NetWare is a
network operating systemA networking operating system , also referred to as the Dialoguer, is the software that runs on a server and enables the server to manage data, users, groups, security, applications, and other networking functions...
developed by Novell, Inc. It initially used cooperative multitasking to run various services on a
personal computerA personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
, with network protocols based on the archetypal
XeroxXerox Corporation is an American multinational document management corporation that produced and sells a range of color and black-and-white printers, multifunction systems, photo copiers, digital production printing presses, and related consulting services and supplies...
Network Systems
stackThe protocol stack is an implementation of a computer networking protocol suite. The terms are often used interchangeably. Strictly speaking, the suite is the definition of the protocols, and the stack is the software implementation of them....
.
Novell superseded NetWare with
Open Enterprise ServerNovell Open Enterprise Server is the successor product to Novell, Inc.'s NetWare operating system, based on SUSE Linux Enterprise Server . Originally released in March 2005, the current release is OES 2 SP3...
(OES) in 2005. The latest version of NetWare is v6.5 Support Pack 8, which is identical to OES 2 SP1, NetWare Kernel.
History
NetWare evolved from a very simple concept: file sharing instead of disk sharing. In 1983 when the first versions of NetWare originated, all other competing products were based on the concept of providing shared direct disk access. Novell's alternative approach was validated by
IBMInternational Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...
in 1984, which helped promote the NetWare product.
Novell NetWare shared disk-space in the form of NetWare
volumes, comparable to DOS volumes. Clients running
MS-DOSMS-DOS is an operating system for x86-based personal computers. It was the most commonly used member of the DOS family of operating systems, and was the main operating system for IBM PC compatible personal computers during the 1980s to the mid 1990s, until it was gradually superseded by operating...
would run a special
terminate and stay residentTerminate and Stay Resident is a computer system call in DOS computer operating systems that returns control to the system as if the program has quit, but keeps the program in memory...
(TSR) program that allowed them to
map a local drive letter to a NetWare volume. Clients had to log in to a server in order to be allowed to map volumes, and access could be restricted according to the login name. Similarly, they could connect to shared printers on the dedicated server, and print as if the printer was connected locally.
At the end of the 1990s, with
InternetThe Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...
connectivity booming, the Internet's TCP/IP protocol became dominant on
LANA local area network is a computer network that interconnects computers in a limited area such as a home, school, computer laboratory, or office building...
s. Novell had introduced limited TCP/IP support in NetWare v3.x (circa 1992) and v4.x (circa 1995), consisting mainly of FTP services and UNIX-style LPR/LPD printing (available in NetWare v3.x), and a Novell-developed webserver (in NetWare v4.x). Native TCP/IP support for the client file and print services normally associated with NetWare was introduced in NetWare v5.0 (released in 1998).
During the early-to-mid 1980s
MicrosoftMicrosoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
introduced their own LAN system in
LAN ManagerLAN Manager was a Network Operating System available from multiple vendors and developed by Microsoft in cooperation with 3Com Corporation. It was designed to succeed 3Com's 3+Share network server software which ran atop a heavily modified version of MS-DOS.-Development history:LAN Manager was...
, based on the competing NBF protocol. Early attempts to muscle in on NetWare failed, but this changed with the inclusion of improved networking support in Windows for Workgroups, and then the hugely successful
Windows NTWindows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. It was a powerful high-level-language-based, processor-independent, multiprocessing, multiuser operating system with features comparable to Unix. It was intended to complement...
and
Windows 95Windows 95 is a consumer-oriented graphical user interface-based operating system. It was released on August 24, 1995 by Microsoft, and was a significant progression from the company's previous Windows products...
. NT, in particular, offered services similar to those offered by NetWare, but on a system that could also be used on a desktop, and connected directly to other Windows desktops where NBF was now almost universal.
The rise of NetWare
The popular use and growth of Novell NetWare began in 1985 with the simultaneous release of NetWare 286 2.0a and the
Intel 80286The Intel 80286 , introduced on 1 February 1982, was a 16-bit x86 microprocessor with 134,000 transistors. Like its contemporary simpler cousin, the 80186, it could correctly execute most software written for the earlier Intel 8086 and 8088...
16-bit processor. The 80286 CPU featured a new 16-bit protected mode that provided access to up to 16 MB RAM as well as new mechanisms to aid multi-tasking. (Prior to the 80286, PC CPU servers used the Intel 8086/8088 8/16-bit processors, which were limited to an address space of 1MB with not more than 640 KB of directly addressable RAM.)
The combination of a higher 16 MB RAM limit, 80286 processor feature utilization, and 256 MB NetWare volume size limit (compared to the 32 MB that MS-DOS allowed at that time) allowed the building of reliable, cost-effective server-based local area networks for the first time. The 16 MB RAM limit was especially important, since it made enough RAM available for disk caching to significantly improve performance. This became the key to Novell's performance while also allowing larger networks to be built.
In another significant innovation, NetWare 286 was hardware-independent, unlike competing server systems from 3Com. Novell servers could be assembled using any brand system with an Intel 80286 or higher CPU, any
MFMModified Frequency Modulation, commonly MFM, is a line coding scheme used to encode the actual data-bits on most floppy disk formats, hardware examples include Amiga, most CP/M machines as well as IBM PC compatibles. Early hard disk drives also used this coding.MFM is a modification to the original...
