Bob wrote:
I did notice that they talked alot about z/OS in the posts about these
functions. I did say it was unix, though, in my original post. More
specifically, it is AIX. This place is all about the IBM.
DSN3xxx sounds very much like z/OS and not at all like DB2 LUW. Maybe you
are mixing some things here?
I don't get this about DB2 - what is with the functionalities on one
platform and not another? Why haven't they just wrapped the core
functionality with platform specific wrappers?
Because it is not that simple. Both DB2 products (actually 4 if you
consider DB2 Everyplace, DB2 for iSeries, DB2 z/OS, and DB2 LUW) take
advantage of the different features and restrictions on the respective
platform. For example, doing I/O operations on z/OS is completely
different than I/O on Unix. And because performance is the most critical
factor for any serious DBMS, it is not an option to introduce emulation
layers. Also, DB2 z/OS was initially (and still is) written PL/X and
Assembler. It also employs WLM for stored procedure/UDF execution - while
LUW always had a different process model for external routines simply
because WLM wasn't available in the beginning. This is not easily portable
to other platforms. DB2 for iSeries is integrated into the operating
system. This is yet another model, and DB2 Everyplace (still) has to work
on very limited hardware and you can't even install a full-blown Enterprise
Server Edition.
So you see that there are many good reasons why different architectures are
used. I guess that everyone why worked with the some of those different
platforms can understand those differences. What IBM tries to do is to
present a mostly consistent user/application interface while still taking
advantage of platform-specific features. But again, you have to consider a
different customer set on LUW and z/OS, for example. If certain features
are more important on LUW, they have a higher chance to get into the
development plans on LUW than on z/OS and maybe not at all in DB2
Everyplace.
--
Knut Stolze
DB2 z/OS Utilities Development
IBM Germany