Windows 2000

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Windows 2000
(Part of the Microsoft Windows family)
Screenshot
Screenshot of Windows 2000 Professional
Developer
Microsoft
Web site: www.microsoft.com/windows2000
Release information
Release date:	February 17, 2000 info
Current version:	5.0 SP4 Rollup 1 ( September 13, 2005) info
Source model:	Closed source
License:	Microsoft EULA
Kernel type:	Hybrid kernel
Support status
Extended Support Period, only security updates will be provided unpaid.

Windows 2000 (also referred to as Win2K) is a preemptible, interruptible, graphical and business-oriented operating system that is designed to work with either uniprocessor or symmetric multi-processor 32-bit Intel x86 computers. It is part of the Microsoft Windows NT line of operating systems and was released on February 17, 2000. It was succeeded by Windows XP in October 2001 and Windows Server 2003 in April 2003.

Windows 2000 is classified as a hybrid kernel operating system, and its architecture is divided into two modes: user mode and kernel mode. The kernel mode provides unrestricted access to system resources and facilitates the user mode, which is heavily restricted and designed for most applications.

Windows 2000 was made available in four editions: Professional, Server, Advanced Server, and Datacenter Server. Additionally, Microsoft offered Windows 2000 Advanced Server Limited Edition, which was released in 2001 and runs on 64-bit Intel Itanium microprocessors. All editions of Windows 2000 have common functionality, including many system utilities such as the Microsoft Management Console and standard system management applications such as a disk defragmentation utility. Support for people with disabilities was improved with a number of new assistive technologies, and Microsoft included increased support for different languages and locale information. All versions of the operating system support the Windows NT filesystem, NTFS 5, the Encrypting File System, as well as basic and dynamic disk storage. The Windows 2000 Server family has additional functionality, including the ability to provide Active Directory services (a hierarchical framework of resources), Distributed File System (a file system that supports sharing of files) and fault-redundant storage volumes. Windows 2000 can be installed and deployed to corporate desktops through either an attended or unattended installation. Unattended installations rely on the use of answer files to fill in installation information, and can be performed through a bootable CD using Microsoft Systems Management Server, by the System Preparation Tool.

Microsoft has marketed Windows 2000 as "the most secure Windows we've ever shipped", however it has become the target of a number of high-profile virus attacks such as Code Red and Nimda, and more than six years after its release, continues to receive patches for security vulnerabilities on a near-monthly basis.

History

Windows 2000 is a continuation of the Microsoft Windows NT line of operating systems, replacing its predecessor, Windows NT 4.0. Originally called Windows NT 5, Microsoft changed the name to Windows 2000 on October 27, 1998 It was also the first Windows version that was released without a code name, though Windows 2000 Service Pack 1 was codenamed "Asteroid" and Windows 2000 64-bit was codenamed "Janus" (not to be confused with Windows 3.1, which had the same codename). The first beta for Windows 2000 was released on September 27, 1997 and several further betas were released until Beta 3 which was released on April 29, 1999. From here, Microsoft issued three release candidates between July and November 1999, and finally released the operating system to partners on December 12, 1999. The public received the full version of Windows 2000 on February 17, 2000 and the press immediately hailed it as the most stable operating system Microsoft had ever released. InformationWeek summarized the release "our tests show the successor to NT 4.0 is everything we hoped it would be. Of course, it isn't perfect either." Wired News later described the results of the February launch as "lackluster". Novell was not so impressed with Microsoft's new directory service architecture as they found it to be less scalable or reliable than their own Novell Directory Services (NDS) technology.

Originally, Windows 2000 was planned to replace both Windows 98 and Windows NT 4. However, that was later changed. Instead, an updated version of Windows 98 called Windows 98 Second Edition was released in 1999 as a successor to Windows 98. In 1999, Microsoft started development on a project called Windows Neptune, which was supposed to be a home-user edition of Windows 2000. However, the project lagged in production time – and only one alpha release was built. Windows Me was released as a substitute, and the Neptune project was cancelled in favour of Whistler (Windows XP). The only elements of the Neptune project which were included in Windows 2000 were the ability to upgrade from Windows 95 or Windows 98, and support for the FAT32 file system.