,
RLLRun length limited or RLL coding is a line coding technique that is used to send arbitrary data over a communications channel with bandwidth limits. This is used in both telecommunication and storage systems which move a medium past a fixed head. Specifically, RLL bounds the length of stretches ...
,
ESDIEnhanced Small Disk Interface was a disk interface designed by Maxtor Corporation in the early 1980s to be a follow-on to the ST-506 interface...
, or
SCSISmall Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, and electrical and optical interfaces. SCSI is most commonly used for hard disks and tape drives, but it...
hard drive and any 8- or 16-bit network adapter for which NetWare drivers were available.
Novell also designed a compact and simple DOS-client software program that allowed DOS stations to connect to a server and access the shared-server hard drive. While the NetWare server file system introduced a new, proprietary file-system design, it looked like a standard DOS volume to the workstation, ensuring compatibility with all existing DOS programs.
Early years
NetWare originated from consulting work by SuperSet Software, a group founded by the friends
Drew MajorDrew Major was one of the founders of Novell and the lead architect and developer of NetWare operating system for over 15 years. In 1981 Drew and his partners Kyle Powell, Dale Neibaur, and Mark Hurst saw value in enabling PCs to share files and other resources via a local area network...
, Dale Neibaur, Kyle Powell and later Mark Hurst. This work stemmed from their classwork at
Brigham Young UniversityBrigham Young University is a private university located in Provo, Utah. It is owned and operated by The Church of Jesus Christ of Latter-day Saints , and is the United States' largest religious university and third-largest private university.Approximately 98% of the university's 34,000 students...
in
Provo, UtahProvo is the third largest city in the U.S. state of Utah, located about south of Salt Lake City along the Wasatch Front. Provo is the county seat of Utah County and lies between the cities of Orem to the north and Springville to the south...
, starting in October 1981.
In 1983,
Raymond Noorda engaged the work by the SuperSet team. The team was originally assigned to create a
CP/MCP/M was a mass-market operating system created for Intel 8080/85 based microcomputers by Gary Kildall of Digital Research, Inc...
disk sharing system to help network the CP/M hardware that Novell sold at the time. The team was privately convinced that CP/M was a doomed platform and instead came up with a successful file-sharing system for the newly introduced IBM-compatible
PCA personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
. They also wrote an application called Snipes - a text-mode game - and used it to test the new network and demonstrate its capabilities. Snipes was the first network application ever written for a commercial personal computer, and it is recognized as one of the precursors of many popular multiplayer games such as
Doom and
Quake.
This
network operating systemA networking operating system , also referred to as the Dialoguer, is the software that runs on a server and enables the server to manage data, users, groups, security, applications, and other networking functions...
(NOS) was later called Novell NetWare. NetWare was based on the
NetWare Core ProtocolThe NetWare Core Protocol is a network protocol used in some products from Novell, Inc. It is usually associated with the NetWare operating system, but parts of it have been implemented on other platforms such as Linux, Windows NT and various flavors of Unix.It is used to access file, print,...
(NCP), which is a packet-based protocol that enables a client to send requests to and receive replies from a NetWare server. Initially NCP was directly tied to the
IPX/SPXIPX/SPX stands for Internetwork Packet Exchange/Sequenced Packet Exchange. IPX and SPX are networking protocols used primarily on networks using the Novell NetWare operating systems.-Protocol Layers:...
protocol, and NetWare communicated natively using only IPX/SPX.
The first product to bear the NetWare name was released in 1983. It was called NetWare 68 (aka
S-NetS-Net was a network operating system and the set of network protocols it used to talk to client machines on the network. Released by Novell in 1983, the S-Net operating system was an entirely proprietary operating system written for the Motorola 68000 processor. It used a star network...
); it ran on the
MotorolaMotorola, Inc. was an American multinational telecommunications company based in Schaumburg, Illinois, which was eventually divided into two independent public companies, Motorola Mobility and Motorola Solutions on January 4, 2011, after losing $4.3 billion from 2007 to 2009...
68000 processor on a proprietary Novell-built file server and used a star
network topologyNetwork topology is the layout pattern of interconnections of the various elements of a computer or biological network....
. This was soon joined by NetWare 86 V4.x, which was written for the
Intel 8086The 8086 is a 16-bit microprocessor chip designed by Intel between early 1976 and mid-1978, when it was released. The 8086 gave rise to the x86 architecture of Intel's future processors...
. This was replaced in 1985 with Advanced NetWare 86 version 1.0a which allowed more than one server on the same network. In 1986, after the
Intel 80286The Intel 80286 , introduced on 1 February 1982, was a 16-bit x86 microprocessor with 134,000 transistors. Like its contemporary simpler cousin, the 80186, it could correctly execute most software written for the earlier Intel 8086 and 8088...
processor became available, Novell released Advanced NetWare 286 V1.0a and subsequently V2.0B (that used IPX routing to allow up to 4 network cards in a server). In 1989, with the
Intel 80386The Intel 80386, also known as the i386, or just 386, was a 32-bit microprocessor introduced by Intel in 1985. The first versions had 275,000 transistors and were used as the central processing unit of many workstations and high-end personal computers of the time...
available, Novell released NetWare 386. Later Novell consolidated the numbering of their NetWare releases, with NetWare 386 becoming NetWare 3.x.
