Apple did it with OS X. Then it was Intel with Itanium 2. Now it is Microsoft with Windows Server 2003. Maintaining backward compatibility, and with it the tons of legacy baggage, does not seem to be popular anymore.
And those planning to upgrade to Windows Server 2003 will have to be prepared for the fact that many older versions of Microsoft's most popular server applications will not run on the new server operating system if they have not done their homework.
For example, users running SQL Server 6.5 or 7.0 will have to upgrade their SQL server or wait for the new SQL release, code-named Yukon, which will go into beta testing soon.
Only SQL Server 2000 with Service Pack 3 can be installed onto Windows Server 2003.
Exchange Server users have even less of a choice with the only version that can be installed onto the Windows Server 2003 being Exchange 2003, and that won't be available until later this quarter.
According to Microsoft central marketing organisation product manager, Danny Ong, there are four main reasons for the changes that affect application compatibility.
These are: the removal of legacy components, tightening of security, changing to a more conservative default setting as well as removing applications that depend on specific version of Windows which is particularly important for applications that feature kernel-mode components or drivers.
While Microsoft is not a name commonly associated with the idea of legacy systems, Microsoft does have one of the largest installed bases of legacy systems by its sheer dominance of the desktop platform.
Hence, maintaining backward compatibility to ensure enterprises' significant investments in their existing applications remains a key consideration.
"We are extremely mindful that customers expect to have backward compatibility when they upgrade," Ong said.
However, he said that security, another key issue brought up by customers, was more important than compatibility.
Many users were sympathetic to Microsoft's stand that extensive security improvements affected not only the operating system but the applications relying on it as well.
However, some local IT managers are still concerned.
"A lot of CD-ROMS brought to Library may not be used, and the administration software may be affected by the issue of compatibility," said Chia Keng Hian, who heads the Information Technology department at Hwa Chong Junior College. According to Chia, compatibility will certainly be an issue when it comes to the school's upgrade decisions.
Microsoft has put together some resources for customers to ease the pain of transition. It has put up a white paper explaining the different categories of common application compatibility issues as well as a toolkit, Windows Application Compatibility Toolkit, that contain tools and documentation needed to design, deploy and support applications on Windows .Net.
The toolkit includes an Application Compatibility Analyzer that collects application information from a computer. This can be used to create an inventory of the applications used in the enterprise.
It also includes a Compatibility Advisor that allows an administrator to determine the correct combination of compatibility fixes required to properly support the application and apply the fixes through a single compatibility database.