|Microsoft Windows 2000|
|Codename(s)||Memphis NT, NT 5.0|
|Kernel version||NT 5.0|
|CPU Architecture||x86, IA-64|
|Support end||Extended Support Period until 13 July 2010|
Neptune / XP
Windows 2000 (Codename Memphis NT, NT 5.0) was the last version of the Windows NT line of operating systems which was released for business users only. It also dropped the NT name, although it is still branded with "Based on NT Technology".
It was originally supposed to be called Windows NT 5.0, but after the drop of future successors Neptune, Odyssey, and Triton, Whistler was planned and it was soon renamed to Windows 2000.
- 1 Editions
- 2 Service Packs
- 3 Builds
Windows 2000 was released in Workstation (Professional) and Server (Advanced Server , Datacenter Server , Server) editions.
Informations about each edition borrowed from Wikipedia, the free encyclopedia
It is the client version of Windows 2000. It offers greater security and stability than many of the previous Windows desktop operating systems. It supports up to two processors, and can address up to 4 GB of RAM. The system requirements are a Pentium processor (or equivalent) of 133 MHz or greater, at least 32 MB of RAM, 650 MB of hard drive space, and a CD-ROM drive (recommended: Pentium II, 128 MB of RAM, 2 GB of hard drive space, and CD-ROM drive).
It shares the same user interface with Windows 2000 Professional, but contains additional components for the computer to perform server roles and run infrastructure and application software. A significant new component introduced in the server versions is Active Directory, which is an enterprise-wide directory service based on LDAP. Additionally, Microsoft integrated Kerberos network authentication, replacing the often-criticised NTLM authentication system used in previous versions. This also provided a purely transitive-trust relationship between Windows 2000 domains in a forest (a collection of one or more Windows 2000 domains that share a common schema, configuration, and global catalog, being linked with two-way transitive trusts). Furthermore, Windows 2000 introduced a Domain Name Server which allows dynamic registration of IP addresses. Windows 2000 Server supports up to 4 processors, requires 128 MB of RAM and 1 GB hard disk space, however requirements may be higher depending on installed components.
It is a variant of Windows 2000 Server operating system designed for medium-to-large businesses. It offers clustering infrastructure for high availability and scalability of applications and services, including main memory support of up to 8 gigabytes (GB) on Physical Address Extension (PAE) systems and the ability to do 8-way SMP. It supports TCP/IP load balancing and enhanced two-node server clusters based on the Microsoft Cluster Server (MSCS) in Windows NT Server 4.0 Enterprise Edition. Limited number of copies of an IA-64 version, called Windows 2000 Advanced Server, Limited Edition were made available via OEMs. System requirements are similar to those of Windows 2000 Server, however they may need to be higher to scale to larger infrastructure.
It is a variant of Windows 2000 Server designed for large businesses that move large quantities of confidential or sensitive data frequently via a central server. Like Advanced Server, it supports clustering, failover and load balancing. Its minimum system requirements are normal, but it was designed to be capable of handing advanced, fault-tolerant and scalable hardware—for instance computers with up to 32 CPUs and 64 GBs RAM, with rigorous system testing and qualification, hardware partitioning, coordinated maintenance and change control. Limited number of copies of an IA-64 version, called Windows 2000 Datacenter Server, Limited Edition were made available via OEMs. System requirements are similar to those of Windows 2000 Advanced Server, however they may need to be higher to scale to larger infrastructure.
There were four service packs released for Windows 2000.
Service Pack 1
Service Pack 1 has been released on 15 August 2000.
Service Pack 2
Service Pack 2 has been released on 16 May 2001.
Service Pack 3
Service Pack 3 has been released on 29 August 2002.
Service Pack 4
Service Pack 4 has been released on 26 June 2003.
Update Rollup 1
Update Rollup 1 for Service Pack 4 is a collection of hotfixes, mainly for the security-related issues. It is said to contain all the security-related hotfixes and some non-security updates released between SP4 and UR1 for SP4. This rollup has been released instead of Service Pack 5. 
Service Pack 5
Microsoft planned to release Service Pack 5, but it has been cancelled and Update Rollup for SP4 has been released instead. 
- Windows NT 5.0 Build 1515.1
- Windows NT 5.0 Build 1585.1
- Windows NT 5.0 Build 1592.1
- Windows NT 5.0 Build 1631.1
- Windows NT 5.0 Build 1796.1
- Windows NT 5.0 Build 1877.1
- Windows NT 5.0 Build 1902.1
- Windows NT 5.0 Build 1906.1