Microsoft's specs development procedures cause DISA advisers to say no to DCOM

Microsoft Corp. operating systems may be low-cost and easy to use, but they fall short
of Defense Department requirements for openness, said Terry Bollinger, principal
information systems engineer for Mitre Corp. of Bedford, Mass.


Bollinger, a technical adviser to the Defense Information Systems Agency, said
Microsoft’s closed procedures for developing technical specifications led him and
other DOD technical advisers to recommend against deploying battlefield applications that
rely on Microsoft’s Distributed Component Object Model definitions.


Their conclusion, presented in a recent DOD internal study [GCN, May 18, Page 38],
fueled considerable interest in binary-level software called middleware, said Bollinger, a
principal author of the study.


Microsoft’s DCOM and competing middleware specifications known as the Common
Object Request Broker Architecture and Distributed Computing Environment are current hot
topics within DISA, which sets information systems standards for the department.


CORBA is “quite a bit easier and cheaper to use” with Windows systems than
DCOM is to use with Unix systems, Bollinger said. But DCOM is a reasonable choice for
“the Windows-only regions of a distributed system,” he said.


Bollinger said the study’s endorsement of CORBA applies in circumstances that
require near-real-time communications between geographically distributed parts of a single
application program.


Most significant to DOD is how Microsoft and CORBA’s sponsor, the Object
Management Group of Framingham, Mass., develop their respective standards.


OMG develops and maintains the CORBA specification and interface definition language
through an open, public process, Bollinger said. Microsoft’s DCOM process, however,
is closed, he said.


Bollinger said each way has advantages and disadvantages. But full disclosure of
technical definitions and modifications is a mission-critical requirement for stable and
proper functioning of battlefield applications, he said.


CORBA’s openness is inherently more compatible with software stability and legacy
system interfaces, Bollinger said.


CORBA’s technical definitions and its interface definition language are easy to
obtain over the Internet and evaluate to any desired level of detail, Bollinger said.


Because Microsoft’s development procedures for DCOM are private, “the quality
and stability of its internal interfaces cannot be readily ascertained and could change
abruptly,” Bollinger said.


Defense officials are concerned about the destabilizing effect that internal interface
modifications could have on already-fielded systems if Microsoft made such changes
unilaterally, Bollinger said.


But the CORBA vs. DCOM debate could wind up a moot issue, Bollinger said, if Microsoft
were to make greater use of new technologies such as the Extended Markup Language to carry
out the structured data transfers that object-oriented middleware now handles.


Unlike DCOM, XML is an open and publicly defined technical definition. Moreover,
Microsoft has been active in developing XML standards, Bollinger said.


For processing large text files, he said, the combination of XML with languages such as
Perl might be easier and better than either DCOM or CORBA.


For real-time processing, Bollinger said, the binary message format becomes a minor
consideration in choosing middleware. More important, he said, is having middleware that
can keep applications working across large global networks despite many faulty links and
nodes.


Microsoft’s Transaction Server is clearly heading in that direction, Bollinger
said.


The DISA study is downloadable from the Web at http://sw-eng.falls-church.va.us/coe/topics/atd/.
 

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