NetWare 286 2.x
NetWare version 2 had a reputation as notoriously difficult to configure, since the operating system was provided as a set of compiled object modules that required configuration and linking. Compounding this inconvenience was that the process was designed to run from multiple diskettes, which was slow and unreliable. Any change to the operating system required a re-linking of the kernel and a reboot of the system, requiring at least 20 diskette swaps. An additional complication in early versions was that the installation contained a proprietary low-level format program for
MFMModified Frequency Modulation, commonly MFM, is a line coding scheme used to encode the actual data-bits on most floppy disk formats, hardware examples include Amiga, most CP/M machines as well as IBM PC compatibles. Early hard disk drives also used this coding.MFM is a modification to the original...
hard drives, which was run automatically before the software could be loaded, called COMPSURF.
NetWare was administered using text-based utilities such as SYSCON. The file system used by NetWare 2 was
NetWare File SystemIn computing, a NetWare File System is a file system based on a heavily-modified version of FAT. It was used in the Novell NetWare operating system. It is the default and only file system for all volumes in versions 2.x through 4.x, and the default and only file system for the SYS volume...
286, or NWFS 286, supporting volumes of up to 256 MB. NetWare 286 recognized 80286
protected modeIn computing, protected mode, also called protected virtual address mode, is an operational mode of x86-compatible central processing units...
, extending NetWare's support of RAM from 1 MB to the full 16 MB addressable by the 80286. A minimum of 2 MB was required to start up the operating system; any additional RAM was used for FAT, DET and file caching. Since 16-bit protected mode was implemented the i80286 and every subsequent Intel x86 processor, NetWare 286 version 2.x would run on any 80286 or later compatible processor.
NetWare 2 implemented a number of features inspired by
mainframeMainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...
and
minicomputerA minicomputer is a class of multi-user computers that lies in the middle range of the computing spectrum, in between the largest multi-user systems and the smallest single-user systems...
systems that were not available in other operating systems of the day. The
System Fault Tolerance (SFT)System Fault Tolerance is a fault tolerant system built into Netware operating systems. There are three levels of fault tolerance:* SFT I 'Hot Fix' maps out bad disk blocks on the file system level to help ensure data integrity * SFT II is a disk mirroring or duplexing system based on RAID 1;...
features included standard read-after-write verification (SFT-I) with on-the-fly bad block re-mapping (at the time, disks did not have that feature built in) and software RAID1 (disk mirroring, SFT-II). The Transaction Tracking System (TTS) optionally protected files against incomplete updates. For single files, this required only a file attribute to be set. Transactions over multiple files and controlled roll-backs were possible by programming to the TTS API.
NetWare 286 2.x supported two modes of operation: dedicated and non-dedicated. In dedicated mode, the server used DOS only as a boot loader to execute the operating system file net$os.exe. All memory was allocated to NetWare; no DOS ran on the server. For non-dedicated operation, DOS 3.3 or higher would remain in memory, and the processor would time-slice between the DOS and NetWare programs, allowing the server computer to be used simultaneously as a network file-server and as a user workstation. All
extended memoryIn DOS memory management, extended memory refers to memory above the first megabyte of address space in an IBM PC or compatible with an 80286 or later processor. The term is mainly used under the DOS and Windows operating systems...
(RAM above 1 MB) was allocated to NetWare, so DOS was limited to only 640kB;
expanded memoryIn DOS memory management, expanded memory is a system of bank switching introduced April 24, 1985 that provided additional memory to DOS programs beyond the limit of conventional memory. Expanded memory uses parts of the address space normally dedicated to communication with peripherals for program...
managers that used the MMU of 80386 and higher processors, such as EMM386, would not work either, because NetWare 286 had control of protected mode and the upper RAM, both of which were required for DOS to use this approach to
expanded memoryIn DOS memory management, expanded memory is a system of bank switching introduced April 24, 1985 that provided additional memory to DOS programs beyond the limit of conventional memory. Expanded memory uses parts of the address space normally dedicated to communication with peripherals for program...
; 8086-style expanded memory on dedicated plug-in cards was possible however. Time slicing was accomplished using the keyboard
interruptIn computing, an interrupt is an asynchronous signal indicating the need for attention or a synchronous event in software indicating the need for a change in execution....
. This feature required strict compliance with the IBM PC design model, otherwise performance was affected. Non-dedicated NetWare was popular on small networks, although it was more susceptible to lockups due to DOS program problems. In some implementations, users would experience significant network slowdown when someone was using the console as a workstation. NetWare 386 3.x and later supported only dedicated operation.
Server licensing on early versions of NetWare 286 was accomplished by using a key card. The key card was designed for an 8-bit ISA bus, and had a serial number encoded on a ROM chip. The serial number had to match the serial number of the NetWare software running on the server. To broaden the hardware base, particularly to machines using the IBM MCA bus, later versions of NetWare 2.x did not require the key card; serialised license floppy disks were used in place of the key cards.
NetWare 3.x
Starting with NetWare 3.x, support for 32-bit
protected modeIn computing, protected mode, also called protected virtual address mode, is an operational mode of x86-compatible central processing units...
was added, eliminating the 16 MB memory limit of NetWare 286. This allowed larger hard drives to be supported, since NetWare 3.x cached (copied) the entire
file allocation tableFile Allocation Table is a computer file system architecture now widely used on many computer systems and most memory cards, such as those used with digital cameras. FAT file systems are commonly found on floppy disks, flash memory cards, digital cameras, and many other portable devices because of...