On September 29, 2000, Microsoft released Windows 2000 Datacenter Server, targeted at large-scale computing systems with support for 32 processors.

Four service packs were released for Windows 2000: Service Pack 1 (SP1) on August 15, 2000, Service Pack 2 (SP2) on May 16, 2001, Service Pack 3 (SP3) on August 29, 2002 and its last Service Pack (SP4) on June 26, 2003. Microsoft has stated that they will not release a Service Pack 5, but instead, have made available an "Update Rollup" for Service Pack 4. Microsoft phased out all development of their Java Virtual Machine (JVM) from Windows 2000 in Service Pack 3.

Windows 2000 has since been superseded by newer Microsoft operating systems. Microsoft replaced Windows 2000 Server products with Windows Server 2003, and Windows 2000 Professional with Windows XP Professional.

Architecture

Windows 2000 is a highly modular system that consists of two main layers: a user mode and a kernel mode. The user mode refers to the mode in which user programs are run. Such programs are limited in terms of what system resources they have access to, while the kernel mode has unrestricted access to the system memory and external devices. All user mode applications access system resources through the executive which runs in kernel mode.

User mode

User mode in Windows 2000 is made of subsystems capable of passing I/O requests to the appropriate kernel mode drivers by using the I/O manager. Two subsystems make up the user mode layer of Windows 2000: the environment subsystem and the integral subsystem.

The environment subsystem was designed to run applications written for many different types of operating systems. These applications, however, run at a lower priority than kernel mode processes. There are three main environment subsystems:

1. Win32 subsystem runs 32-bit Windows applications and also supports Virtual DOS Machines (VDMs), which allows MS-DOS and 16-bit Windows 3.x ( Win16) applications to run on Windows.
2. OS/2 environment subsystem supports 16-bit character-based OS/2 applications and emulates OS/2 1.3 and 1.x, but not 32-bit or graphical OS/2 applications as used on OS/2 2.x or later.
3. POSIX environment subsystem supports applications that are strictly written to either the POSIX.1 standard or the related ISO/ IEC standards.

The integral subsystem looks after operating system specific functions on behalf of the environment subsystem. It consists of a security subsystem (grants/denies access and handles logons), workstation service (helps the computer gain network access) and a server service (lets the computer provide network services).

Kernel mode

Kernel mode in Windows 2000 has full access to the hardware and system resources of the computer. The kernel mode stops user mode services and applications from accessing critical areas of the operating system that they should not have access to.

The executive interfaces with all the user mode subsystems. It deals with I/O, object management, security and process management. It contains various components, including:

• Object manager: a special executive subsystem that all other executive subsystems must pass through to gain access to Windows 2000 resources. This is essentially a resource management infrastructure service that allows Windows 2000 to be an object oriented operating system.
• I/O Manager: allows devices to communicate with user-mode subsystems by translating user-mode read and write commands and passing them to device drivers.
• Security Reference Monitor (SRM): the primary authority for enforcing the security rules of the security integral subsystem.
• IPC Manager: short for Interprocess Communication Manager, manages the communication between clients (the environment subsystem) and servers (components of the executive).
• Virtual Memory Manager: manages virtual memory, allowing Windows 2000 to use the hard disk as a primary storage device (although strictly speaking it is secondary storage).
• Process Manager: handles process and thread creation and termination
• PnP Manager: handles Plug and Play and supports device detection and installation at boot time.
• Power Manager: the power manager coordinates power events and generates power IRPs.
• The display system is handled by a device driver contained in Win32k.sys. The Window Manager component of this driver is responsible for drawing windows and menus while the GDI ( graphical device interface) component is responsible for tasks such as drawing lines and curves, rendering fonts and handling palettes.

The Windows 2000 Hardware Abstraction Layer, or HAL, is a layer between the physical hardware of the computer and the rest of the operating system. It was designed to hide differences in hardware and therefore provide a consistent platform to run applications on. The HAL includes hardware specific code that controls I/O interfaces, interrupt controllers and multiple processors.

The hybrid kernel sits between the HAL and the executive and provides multiprocessor synchronization, thread and interrupt scheduling and dispatching, trap handling and exception dispatching. The hybrid kernel often interfaces with the process manager and is responsible for initialising device drivers at bootup that are necessary to get the operating system up and running.

