Microsoft Tuesday again delayed the release date for the first service pack for Windows Server 2003, a slip that also will hold up the release of Windows Server 2003 for 64-bit Extended Systems.

Windows Server 2003 SP1, which was scheduled to ship at the end of the year, will now be made available in the first half of 2005, according to Microsoft officials. This is the second delay for the service pack, which was originally set for release in 2003.

The fact that SP1 is the foundation for the 64-bit Extended Systems software, which is designed for the AMD Opteron and Intel Xeon EM64T processors, means that operating system software also was pushed back into 2005.

“As is the case with all Microsoft product schedules, the development cycle is driven by quality with a focus on the needs of our customers, rather than an arbitrary date,” said a Microsoft spokesperson in an e-mail message announcing the delay.

Microsoft has had difficulty hitting its target ship dates lately, most notably with multiple delays in the release of Windows XP SP2, now slated for next month, and patching tools Windows Update Services and Microsoft Update, which won’t ship until next year.

While the company routinely says customers have the final say on shipping software, Microsoft’s software development has been slowed in recent years by a push to educate developers in writing secure code and the fight against random and frequent security flaws in its software.

The first service pack for Windows Server 2003 is a companion to Windows XP Service Pack 2 and adds a slew of security tweaks, including turning on a personal firewall by default.

Windows Server 2003 SP1 incorporates some of the same security features as XP’s Internet Connection Firewall, including the lockdown of Remote Procedure Call and Distributed Component Object Model.

Just like with those features in XP, which have been shown to break some applications on their way to providing tighter security, users will have to thoroughly test the server software for the same pitfalls, according to experts.

Among its features, SP1 includes a Security Configuration Wizard, which aids in securely configuring servers for specific roles such as database or e-mail, and a boot-time network protection for clean installs. The service pack also has built-in VPN quarantine technology, the first step toward the Network Access Protection client isolation technologies that will ship with Windows Server R2, the next major upgrade of the server that also is planned for a 2005 release.