(FAT) and directory entry table (DET) into memory for improved performance.
By accident or design, the initial releases of the client TSR programs modified the high 16 bits of the 32-bit 80386 registers, making them unusable by any other program until this was fixed.
Phil KatzPhillip Walter Katz was a computer programmer best known as the co-creator of the zip file format for data compression, and the author of PKZIP, a program for creating zip files which ran under DOS.- Career :...
noticed the problem and added a switch to his
PKZIPPKZIP is an archiving tool originally written by Phil Katz and marketed by his company PKWARE, Inc. The common "PK" prefix used in both PKZIP and PKWARE stands for "Phil Katz".-History:...
suite of programs to enable 32-bit register use only when the NetWare TSRs were not present.
NetWare version 3 eased development and administration by modularization. Each functionality was controlled by a software module called a
NetWare Loadable Module (NLM) loaded either at startup or when it was needed. It was then possible to add functionality such as anti-virus software, backup software, database and web servers, long name support (standard filenames were limited to 8 characters plus a three letter extension, matching
MS-DOSMS-DOS is an operating system for x86-based personal computers. It was the most commonly used member of the DOS family of operating systems, and was the main operating system for IBM PC compatible personal computers during the 1980s to the mid 1990s, until it was gradually superseded by operating...
) or Macintosh style files.
NetWare continued to be administered using console-based utilities. The file system introduced by NetWare 3.x and used by default until NetWare 5.x was
NetWare File SystemIn computing, a NetWare File System is a file system based on a heavily-modified version of FAT. It was used in the Novell NetWare operating system. It is the default and only file system for all volumes in versions 2.x through 4.x, and the default and only file system for the SYS volume...
386, or NWFS 386, which significantly extended volume capacity (1 TB, 4 GB files) and could handle up to 16 volume segments spanning multiple physical disk drives. Volume segments could be added while the server was in use and the volume was mounted, allowing a server to be expanded without interruption.
Initially, NetWare used
Bindery services for authentication. This was a stand-alone database system where all user access and security data resided individually on each server. When an infrastructure contained more than one server, users had to log-in to each of them individually, and each server had to be configured with the list of all allowed users.
The "NetWare Name Services" product allowed user data to be extended across multiple servers, and the Windows "Domain" concept is functionally equivalent to NetWare v3.x Bindery services with NetWare Name Services added on (e.g. a 2-dimensional database, with a flat namespace and a static schema).
For a while, Novell also marketed an
OEMAn original equipment manufacturer, or OEM, manufactures products or components that are purchased by a company and retailed under that purchasing company's brand name. OEM refers to the company that originally manufactured the product. When referring to automotive parts, OEM designates a...
version of NetWare 3, called
Portable NetWare, together with OEMs such as
Hewlett-PackardHewlett-Packard Company or HP is an American multinational information technology corporation headquartered in Palo Alto, California, USA that provides products, technologies, softwares, solutions and services to consumers, small- and medium-sized businesses and large enterprises, including...
,
DECDigital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...
and
Data GeneralData General was one of the first minicomputer firms from the late 1960s. Three of the four founders were former employees of Digital Equipment Corporation. Their first product, the Data General Nova, was a 16-bit minicomputer...
, who ported Novell source code to run on top of their Unix operating systems. Portable NetWare did not sell well.
While NetWare 3.x was current, Novell introduced its first high-availability clustering system, named
NetWare SFT-III, which allowed a logical server to be completely mirrored to a separate physical machine. Implemented as a
shared-nothingA shared nothing architecture is a distributed computing architecture in which each node is independent and self-sufficient, and there is no single point of contention across the system...
cluster, under SFT-III the OS was logically split into an interrupt-driven
I/O engine and the event-driven OS core. The I/O engines serialized their interrupts (disk, network etc.) into a combined event stream that was fed to two identical copies of the system engine through a fast (typically 100 Mbit/s) inter-server link. Because of its non-preemptive nature, the OS core, stripped of non-deterministic I/O, behaves deterministically, like a large
finite state machineA finite-state machine or finite-state automaton , or simply a state machine, is a mathematical model used to design computer programs and digital logic circuits. It is conceived as an abstract machine that can be in one of a finite number of states...
.
The outputs of the two system engines were compared to ensure proper operation, and two copies fed back to the I/O engines. Using the existing SFT-II software RAID functionality present in the core, disks could be mirrored between the two machines without special hardware. The two machines could be separated as far as the server-to-server link would permit. In case of a server or disk failure, the surviving server could take over client sessions transparently after a short pause since it had full state information and did not, for example, have to re-mount the volumes - a process at which NetWare was notoriously slow. SFT-III was the first NetWare version able to make use of
SMPIn computing, symmetric multiprocessing involves a multiprocessor computer hardware architecture where two or more identical processors are connected to a single shared main memory and are controlled by a single OS instance. Most common multiprocessor systems today use an SMP architecture...
hardware - the I/O engine could optionally be run on its own CPU. The modern incarnation of NetWare's clustering, Novell Cluster Services (introduced in NetWare v5.0), is very different from SFT-III. NetWare SFT-III, ahead of its time in several ways, was a mixed success.