Common functionality

Certain features are common across all editions of Windows 2000, among them being NTFS 5, the Microsoft Management Console (MMC), the Encrypting File System (EFS), dynamic and basic disk storage, usability enhancements and multi-language and locale support. Windows 2000 also has several standard system utilities included as standard. As well as these features, Microsoft introduced a new feature to protect critical system files, called Windows File Protection. This prevents programs (with the exception of Microsoft's update programs) from replacing critical Windows system files and thus making the system inoperable.

Microsoft recognized that the infamous Blue Screen of Death (or stop error) could cause serious problems for servers that needed to be constantly running and so provided a system setting that would allow the server to automatically reboot when a stop error occurred. Also included is an option to dump any of the first 64 KB of memory to disk (the smallest amount of memory that is useful for debugging purposes, also known as a minidump), a dump of only the kernel's memory, or a dump of the entire contents of memory to disk, as well as write that this event happened to the Windows 2000 event log. In order to improve performance on computers running Windows 2000 as a server operating system, Microsoft gave administrators the choice of optimizing the operating system's memory and processor usage patterns for background services or for applications.

NTFS 5

Microsoft released the third version of the NTFS file system — also known as version 5.0 — as part of Windows 2000; this introduced quotas, file-system-level encryption, sparse files and reparse points. Sparse files allow for the efficient storage of data sets that are very large yet contain many areas that only have zeroes. Reparse points allow the object manager to reset a file namespace lookup and let file system drivers implement changed functionality in a transparent manner. Reparse points are used to implement volume mount points, junctions, Hierarchical Storage Management, Native Structured Storage and Single Instance Storage. Volume mount points and directory junctions allow for a file to be transparently referred from one file or directory location to another.

Encrypting File System

The Encrypting File System (EFS) introduced strong file-level encryption to Windows. It allows any folder or drive on an NTFS volume to be encrypted transparently to the end user. EFS works in conjunction with the EFS service, Microsoft's CryptoAPI and the EFS File System Run-Time Library (FSRTL). As of September 2006, its encryption has not been compromised.

EFS works by encrypting a file with a bulk symmetric key (also known as the File Encryption Key, or FEK), which is used because it takes a relatively smaller amount of time to encrypt and decrypt large amounts of data than if an asymmetric key cipher is used. The symmetric key that is used to encrypt the file is then encrypted with a public key that is associated with the user who encrypted the file, and this encrypted data is stored in the header of the encrypted file. To decrypt the file, the file system uses the private key of the user to decrypt the symmetric key that is stored in the file header. It then uses the symmetric key to decrypt the file. Because this is done at the file system level, it is transparent to the user.

Also, in case of a user losing access to their key, support for recovery agents that can decrypt files is built in to EFS.

Basic and dynamic disk storage

Windows 2000 introduced the Logical Disk Manager for dynamic storage. All versions of Windows 2000 support three types of dynamic disk volumes (along with basic storage): simple volumes, spanned volumes and striped volumes:

• Simple volume: this is a volume with disk space from one disk.
• Spanned volumes: multiple disks spanning up to 32 disks. If one disk fails, all data in the volume is lost.
• Striped volumes: also known as RAID-0, a striped volume stores all its data across several disks in stripes. This allows better performance because disk read and writes are balanced across multiple disks.

Windows 2000 also added support for the iSCSI protocol.

Accessibility support

Microsoft made an effort to increase the usability of Windows 2000 for people with visual and auditory impairments and other disabilities. They included several utilities designed to make the system more accessible:

• FilterKeys: These are a group of keyboard related support for people with typing issues, and include:
  • SlowKeys: Windows is told to disregard keystrokes that are not held down for a certain time period
  • BounceKeys: multiple keystrokes to one key to be ignored within a certain timeframe
  • RepeatKeys: allows users to slow down the rate at which keys are repeated via the keyboard's keyrepeat feature
• ToggleKeys: when turned on, Windows will play a sound when either the CAPS LOCK, NUM LOCK or SCROLL LOCK keys are pressed
• MouseKeys: allows the cursor to be moved around the screen via the numeric keypad instead of the mouse
• On screen keyboard: assists those who are not familiar with a given keyboard by allowing them to use a mouse to enter characters to the screen
• SerialKeys: gives Windows 2000 the ability to support speech augmentation devices
• StickyKeys: makes modifier keys (ALT, CTRL and SHIFT) become "sticky" — in other words a user can press the modifier key, release that key and then press the combination key. Normally the modifier key must remain pressed down to activate the sequence. (Activated by pressing Shift 6 times quickly)
• On screen magnifier: assists users with visual impairments by magnifying the part of the screen they place their mouse over.
• Narrator: Microsoft Narrator assists users with visual impairments with system messages, as when these appear the narrator will read this out via the sound system
• High contrast theme: to assist users with visual impairments
• SoundSentry: designed to help users with auditory impairments, Windows 2000 will show a visual effect when a sound is played through the sound system

Language & locale support

Windows 2000 has support for many languages other than English. It supports Arabic, Armenian, Baltic, Central European, Cyrillic, Georgian, Greek, Hebrew, Indic, Japanese, Korean, Simplified Chinese, Thai, Traditional Chinese, Turkic, Vietnamese and Western European languages. It also has support for many different locales, a list of which can be found on Microsoft's website.

Games support

Windows 2000 included version 7.0 of the DirectX application programming interfaces, commonly used by game developers on Windows 98. The majority of games written for recent versions of DirectX could therefore run on Windows 2000, in contrast to Windows NT 4.0, which only provided support for DirectX 3.

System utilities

Windows 2000 introduced the Microsoft Management Console (MMC), which is used to create, save, and open administrative tools. Each of the tools is called a console, and most consoles allow an administrator to administer other Windows 2000 computers from one centralised computer. Each console can contain one or many specific administrative tools, called snap-ins. Snap-ins can be either standalone (performs one function), or extensions (adds functionality to an existing snap-in). In order to provide the ability to control what snap-ins can be seen in a console, the MMC allows consoles to be created in author mode or created in user mode. Author mode allows snap-ins to be added, new windows to be created, all portions of the console tree can be displayed and for consoles to be saved. User mode allows consoles to be distributed with restrictions applied. User mode consoles can have full access granted user so they can make whatever changes they desire, can have limited access so that users cannot add to the console but they can view multiple windows in a console, or they can have limited access so that users cannot add to the console and also cannot view multiple windows in a console.

The main tools that come with Windows 2000 can be found in the Computer Management console (found in Administrative Tools in the Control Panel). This contains the event viewer — a means of seeing events and the Windows equivalent of a log file, a system information viewer, the ability to view open shared folders and shared folder sessions, a device manager and a tool to view all the local users and groups on the Windows 2000 computer. It also contains a disk management snap-in, which contains a disk defragmenter as well as other disk management utilities. Lastly, it also contains a services viewer, which allows users to view all installed services and to stop and start them on demand, as well as configure what those services should do when the computer starts.

Windows 2000 comes bundled with two utilities to edit the Windows registry. One acts like the Windows 9x REGEDIT.EXE program and the other could edit registry permissions in the same manner that Windows NT's REGEDT32.EXE program could. REGEDIT.EXE has a left-side tree view that begins at "My Computer" and lists all loaded hives. REGEDT32.EXE has a left-side tree view, but each hive has its own window, so the tree displays only keys. REGEDIT.EXE represents the three components of a value (its name, type, and data) as separate columns of a table. REGEDT32.EXE represents them as a list of strings. REGEDIT.EXE was written for the Win32 API and supports right-clicking of entries in a tree view to adjust properties and other settings. REGEDT32.EXE was also written for the Win32 API and requires all actions to be performed from the top menu bar. Because REGEDIT.EXE was directly ported from Windows 98, it does not support permission editing (permissions do not exist in Windows 9x). Therefore, the only way to access the full functionality of an NT registry was with REGEDT32.EXE, which uses the older multiple document interface (MDI), which newer versions of regedit do not use. Windows XP was the first system to integrate these two programs into one, adopting the REGEDIT.EXE behaviour with the additional NT functionality.

The System File Checker (SFC) also comes bundled with Windows 2000. It is a command line utility that scans system files and verifies whether they were signed by Microsoft and works in conjunction with the Windows File Protection mechanism. It can also repopulate and repair all the files in the Dllcache folder.

