NT Server 5.0 Hardware Specifications

New standards, new guidelines, new features

Over the past 15 years, computer hardware requirements have risen dramatically to accommodate increasingly complex software. Hardware has progressed from the 8086 processor and 64KB of RAM that DOS originally required, to the 80286 processor and 2MB of RAM that Windows 3.1 requires, to the 80386 processor and 16MB of RAM that Windows NT 3.51 required. Not surprisingly, NT 5.0 introduces even higher requirements for memory space, processor speed, and other system resources.

PC98 System Design Guide and Hardware Design Guide for Microsoft Windows NT Server (these guides are from both Microsoft and Intel) present design guidelines for hardware that runs NT 5.0. PC98 System Design Guide describes general requirements for building PCs, peripherals, and add-ons for NT Server 5.0, NT Workstation 5.0, and Windows 98. The Hardware Design Guide focuses on design requirements for systems that will run NT Server 5.0; its information is a subset of PC98 System Design Guide's definitions for next-generation systems. You can view and download both documents at http://www.microsoft.com/hwdev/desguid/default.htm. (The Web site calls the Hardware Design Guide the Windows NT Server System Design Guide.)

Microsoft won't be able to gauge NT 5.0's performance until the release of beta 2, so no one will know NT 5.0's base system requirements until then. Nevertheless, a system that meets the design guides' requirements will offer the best performance with NT 5.0. This article provides an overview of the design guides' specifications for hardware that runs NT Server 5.0, including requirements for CPU speed, RAM space, and other system components. Use this information to prepare for the next NT release.

How Much Functionality Do You Need?
NT 5.0 will run on hardware that doesn't meet PC98 System Design Guide and Hardware Design Guide specifications; these specifications aren't the absolute minimum requirements for running the operating system (OS). Servers that don't meet these guidelines might not support all of NT 5.0's features or deliver optimal performance, but most will support the basic OS. If your system offers good performance under NT 4.0, then it will probably perform adequately under NT 5.0.

The Hardware Design Guide and PC98 System Design Guide recommendations for NT Server 5.0 specify hardware requirements for three system categories: basic server, small office/home office (SOHO) server, and enterprise server. A basic server is a general-purpose platform for use in small businesses or clustered enterprise environments. Basic servers meet baseline requirements for availability, reliability, scalability, and ease of use and administration. A SOHO server is a general-purpose platform tailored to users with limited administrative expertise. SOHO servers' performance focus is on file and print and client/server applications, and SOHO servers can double as workstations. An enterprise server is a system that serves as the foundation for a large organization. Administrators use enterprise servers for mission-critical tasks, such as data storage and email, so these systems require high availability.

Required RAM
Current data shows that, like NT Server 4.0, NT Server 5.0 runs on systems with 16MB of RAM, but if you want to do anything more than watch the logon screen, you need at least 32MB of RAM. The Hardware Design Guide calls for 64MB of RAM for basic servers, but for optimal basic server performance, you might need 128MB of RAM. The Hardware Design Guide requires 128MB of RAM for SOHO servers (256MB of RAM for multiprocessor SOHO systems) and 2GB of RAM for enterprise servers. The absolute minimum RAM requirement for NT Server 5.0 is currently 16MB, but when the final version comes out, Microsoft might set the minimum RAM to 24MB.

The Hardware Design Guide also covers servers' minimum capabilities for RAM expansion. A basic server must allow for at least 512MB of Error-Correcting Code (ECC) RAM, or 256MB per CPU for multiprocessor systems. The requirement that servers have ECC RAM is important for high-availability systems, because the systems' memory and cache must detect and correct for common error conditions. For example, ECC RAM must detect 2-bit word errors and correct single-bit word errors. The Hardware Design Guide recommends but doesn't require that servers detect the failure of one DRAM device (such as a SIMM or DIMM) via a 4-bit or 8-bit word error.