Novell designed NetWare 386 3.x to run all applications on the server at the same level of processor
memory protectionMemory protection is a way to control memory access rights on a computer, and is a part of most modern operating systems. The main purpose of memory protection is to prevent a process from accessing memory that has not been allocated to it. This prevents a bug within a process from affecting...
, known as "ring 0". While this provided the best possible performance, it sacrificed reliability. The result was that crashes (known as
abends, short for
abnormal ends) were possible and would result in stopping the system. Starting with NetWare 5.x, software modules (NetWare Loadable Modules or NLM's) could be assigned to run in different processor protection rings, ensuring that a software error would not crash the system.
NetWare 4.x
Version 4 in 1993 also introduced NetWare Directory Services, later re-branded as Novell Directory Services (NDS), based on
X.500X.500 is a series of computer networking standards covering electronic directory services. The X.500 series was developed by ITU-T, formerly known as CCITT, and first approved in 1988. The directory services were developed in order to support the requirements of X.400 electronic mail exchange and...
, which replaced the Bindery with a global
directory serviceA directory service is the software system that stores, organizes and provides access to information in a directory. In software engineering, a directory is a map between names and values. It allows the lookup of values given a name, similar to a dictionary...
, in which the infrastructure was described and managed in a single place. Additionally, NDS provided an extensible
schemaA database schema of a database system is its structure described in a formal language supported by the database management system and refers to the organization of data to create a blueprint of how a database will be constructed...
, allowing the introduction of new object types. This allowed a single user authentication to NDS to govern access to any server in the directory tree structure. Users could therefore access network resources no matter on which server they resided, although user license counts were still tied to individual servers. (Large enterprises could opt for a license model giving them essentially unlimited per-server users if they let Novell audit their total user count)
Version 4 also introduced a number of useful tools and features, such as transparent compression at file system level and RSA public/private
encryptionIn cryptography, encryption is the process of transforming information using an algorithm to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key. The result of the process is encrypted information...
.
Another new feature was the NetWare Asynchronous Services Interface (NASI). It allowed network sharing of multiple serial devices, such as modems. Client port redirection occurred via an
MS-DOSMS-DOS is an operating system for x86-based personal computers. It was the most commonly used member of the DOS family of operating systems, and was the main operating system for IBM PC compatible personal computers during the 1980s to the mid 1990s, until it was gradually superseded by operating...
or
Microsoft WindowsMicrosoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
driver allowing companies to consolidate modems and
analog phonePlain old telephone service is the voice-grade telephone service that remains the basic form of residential and small business service connection to the telephone network in many parts of the world....
lines.
The upgrade was not without its flaws- initially NetWare 4 could not coexist with earlier versions on the same network because of incompatibilities.
NetWare for OS/2
Promised as early as 1988, when the Microsoft-IBM collaboration was still ongoing and Microsoft OS/2 was still a fairly limited 16-bit product, the product didn´t become commercially available until IBM and Microsoft had parted ways and IBM had turned OS/2 into a 32-bit, pre-emptive multitasking and multithreading OS.
By August, 1993 Novell released its first version of "Netware for OS/2". This first release supported OS/2 2.1 (1993) as the base OS, and required that users first buy and install IBM OS/2, then purchase NetWare 4.01, and then install the NetWare for OS/2 product. It retailed for $200.
By around 1995, and coincidental with IBM´s renewed marketing push for its 32-bit OS/2 Warp OS, both as a desktop client and as a LAN server (OS/2 Warp Server), NetWare for OS/2 began receiving some good press coverage. "NetWare 4.1 for OS/2" allowed to run Novell´s network stack and server modules on top of IBM´s 32-bit kernel and network stack. It was basically NetWare 4.x running as a service on top of OS/2. It was compatible with third party client and server utilities and NetWare Loadable Modules
http://www.informationweek.com/537/37olnt2.htm.
Since IBM´s 32-bit OS/2 included Netbios, IPX/SPX and TCP/IP support, this means that sysadmins could run all three most popular network stacks on a single box, and use the OS/2 box as a workstation too. NetWare for OS/2 shared memory on the system with OS/2 seamlessly. The book "Client Server survival Guide with OS/2" described it as "glue code that lets the unmodified NetWare 4.x server program think it owns all resources on a OS/2 system". It also claimed that a NetWare server running on top of OS/2 only suffered a 5% to 10% overhead over NetWare running over the bare metal hardware, while gaining OS/2´s pre-emptive multitasking and object oriented GUI.
Novell continued releasing bugfixes and updates to NetWare for OS/2 up to 1998
Strategic mistakes
Novell's strategy with NetWare 286 2.x and 3.x proved very successful; before the arrival of
Windows NTWindows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. It was a powerful high-level-language-based, processor-independent, multiprocessing, multiuser operating system with features comparable to Unix. It was intended to complement...
Server, Novell claimed 90% of the market for PC based servers.
While the design of NetWare 3.x and later involved a DOS partition to load NetWare server files, this feature became a liability as new users preferred the Windows graphical interface to learning DOS commands necessary to build and control a NetWare server. Novell could have eliminated this technical liability by retaining the design of NetWare 286, which installed the server file into a Novell partition and allowed the server to boot from the Novell partition without creating a bootable DOS partition. Novell finally added support for this in a Support Pack for NetWare 6.5.