Recovery Console

The Recovery Console is an application that is run from outside the installed copy of Windows and that enables a user to perform maintenance tasks that cannot be run from inside of the installed copy, or cannot be feasibly run from another computer or copy of Windows 2000. It is usually used to recover the system from errors causing booting to fail, which would render other tools useless.

It presents itself as a simple command line interface. The commands are limited to ones for checking and repairing the hard drive(s), repairing boot information (including NTLDR), replacing corrupted system files with fresh copies from the CD, or enabling/disabling services and drivers for the next boot.

The console can be accessed in one of two ways:

1. Starting from the Windows 2000 CD, and choosing to enter the Recovery Console instead of continuing with setup, or
2. Installing the Recovery Console via Winnt32.exe, with the /cmdcons switch. However, the console can then only be used if the system boots to the point where NTLDR can start it.

Server family functionality

The Windows 2000 server family consists of Windows 2000 Server, Windows 2000 Advanced Server and Windows 2000 Datacenter Server.

All editions of Windows 2000 Server have the following services and functionality built-in:

• Routing and Remote Access Service (RRAS) support, facilitating dial-up and VPN connections, support for RADIUS authentication, network connection sharing, Network Address Translation, unicast and multicast routing
• DNS server, including support for Dynamic DNS. Active Directory relies heavily on DNS.
• Microsoft Connection Manager Administration Kit and Connection Point Services
• Support for distributed file systems (DFS)
• Hierarchical Storage Management support, a service that runs in conjunction with NTFS that automatically transfers files that are not used for some period of time to less expensive storage media
• Fault tolerant volumes, namely it supports Mirrored and RAID-5
• Group policy (part of Active Directory)
• IntelliMirror, a collection of technologies for fine-grained management of Windows 2000 Professional desktops (roaming profiles, software installation, settings management).
• Kerberos authentication
• Public Key Infrastructure (PKI) support
• Terminal Services and support for the Remote Desktop Protocol (RDP)
• Internet Information Server (IIS) 5

Distributed File System

The Distributed File System, or DFS, allows shares in multiple different locations to be logically grouped under one folder, or DFS root. When users try to access a share that exists off the DFS root, the user is really looking at a DFS link and the DFS server transparently redirects them to the correct file server and share. A DFS root can only exist on a Windows 2000 version that is part of the server family, and only one DFS root can exist on that server.

There can be two ways of implementing DFS on Windows 2000: through standalone DFS, or through domain-based DFS. Standalone DFS allows for only DFS roots that exist on the local computer, and thus does not use Active Directory. Domain-based DFS roots exist within Active Directory and can have their information distributed to other domain controllers within the domain — this provides fault tolerance to DFS. DFS roots that exist on a domain must be hosted on a domain controller or on a domain member server. The file and root information is replicated via the Microsoft File Replication Service (FRS).

Active Directory

A new way of organizing Windows network domains, or groups of resources, called Active Directory, was introduced with Windows 2000 and obsoleted Windows NT's traditional domain model. Active Directory's hierarchical nature allowed administrators a built-in way to manage user and computer policies, user accounts, and to automatically deploy programs and updates with a greater degree of scalability and centralization than provided in previous Windows versions. It is one of the main reasons many corporations migrated to Windows 2000. User information stored in Active Directory also provided a convenient phone book-like function to end users. Active Directory domains can vary from small installations with a few hundred objects, to large installations with millions of objects. Active Directory contains the ability to organise and link groups of domains into a contiguous domain name space to form trees. Groups of trees existing outside of the same namespace can be linked together to form forests.

Active Directory services can only be installed on a Windows 2000 Server, Advanced Server, or Datacenter Server computer, and cannot be installed on a Windows 2000 Professional computer. However, Windows 2000 Professional was the first client operating system able to exploit Active Directory's new functionality. As part of an organization's migration, Windows NT clients continued to function until all clients were upgraded to Windows 2000 Professional, at which point the Active Directory domain could be switched to native mode and maximum functionality achieved.

Active directory requires a new DNS server that supports SRV resource records, or that an organization's existing DNS infrastructure be upgraded to support this functionality. It also requires that one or more domain controllers exist to hold the Active Directory database and provide Active Directory directory services.

