From 2df950ee5f5f41b4ec601957c4085a8cd006e1bf Mon Sep 17 00:00:00 2001 From: schmidt Date: Thu, 26 Jun 1997 04:13:21 +0000 Subject: *** empty log message *** --- docs/ACE-lessons.html | 267 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 267 insertions(+) create mode 100644 docs/ACE-lessons.html (limited to 'docs') diff --git a/docs/ACE-lessons.html b/docs/ACE-lessons.html new file mode 100644 index 00000000000..64c8db551ef --- /dev/null +++ b/docs/ACE-lessons.html @@ -0,0 +1,267 @@ + + + +Lessons Learned Building Reusable OO Telecommunication Software + + + + +
+

Lessons Learned Building Reusable OO Telecommunication Software Frameworks

+ +
Douglas C. Schmidt +
Department of Computer Science +
Washington University, St. Louis +
http://www.cs.wustl.edu/~schmidt/ +
schmidt@cs.wustl.edu + +

The following article appeared in the Lucent Bell Labs ``Multiuse +Express'' magazine, Vol. 4, No. 6, December, 1996.

+ +

+ +

The Distributed Software Crisis

+ +Developing complex software systems is expensive and error-prone. +Object-oriented (OO) programming languages [Stroustrup:91,Gosling:96], +components [Box:97], and frameworks [Lewis:95] are heavily touted +technologies for reducing software cost and improving software +quality. When stripped of their hype, the primary benefits of OO stem +from the emphasis on modularity and extensibility, +which encapsulate volatile implementation details behind stable +interfaces and enhance software reuse.

+ +Developers in certain well-traveled domains have successfully applied +OO techniques and tools for years. For instance, the Microsoft MFC +GUI framework and OCX components are de facto industry +standards for creating graphical business applications on PC +platforms. Although these tools have their limitations, they +demonstrate the productivity benefits of reusing common frameworks and +components.

+ +Software developers in more complex domains like telecom have +traditionally lacked standard off-the-shelf middleware components. As +a result, telecom developers largely build, validate, and maintain +software systems from scratch. In an era of deregulation and stiff +global competition, this in-house development process is becoming +prohibitively costly and time consuming. Across the industry, this +situation has produced a ``distributed software crisis,'' where +computing hardware and networks get smaller, faster, and cheaper; yet +telecom software gets larger, slower, and more expensive to develop +and maintain.

+ +The challenges of building distributed software stem from +inherent and accidental complexities [Brooks:87] +associated with telecom systems:

+ +

+ +The lack of extensibility and reuse in-the-large is particularly +problematic for complex distributed telecom software. Extensibility +is essential to ensure timely modification and enhancement of services +and features. Reuse is essential to leverage the domain knowledge of +expert developers to avoid re-developing and re-validating common +solutions to recurring requirements and software challenges.

+ +While developing high quality reusable software is hard enough, +developing high quality extensible and reusable telecom software is +even harder. Not surprisingly, many companies attempting to build +reusable middleware fail -- often with enormous loss of money, time, +and marketshare. Those companies that do succeed, however, reap the +benefits resulting from their ability to develop and deploy complex +applications rapidly, rather than wrestling endlessly with +infrastructure problems. Unfortunately, the skills required to +successfully produce telecom middleware remain something of a "black +art," often locked in the heads of expert developers.

+ +

+ +

Lessons Learned Building Reusable OO Communication Software Frameworks

+ +Over the past decade, I've worked with many companies (including +Motorola Iridium, Ericsson, Siemens, Bellcore, Kodak, and McDonnell +Douglas) building reusable OO communication software [Schmidt:96]. In +these projects, we've applied a range of OO middleware tools including +OMG CORBA (an emerging industry standard for +distributed object computing) and the ACE +framework (a widely used C++ framework that implements many strategic +and tactical design patterns for concurrent communication software). +The following are lessons learned from developing and deploying +reusable OO communication software components and frameworks in +practice:

+ +