As Novell used
IPX/SPXIPX/SPX stands for Internetwork Packet Exchange/Sequenced Packet Exchange. IPX and SPX are networking protocols used primarily on networks using the Novell NetWare operating systems.-Protocol Layers:...
instead of TCP/IP, they were poorly positioned to take advantage of the Internet in 1995. This resulted in Novell servers being bypassed for routing and Internet access in favor of hardware routers,
UnixUnix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...
-based operating systems such as
FreeBSDFreeBSD is a free Unix-like operating system descended from AT&T UNIX via BSD UNIX. Although for legal reasons FreeBSD cannot be called “UNIX”, as the direct descendant of BSD UNIX , FreeBSD’s internals and system APIs are UNIX-compliant...
, and
SOCKSSOCKS is an Internet protocol that routes network packets between a client and server through a proxy server. SOCKS5 additionally provides authentication so only authorized users may access a server...
and HTTP
Proxy ServersIn computer networks, a proxy server is a server that acts as an intermediary for requests from clients seeking resources from other servers. A client connects to the proxy server, requesting some service, such as a file, connection, web page, or other resource available from a different server...
on Windows and other operating systems.
NetWare 4.1x and NetWare for Small Business: Novell begins to recover
Novell priced NetWare 4.10 similarly to NetWare 3.12, allowing customers who resisted NDS (typically small businesses) to try it at no cost.
Later Novell released NetWare version 4.11 in 1996 which included many enhancements that made the operating system easier to install, easier to operate, faster, and more stable. It also included the first full 32-bit client for
Microsoft WindowsMicrosoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
-based workstations,
SMPIn computing, symmetric multiprocessing involves a multiprocessor computer hardware architecture where two or more identical processors are connected to a single shared main memory and are controlled by a single OS instance. Most common multiprocessor systems today use an SMP architecture...
support and the NetWare Administrator (NWADMIN or NWADMN32), a GUI-based administration tool for NetWare. Previous administration tools used the Cworthy interface, the character-based GUI tools such as SYSCON and PCONSOLE with blue text-based background. Some of these tools survive to this day, for instance MONITOR.NLM.
Novell packaged NetWare 4.11 with its Web server, TCP/IP support and the
NetscapeNetscape Communications is a US computer services company, best known for Netscape Navigator, its web browser. When it was an independent company, its headquarters were in Mountain View, California...
browser into a bundle dubbed
IntranetWare (also written as intraNetWare). A version designed for networks of 25 or fewer users was named
IntranetWare for Small Business and contained a limited version of NDS and tried to simplify NDS administration. The intranetWare name was dropped in NetWare 5.
During this time Novell also began to leverage its directory service, NDS, by tying their other products into the directory. Their
e-mailElectronic mail, commonly known as email or e-mail, is a method of exchanging digital messages from an author to one or more recipients. Modern email operates across the Internet or other computer networks. Some early email systems required that the author and the recipient both be online at the...
system,
GroupWiseGroupWise is a messaging and collaborative software platform from Novell that supports email, calendaring, personal information management, instant messaging, and document management. The platform consists of the client software, which is available for Windows, Mac OS X, and Linux, and the server...
, was integrated with NDS, and Novell released many other directory-enabled products such as
ZENworksNovell ZENworks, a suite of software products developed and maintained by Novell, Inc. for computer systems management, aims to manage the entire life cycle of servers, of desktop PCs , of laptops, and of handheld devices such as personal digital assistants . ZENworks recently included full disk...
and
BorderManagerBorderManager is a multi purpose network security application developed by Novell, Inc. BorderManager is designed as a proxy server, firewall, and VPN access point...
.
NetWare still required IPX/SPX as NCP used it, but Novell started to acknowledge the demand for TCP/IP with NetWare 4.11 by including tools and utilities that made it easier to create intranets and link networks to the Internet. Novell bundled tools, such as the IPX/IP gateway, to ease the connection between IPX workstations and IP networks. It also began integrating Internet technologies and support through features such as a natively hosted
web serverWeb server can refer to either the hardware or the software that helps to deliver content that can be accessed through the Internet....
.
NetWare 5.x
With the release of NetWare 5 in October 1998, Novell switched its primary NCP interface from the
IPX/SPXIPX/SPX stands for Internetwork Packet Exchange/Sequenced Packet Exchange. IPX and SPX are networking protocols used primarily on networks using the Novell NetWare operating systems.-Protocol Layers:...
network protocol to TCP/IP to meet consumer demands. IPX/SPX was still supported, but the emphasis shifted to TCP/IP. Novell also added a
GUIGui or guee is a generic term to refer to grilled dishes in Korean cuisine. These most commonly have meat or fish as their primary ingredient, but may in some cases also comprise grilled vegetables or other vegetarian ingredients. The term derives from the verb, "gupda" in Korean, which literally...
to NetWare. Other new features were:
- Novell Storage Services
Novell Storage Services is a file system used by the Novell NetWare operating system. Recently support of NSS was introduced to SUSE Linux via low-level network NCPFS protocol...
(NSS), a new file system to replace the traditional NetWare File SystemIn computing, a NetWare File System is a file system based on a heavily-modified version of FAT. It was used in the Novell NetWare operating system. It is the default and only file system for all volumes in versions 2.x through 4.x, and the default and only file system for the SYS volume...