Because of recent advances in chip densities, most enterprise-application servers on the market today hold 2GB or 4GB of RAM. Some servers, such as Digital Equipment's Alpha servers, hold as much as 8GB of RAM, and Sequent and Unisys have proposed systems with 32GB of RAM. So, if you buy a new machine, meeting the RAM requirement won't be a problem. If your organization has only a handful of servers, you can upgrade your servers' RAM without creating a serious financial burden, because memory costs about $2 per MB right now. However, large IS departments that want to migrate to NT 5.0 must seriously consider the cost of RAM upgrades. Distributed organizations with thousands of servers might have to pay as much as $1 million to upgrade their servers' RAM (32MB * $2 per MB * 15,000 servers = $960,000). ECC, Enhanced Data Output (EDO), and standard RAM cost about the same amount (Synchronous DRAM--SDRAM--costs slightly more), so if you're buying new RAM, you might as well buy ECC RAM.

CPUs and Cache
Will you need to upgrade your CPUs? Perhaps. If you're running a 386, you must upgrade to at least a 486, NT Server 5.0's minimum for basic servers, according to the Hardware Design Guide. Therefore, you can't upgrade a DOS or Windows 3.x legacy system that has less than a 486 processor to NT 5.0. Organizations with large numbers of older platforms can use a Windows-terminal approach rather than upgrade all users' desktops. Older systems that have 486 or Pentium CPUs and enough RAM and disk space will probably work fine under NT 5.0, as long as the machines are on Microsoft's Hardware Compatibility List (HCL--http://www.microsoft.com/hwtest/hcl).

Intel no longer manufactures CPUs slower than the Pentium MMX, so if you upgrade, you'll have to upgrade to a Pentium MMX or better CPU. The Hardware Design Guide recommends a Pentium Pro or better, or a RISC processor (Alpha processors only--NT no longer supports MIPS or PowerPC processors). The Hardware Design Guide requires basic and enterprise servers to have at least 200MHz CPUs and requires SOHO servers to have 180MHz CPUs. NT 5.0 doesn't require symmetric multiprocessing (SMP) boxes, but it supports them. Multiprocessing systems must meet Intel's Multiprocessor Specification (MP Spec), version 1.4 or later. All SMP systems available today meet the specification, but some SMP systems from a few years ago don't. Those older systems won't perform well under NT 5.0.

Cache is another important hardware element. The Hardware Design Guide and PC98 System Design Guide specifications don't require cache for basic servers, but you need cache for NT 5.0 to run well. The more cache you have, the better your system will perform. PC98 System Design Guide-compliant machines that use cache must implement Level 2 cache as write-back, which means the cache controller responds immediately to the CPU and later writes transactions to the main memory, rather than writing out transactions before signaling the CPU. Write-back prevents the cache from slowing down the system during periods of high bus traffic. Chips with faster internal buses also improve system performance.

The PC98 System Design Guide and Hardware Design Guide specifications require that each processor on systems with Pentium Pro or better CPUs have its own Level 2 cache. This requirement underscores the importance of independent cache for each CPU. Tests in the Windows NT Magazine Lab (see "HP NetServer 5/166 LS4," May 1996) have demonstrated that computers with 1MB or 2MB off-chip independent cache modules are significantly faster than machines with 512KB shared-cache units. Most machines manufactured today have independent cache for each CPU, but some older systems use shared-cache modules. The Hardware Design Guide requires SOHO server CPUs to have 256KB of Level 2 cache and enterprise server CPUs to have 512KB of Level 2 cache.

Other Features
Many of the technologies PC98 System Design Guide and the Hardware Design Guide describe have been around for years. By including these technologies in the NT 5.0 specifications, Microsoft has added them to the list of technologies NT officially supports. (For more information about new hardware that NT 5.0 supports, including Advanced Configuration and Power Interface--ACPI, Universal Serial Bus--USB, and Intelligent Input/Output--I2O, see Nik Simpson, "Business Server Development and NT 5.0," page 117.)

When you're shopping for a new machine that will run NT 5.0, your first search criterion needs to be finding a system that doesn't have an ISA bus. Basic and enterprise servers can include ISA slots, but the primary expansion controllers for your disks, network, and video output cannot reside in them. SOHO servers must not contain ISA expansion slots. When you purchase new peripherals, look for devices with 32-bit tuned drivers and adapter cards that support bus mastering and Plug and Play (PnP). When you buy a server, look for a system that has the following features.

