulation
installed?
Second, can SQL access an S-36 file? Is it difficult?
--
JHHL
midrange.com