Volume fault tolerance

Along with support for simple, spanned and striped volumes, the server family of Windows 2000 also supports fault tolerant volume types. The types supported are mirrored volumes and RAID-5 volumes:

• Mirrored volumes: the volume contains several disks, and when data is written to one it is mirrored to the other disks. This means that if one disk fails, the data can be totally recovered from the other disk. Mirrored volumes are also known as RAID-1.
• RAID-5 volumes: a RAID-5 volume consists of multiple disks, and it uses block-level striping with parity data distributed across all member disks. Should a disk fail in the array, the parity blocks from the surviving disks are combined mathematically with the data blocks from the surviving disks to reconstruct the data on the failed drive "on-the-fly" (this works with various levels of success).

Versions

Microsoft released various versions of Windows 2000 to cater to different markets and business needs. It released Windows 2000 Professional, Windows 2000 Server, Windows 2000 Advanced Server and Windows 2000 Datacenter Server:

• Windows 2000 Professional was designed as the desktop operating system for businesses and power users. It is the basic unit of Windows 2000, and the most common. 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 were a Pentium Processor @133MHz or greater, at least 64 MB of RAM, 650 MB of hard drive space, and a CD-ROM drive (recommended: Pentium II, 128 MB of RAM, 1 GB of hard drive space, and CD-ROM drive).
• Windows 2000 Server products share the same user interface with Windows 2000 Professional, but contain additional components for running infrastructure and application software. A significant component of the server products 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 catalogue, being linked with two-way transitive trusts). Furthermore, Windows 2000 introduced a DNS server which allows dynamic registration of IP addresses.
• Windows 2000 Advanced Server 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 has support for TCP/IP load balancing and enhanced two-node server clusters based on the Microsoft Cluster Server (MSCS) in the Windows NT Server 4.0 Enterprise Edition. A limited edition 64 bit version of Windows 2000 Advanced Server was made available via the OEM Channel. It also supports failover and load balancing.
• Windows 2000 Datacenter Server is a variant of the Windows 2000 Server that is designed for large businesses that move large quantities of confidential or sensitive data frequently via a central server. As with Advanced Server, it supports clustering, failover and load balancing. Its system requirements are normal, but are compatible with vast amounts of power:
  • A Pentium-class CPU at 400 MHz or higher - up to 32 are supported in one machine
  • 256 MB of RAM - up to 64 GB is supported in one machine
  • Approximately 1 GB of available disk space

Deployment

Windows 2000 can be deployed to a site via various methods. It can be installed onto servers via traditional media (such as via CD) or via distribution folders that reside on a shared folder. Installations can be attended or unattended. An attended installation requires the manual intervention of an operator to choose options when installing the operating system. Unattended installations are scripted via an answer file, or predefined script in the form of an INI file that has all the options filled in already. The Winnt.exe or Winnt32.exe program then uses that answer file to automate the installation. Unattended installations can be performed via a bootable CD, using Microsoft Systems Management Server (SMS), via the System Preparation Tool (Sysprep), via running the Winnt32.exe program using the /syspart switch or via running the Remote Installation Service (RIS).

The Syspart method is started on a standardised reference computer — though the hardware need not be similar — and it copies the required installation files from the reference computer's hard drive to the target computer's hard drive. The hard drive does not need to be in the target computer and may be swapped out to it at any time, with hardware configuration still needing to be done later. The Winnt.exe program must also be passed a /unattend switch that points to a valid answer file and a /s file to point to the location of one or more valid installation sources.

Sysprep allows the duplication of a disk image on an existing Windows 2000 Server installation to multiple servers. This means that all applications and system configuration settings will be copied across to the new Windows 2000 installations, but it also means that the reference and target computers must have the same HALs, ACPI support, and mass storage devices — though Windows 2000 automatically detects plug and play devices. The primary reason for using Sysprep is for deploying Windows 2000 to a site that has standard hardware and that needs a fast method of installing Windows 2000 to those computers. If a system has different HALs, mass storage devices or ACPI support, then multiple images would need to be maintained.