System bus. Your new system needs a bridged dual-bus PCI architecture. Such an architecture lets you place a system's NIC and disk controller on separate buses to achieve higher aggregate data throughput (264MB per second--MBps--or faster). In addition to the bridged dual-bus architecture, look for a system with a 64-bit, 66MHz PCI bus, even if the system also includes a 32-bit bus. Look for a server that has a motherboard with an onboard PCI-based VGA controller and the capability to hot-swap ACPI devices.

You need to look at your new system's device drivers. To be compatible with the Hardware Design Guide, drivers must meet several criteria. They must be fully 32-bit. They must store configuration settings in the Registry, rather than in .ini files. You need to be able to use Windows-based methods for installing and removing drivers from the hard disk. The drivers must let you use scripts to perform unattended device setups. They must use unique filenames and come with Help files. They must support PnP and power management I/O request packets. Drivers that are Windows Driver Model (WDM)-compliant need to be WDM mini-drivers. Finally, your drivers must not support real-mode or 16-bit protected-mode operation; they must support only 32-bit protected-mode operation. (This limitation is one reason why software can't write directly to hardware in any version of NT.)

If you're planning to buy a new server, look for a system bus feature that isn't part of either NT 5.0 specification: Intel's new 100MHz system bus. The 100MHz bus improves the architecture's ability to support the forthcoming 450MHz Pentium II CPUs and next year's 8-way Slot 2 Deschutes designs.

Network components. NT Server is a network OS (NOS), so the OS derives its power from the network standards and devices it supports. The network device interface specification (NDIS) 5.0 defines NT 5.0's variations from the NDIS 3.0 and NDIS 4.0 networking standards. NDIS 5.0's list of the networking capabilities that NT 5.0 supports includes PnP, new driver architecture, network power management, Windows hardware instrumentation, and task offload of TCP/IP checksum (error detection) and Point-to-Point Protocol (PPP) compression and encryption. NDIS 5.0 also includes broadcast media extensions for use with broadcast components such as TV cards. It includes support for asynchronous transfer mode (ATM); asymmetric digital subscriber line (ADSL); streaming media; Quality of Service (QOS--for example, guaranteed bandwidth); and intermediate driver support for features including broadcast, Virtual LANs (VLANs), and LAN emulation over media such as ATM, television, and FireWire (IEEE 1394). (For more information about NDIS 5.0, see http://www.microsoft.com/hwdev/devdes/ndis5.htm.)

The Hardware Design Guide recommends that servers have a NIC that is also an integrated hub with five or more non-ISA ports. The NIC needs to automatically detect the carrier mode (e.g., full- or half-duplex) and carrier speed (e.g., 10 megabits per second­Mbps­or 100Mbps) and change the NIC configuration to match. The NIC also needs to have automatic hub, switch, or router detection; automatic transceiver type detection; the ability to communicate with drivers across a PCI bridge adapter; filtering for at least 32 simultaneous multicast addresses (for push technologies such as NetShow, Active Desktop, and Internet Explorer--IE--4.0); support for performance tuning and configuration through the Registry; BIOS boot; and Dynamic Host Configuration Protocol (DHCP) and Trivial File Transfer Protocol (TFTP) support for remote system setup. The Hardware Design Guide also outlines requirements for modems and interfaces for ATM, ADSL, and ISDN.

Storage devices. PC98 System Design Guide and Hardware Design Guide guidelines for storage devices cover Digital Versatile Disc (DVD), rewriteable CD-ROMs, and high-capacity hard disks. The guidelines call for non-ISA, low-latency (i.e., with low seek and access times) high-speed devices (capable of 20MBps to 40MBps data transfer rates) with full SCSI-3 support. A system that meets the basic server requirements must also have SCSI embedded on the motherboard.