- which was still supported
- Java virtual machine
A Java virtual machine is a virtual machine capable of executing Java bytecode. It is the code execution component of the Java software platform. Sun Microsystems stated that there are over 4.5 billion JVM-enabled devices.-Overview:...
for NetWare
- Novell Distributed Print Services (NDPS)
- ConsoleOne, a new Java-based GUI administration console
- directory-enabled Public key infrastructure
Public Key Infrastructure is a set of hardware, software, people, policies, and procedures needed to create, manage, distribute, use, store, and revoke digital certificates. In cryptography, a PKI is an arrangement that binds public keys with respective user identities by means of a certificate...
services (PKIS)
- directory-enabled DNS
The Domain Name System is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities...
and DHCPThe Dynamic Host Configuration Protocol is a network configuration protocol for hosts on Internet Protocol networks. Computers that are connected to IP networks must be configured before they can communicate with other hosts. The most essential information needed is an IP address, and a default...
servers
- support for Storage Area Network
A storage area network is a dedicated network that provides access to consolidated, block level data storage. SANs are primarily used to make storage devices, such as disk arrays, tape libraries, and optical jukeboxes, accessible to servers so that the devices appear like locally attached devices...
s (SANs)
- Novell Cluster Services (NCS)
- Oracle 8i
The Oracle Database is an object-relational database management system produced and marketed by Oracle Corporation....
with a 5-user license
The Cluster Services greatly improved on SFT-III, as NCS did not require specialized hardware or identical server configurations.
NetWare 5 was released during a time when NetWare
market shareMarket share is the percentage of a market accounted for by a specific entity. In a survey of nearly 200 senior marketing managers, 67 percent responded that they found the "dollar market share" metric very useful, while 61% found "unit market share" very useful.Marketers need to be able to...
dropped precipitously; many companies and organizations were replacing their NetWare servers with servers running
MicrosoftMicrosoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
's
Windows NTWindows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. It was a powerful high-level-language-based, processor-independent, multiprocessing, multiuser operating system with features comparable to Unix. It was intended to complement...
operating system.
Around this time, Novell also released their last upgrade to the NetWare 4 operating system, NetWare 4.2.
NetWare 5 and above supported Novell NetStorage for Internet-based access to files stored within NetWare.
Novell released NetWare 5.1 in January 2000. It introduced a number of useful tools, such as:
- IBM WebSphere Application Server
- NetWare Management Portal (later renamed Novell Remote Manager), web-based management of the operating system
- FTP
File Transfer Protocol is a standard network protocol used to transfer files from one host to another host over a TCP-based network, such as the Internet. FTP is built on a client-server architecture and utilizes separate control and data connections between the client and server...
, NNTPThe Network News Transfer Protocol is an Internet application protocol used for transporting Usenet news articles between news servers and for reading and posting articles by end user client applications...
and streaming mediaStreaming media is multimedia that is constantly received by and presented to an end-user while being delivered by a streaming provider.The term "presented" is used in this article in a general sense that includes audio or video playback. The name refers to the delivery method of the medium rather...
servers
- NetWare Web Search Server
- WebDAV
Web-based Distributed Authoring and Versioning is a set of methods based on the Hypertext Transfer Protocol that facilitates collaboration between users in editing and managing documents and files stored on World Wide Web servers...
support
NetWare 6.0
NetWare 6 was released in October 2001, shortly after its predecessor. This version has a simplified licensing scheme based on users, not servers. This allows unlimited connections per user. Novell Cluster Services was also improved to support 32-node clusters; the base NetWare 6.0 product included a two-node clustering license.
NetWare 6.5
NetWare 6.5 was released in August 2003. Some of the new features in this version included:
- more open-source products such as PHP
PHP is a general-purpose server-side scripting language originally designed for web development to produce dynamic web pages. For this purpose, PHP code is embedded into the HTML source document and interpreted by a web server with a PHP processor module, which generates the web page document...
, MySQLMySQL officially, but also commonly "My Sequel") is a relational database management system that runs as a server providing multi-user access to a number of databases. It is named after developer Michael Widenius' daughter, My...
and OpenSSHOpenSSH is a set of computer programs providing encrypted communication sessions over a computer network using the SSH protocol...
- a port of the Bash shell and a lot of traditional Unix utilities such as wget
GNU Wget is a computer program that retrieves content from web servers, and is part of the GNU Project. Its name is derived from World Wide Web and get...
, grepgrep is a command-line text-search utility originally written for Unix. The name comes from the ed command g/re/p...
, awk and sedsed is a Unix utility that parses text and implements a programming language which can apply transformations to such text. It reads input line by line , applying the operation which has been specified via the command line , and then outputs the line. It was developed from 1973 to 1974 as a Unix...
to provide additional capabilities for scripting
- iSCSI
In computing, iSCSI , is an abbreviation of Internet Small Computer System Interface, an Internet Protocol -based storage networking standard for linking data storage facilities. By carrying SCSI commands over IP networks, iSCSI is used to facilitate data transfers over intranets and to manage...
support (both target and initiator)
- Virtual Office - an "out of the box" web portal for end users providing access to e-mail, personal file storage, company address book, etc.
- Domain controller
On Windows Server Systems, a domain controller is a server that responds to security authentication requests within the Windows Server domain...
functionality
- Universal password
- DirXML Starter Pack - synchronization of user accounts with another eDirectory tree, a Windows NT domain
A Windows domain is a collection of security principals that share a central directory database. This central database contains the user accounts and security information for...
or Active Directory.