Systems Management Server can be used to upgrade system to Windows 2000 to multiple systems. Those operating systems that can be upgraded in this process must be running a version of Windows that can be upgraded (Windows NT 3.51, Windows NT 4, Windows 98 and Windows 95 OSR2.x) and those versions must be running the SMS client agent that can receive software installation operations. Using SMS allows installations to happen over a wide geographical area and provides centralised control over upgrades to systems.

Remote Installation Services (RIS) are a means to automatically install Windows 2000 Professional (and not Windows 2000 Server) to a local computer over a network from a central server. Images do not have to support specific hardware configurations and the security settings can be configured after the computer reboots as the service generates a new unique security ID (SID) for the machine. This is required so that local accounts are given the right identifier and do not clash with other Windows 2000 Professional computers on a network. RIS requires that client computers are able to boot over the network via either a network interface card that has a Pre-Boot Execution Environment (PXE) boot ROM installed or that it has a network card installed that is supported by the remote boot disk generator. The remote computer must also meet the Net PC specification. The server that RIS runs on must be Windows 2000 Server and the server must be able to access a network DNS Service, a DHCP service and the Active Directory services.

Total cost of ownership

In October 2002, Microsoft commissioned IDC to determine the total cost of ownership (TCO) for enterprise applications on Windows 2000 versus the TCO of Linux on the same enterprise applications. IDC looked at security and other infrastructure tasks, and Web Serving. According to the report, Windows 2000 had a lower TCO for four infrastructure items and Linux had a lower TCO for web serving. IDC's report was based on telephone interviews of IT executives and managers of 104 North American companies in which they determined what they were using for a specific workload for file, print, security and networking services.

IDC determined that the four areas where Windows 2000 had a better TCO than Linux — over a period of five years for an average organization of 100 employees — were in the use of file, print, network infrastructure and security infrastructure. They determined, however, that Linux had a better TCO than Windows 2000 when it came to web serving. The report also found that the greatest cost was not in the procurement of software and hardware, but in staffing costs and downtime. The report did not take into consideration the impact of downtime to the profitability of the business (although they did apply a 40% productivity factor, in order to recognize that employees are not entirely unproductive during periods of IT infrastructure downtime) though it did find that Linux servers had less unplanned downtime than Windows 2000 Servers. They found that most Linux servers ran less workload per server than Windows 2000 servers and also found that none of the businesses they interviewed used 4-way SMP Linux computers. IDC also did not take into account specific application servers — servers that need low maintenance and are provided by a specific vendor — when they performed their study. The report did emphasise that TCO was only one factor in considering whether to use a particular IT platform, and also noted that as management and server software improved and became better packaged the overall picture that was being shown in their report could change.

Security flaws

A number of potential security issues have been noted in Windows 2000. A common complaint is that "by default, Windows 2000 installations contain numerous potential security problems. Many unneeded services are installed and enabled, and there is no active local security policy". In addition to the choice of insecure defaults, according to SANS, the most common flaws found in the OS are remotely exploitable buffer overflow vulnerabilities . Other flaws in the operating system that have received criticism include the use of vulnerable encryption techniques .

Computer worms first came into the public spotlight during the period where Windows 2000 was the dominant server operating system. Code Red and Code Red II were famous (and highly visible to the worldwide press) worms that exploited vulnerabilities of the indexing service of Windows 2000's Internet Information Services (IIS). In August 2003, two major worms named the Sobig worm and the Blaster worm began to attack millions of Microsoft Windows computers, resulting in the largest down-time and clean-up cost to that date. The 2005 Zotob worm was blamed for security compromises on Windows 2000 machines at Homeland Security, the New York Times, ABC and CNN.

Service Packs

Throughout its life, Windows 2000 has received four full service packs and one rollup update package which is the latest service pack for Windows 2000. Many Windows 2000 users were hoping for a Windows 2000 Service Pack 5, but Microsoft cancelled this project early on in its development. Service pack 5 went on to become Update Rollup 1 for Service Pack 4. Microsoft states that this update will meet customers needs better than a whole new service pack , and will still help Windows 2000 customers secure their PCs, reduce support costs, and allow their systems to support the current generation of computer hardware.

Because Windows 2000 is now in the Extended support phase of the Microsoft Lifecycle Policy there will be no future service packs for Windows 2000. Only critical updates will be provided for Windows 2000 unpaid.