The NT Server 5.0 specifications require servers to support a variety of storage devices. They specify that servers' SCSI devices must be PnP adapters that clearly identify the connectors to prevent incorrect attachment. SCSI devices must offer differential SCSI support, automatic and built-in termination, an external SCSI-2 connector, and start/stop support to decrease power consumption. The Hardware Design Guide calls for enterprise servers to have 40MBps to 80MBps SCSI disks (100MBps with fibre channel).

The Hardware Design Guide specifies that servers must not have ISA-based IDE. The guide recommends that servers not use IDE but provides specifications for servers that do use IDE. The specifications state these servers must comply with ATA-2, have dual PCI IDE adapters, offer logical block addressing to support drives larger than 528MB, provide support for bus mastering, and comply with the Self-Monitoring Analysis and Reporting Technology (S.M.A.R.T.) standard.

The NT 5.0 server specifications recommend fibre channel technology. Fibre channel allows for 1 gigabit (Gb) per second data transfer rates for SCSI and IP. (For more information about fibre channel, see Dean Porter, "Fibre Channel, SCSI, and You," September 1997.)

The CD-ROM specifications for NT 5.0 are similar to those for NT 4.0, but they recommend a minimum speed of 8X, erasable media, and bootable CD-ROM capability. DVD drives must support bus-mastering direct memory access (DMA) transfers, Universal Disk Format (UDF), and push-to-close design; include a high-speed bus that supports multiple data types and sustained rates of 12Mbps; and support video playback standards, such as MPEG-2 and AC-3.

The Hardware Design Guide recommends that every system include a tape drive and requires systems that include tape drives to use SCSI-based tapes that hold at least 4GB and reach speeds of 20MB per minute. The guidelines require enterprise servers to include 8GB tape drives.

Physical design. Server components need to be easy to access, so the Hardware Design Guide lays out requirements for server cases' physical attributes. These requirements include keyed, shrouded, and snap-on connectors; easily distinguishable, visible icons on the outside of the case; easy-to-access expansion slots; covered switches; a locking case; and snap-on connectors.

Trusted Computer System Evaluation Criteria, which the US Department of Defense's National Computer Security Center publishes, defines requirements for C2-compatible hardware. External drives must lock. The case and switches must lock. The system must support remote software management of physical components. The computer must include software controls for monitoring system status and remote alerts that notify administrators when an intruder opens the chassis, and it must provide smart card readers.

Reliability and manageability. The Hardware Design Guide requires servers to have an integrated backup device. The specification recommends hot-swappable N+1 power supplies and companion UPSs, and requires enterprise servers to have hot-swappable power supplies.

For fault tolerance, the Hardware Design Guide requires multiple hot-swappable hard disks and an intelligent RAID controller with support for RAID 1, 5, or 1/0. The RAID controller must provide notification of disk failures and automatically reconfigure a RAID volume for a replacement or available hot-spare disk. Enterprise servers must have an intelligent RAID controller (level 1, 5, or 1/0).

Systems must provide alert indicators for notification about failures or imminent failure of major system components. Enterprise servers must also include hot-swappable fans.

The Hardware Design Guide requires servers to supply Web-Based Enterprise Management (WBEM) and Common Interface Model (CIM) schemas for management browsers, support Windows Management Instrumentation (WMI)-enabled mini-drivers, and offer remote device management. (For more information about WBEM and CIM, see Greg Todd, "What Is WBEM?" July 1998). To avoid Year 2000 (Y2K) problems, the Hardware Design Guide calls for servers to have BIOS, realtime clocks, and CMOS that will function correctly into the new millennium.

Buying the Hardware
Some systems manufacturers already offer servers that meet the Hardware Design Guide and PC98 System Design Guide specifications, and many more will produce compatible servers before NT 5.0's release. You're better off buying a complete system from a vendor that offers comprehensive support (including services, software, and drivers) and guarantees its products than trying to build a system to support NT 5.0. You'll pay more for a complete system than for a system your IS staff builds, but buying a system you can rely on to support NT 5.0's new features makes sense. Use the sidebar "Buying Your Box" to determine exactly what type of system you'll need to provide the performance you want, and make sure your systems meet the Hardware Design Guide and PC98 System Design Guide specifications.