It is part of the Windows NT family of operating systems and was released to manufacturing on March 28, 2003[14] and generally available on April 24, 2003.

Its successor, Windows Server 2008, requires a processor with ACPI in any supported architecture (x86, x64 and Itanium).

Windows Server 2003 includes compatibility modes to allow older applications to run with greater stability.

After Microsoft chose to focus the ".NET" branding on the .NET Framework, the OS was finally released as "Windows Server 2003".

[18] Pre-reset builds of "Longhorn" were based on the Windows .NET Server Release Candidate 1 (3663) codebase, whereas post-reset builds of "Longhorn/Vista" after the development reset in 2004 are based on the works-in-progress Windows Server 2003 Service Pack 1 (3790.1232) codebase.

[23] Windows Server 2003 was the first Microsoft Windows version which was thoroughly subjected to semi-automated testing for bugs with a software system called PREfast[24] developed by computer scientist Amitabh Srivastava at Microsoft Research.

[27] There was also a notable change in the ability to create a rescue disk, which was removed in favor of Automated System Recovery (ASR).

[32] Other notable new features include support for a hardware-based "watchdog timer", which can restart the server if the operating system does not respond within a certain amount of time.

[42][clarification needed] Microsoft Windows Server 2003 Standard is aimed towards small to medium-sized businesses.

Standard Edition supports file and printer sharing, offers secure Internet connectivity, and allows centralized desktop application deployment.

It is a full-function server operating system that supports up to 8 physical processors and provides enterprise-class features such as eight-node clustering using Microsoft Cluster Server (MSCS) software and support for up to 64 GB of RAM through PAE.

Windows Server 2003 Enterprise is also the required edition to issue custom certificate templates.

[citation needed] Windows Server 2003 Datacenter is designed[44] for infrastructures demanding high security and reliability.

[41] Windows Server 2003 Datacenter also allows limiting processor and memory usage on a per-application basis.

MS MPI was designed to be compatible with the reference open source MPI2 specification which is widely used in High-performance computing (HPC).

[50] Windows Storage Server 2003 NAS equipment can be headless, which means that they are without any monitors, keyboards or mice, and are administered remotely.

[51] Such devices are plugged into any existing IP network and the storage capacity is available to all users.

Windows Storage Server 2003 can use RAID arrays to provide data redundancy, fault-tolerance and high performance.

This release adds file-server performance optimization, Single Instance Storage (SIS), and index-based search.

Windows Storage Server 2003 R2 includes built in support for Windows SharePoint Services and Microsoft SharePoint Portal Server, and adds a Storage Management snap-in for the Microsoft Management Console.

Windows Storage Server 2003 R2 can be used as an iSCSI target with standard and enterprise editions of Windows Storage Server 2003 R2, incorporating WinTarget iSCSI technology which Microsoft acquired in 2006 by from StringBean software.

Windows Storage Server 2003 can be promoted to function as a domain controller; however, this edition is not licensed to run directory services.

[60] Windows Small Business Server (SBS) is a software suite which includes Windows Server and additional technologies aimed at providing a small business with a complete technology solution.

[64] Windows Home Server was announced on January 7, 2007, at the Consumer Electronics Show by Bill Gates and is intended to be a solution for homes with multiple connected PCs to offer file sharing, automated backups, and remote access.

All variants continued to receive Critical security updates until the end of extended support:[70] Release 2 for Embedded Systems was available in 32 and 64 bit variants, Standard (1-4 CPU) and Enterprise (1-8 CPU):[71] Windows XP Professional x64 Edition was released less than a month after Windows Server 2003 SP1,[72] and used the same kernel and source code tree.

[citation needed] On March 30, 2005, Microsoft released Service Pack 1 for Windows Server 2003.

Features that are added with Service Pack 1 include: A full list of updates is available in the Microsoft Knowledge Base.

SNP was previously available as an out-of-band update for Windows Server 2003 Service Pack 1.

Anonymous users managed to compile the Windows Server 2003 source code, as well as a Twitter user who posted videos of the process on YouTube proving that the code was genuine,[91] but was removed from the platform on copyright grounds by Microsoft.

[92][93] The original leak itself was spread using magnet links and torrent files whose payload originally included Server 2003 and XP source code and which was later updated by additional files among which were previous leaks of Microsoft products, its patents, media about conspiracy theories about Bill Gates by anti-vaccination movements and an assortment of PDF files on different topics.