- exteNd Application Server - a Java EE 1.3-compatible application server
An application server is a software framework that provides an environment in which applications can run, no matter what the applications are or what they do...
- support for customized printer driver profiles and printer usage auditing
- NX bit
The NX bit, which stands for No eXecute, is a technology used in CPUs to segregate areas of memory for use by either storage of processor instructions or for storage of data, a feature normally only found in Harvard architecture processors...
support
- support for USB
USB is an industry standard developed in the mid-1990s that defines the cables, connectors and protocols used in a bus for connection, communication and power supply between computers and electronic devices....
storage devices
- support for encrypted volumes
The latest - and apparently last - Service Pack for NetWare 6.5 is SP8, released October 2008.
1.0
In 2003, Novell announced the successor product to NetWare: Open Enterprise Server (OES). First released in March 2005, OES completes the separation of the services traditionally associated with NetWare (such as Directory Services, and file-and-print) from the platform underlying the delivery of those services. OES is essentially a set of applications (eDirectory,
NetWare Core ProtocolThe NetWare Core Protocol is a network protocol used in some products from Novell, Inc. It is usually associated with the NetWare operating system, but parts of it have been implemented on other platforms such as Linux, Windows NT and various flavors of Unix.It is used to access file, print,...
services, iPrint, etc.) that can run atop either a
LinuxLinux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
or a NetWare kernel platform. Clustered OES implementations can even migrate services from Linux to NetWare and back again, making Novell one of the very few vendors to offer a multi-platform clustering solution.
Consequent to Novell's acquisitions of
XimianXimian was a company that provided free software desktop applications for Linux and Unix based on the GNOME platform. Ximian was founded by Miguel de Icaza and Nat Friedman in October, 1999, and was bought by Novell on August 4, 2003...
and
SuSE, a German Linux distributor, it is widely observed that Novell is moving away from NetWare and shifting its focus towards Linux. Much recent marketing seems to be focussed on getting faithful NetWare users to move to the Linux platform in future releases. The clearest indication of this direction is Novell's controversial decision to release Open Enterprise Server in Linux form only. Novell later watered down this decision and stated that NetWare's 90 million users would be supported until at least 2015. Meanwhile, many former NetWare customers rejected Novell's Linux efforts for other distributions like
Red HatRed Hat, Inc. is an S&P 500 company in the free and open source software sector, and a major Linux distribution vendor. Founded in 1993, Red Hat has its corporate headquarters in Raleigh, North Carolina with satellite offices worldwide....
. Some of Novell's NetWare supporters have taken it upon themselves to petition Novell to keep NetWare in development.
2.0
OES 2 was released on October 8, 2007. It includes NetWare 6.5 SP7, which supports running as a paravirtualized guest inside the
XenXen is a virtual-machine monitor providing services that allow multiple computer operating systems to execute on the same computer hardware concurrently....
hypervisor and new Linux based version using SLES10.
New features include:
- 64bit support
- Virtualization
- Dynamic Storage Technology, which provide Shadow Volumes
- Domain services for Windows (provided in OES 2 service pack 1)
Current NetWare situation
some organizations still use Novell NetWare, but its ongoing decline in popularity began in the mid-1990s, when NetWare was the
de factoDe facto is a Latin expression that means "concerning fact." In law, it often means "in practice but not necessarily ordained by law" or "in practice or actuality, but not officially established." It is commonly used in contrast to de jure when referring to matters of law, governance, or...
standard for file and print software for the Intel x86 server platform. Modern (2009) NetWare and OES installations are used by larger organizations that may need the added flexibility they provide.
Microsoft successfully shifted market share away from NetWare products toward their own in the late-1990s. Microsoft's more aggressive marketing was aimed directly to management through major magazines; Novell NetWare's was through IT specialist magazines with distribution limited to select IT personnel.
Novell did not adapt their pricing structure accordingly and NetWare sales suffered at the hands of those corporate decision makers whose valuation was based on initial licensing fees. As a result, organizations that still use NetWare, eDirectory, and Novell software often have a hybrid infrastructure of NetWare, Linux, and Windows servers.
NetWare ELS / NetWare Lite / Personal NetWare
Novell introduced NetWare ELS (for Entry Level System) in 1987. In 1991 Novell introduced a radically different and cheaper product, NetWare Lite 1.0 (NWL), in answer to Artisoft's similar
LANtasticLANtastic is a peer-to-peer local area network operating system for DOS, Microsoft Windows, Novell NetWare and OS/2. LANtastic supports Ethernet, ARCNET and Token Ring adapters as well as its original twisted-pair adapter at ....
. Both were peer-to-peer systems, where no specialist server was required, but instead all PCs on the network could share their resources.
The product was upgraded to NetWare Lite 1.1 and also came bundled with some issues of DR DOS 6.0. Some components of NetWare Lite were used in Novell's NetWare PalmDOS 1 in 1992.
Significantly reworked, the product line became Personal NetWare 1.0 (PNW) in 1993. The
ODIThe Open Data-Link Interface , developed by Apple and Novell, serves the same function as Microsoft and 3COM's Network Driver Interface Specification . Originally, ODI was written for NetWare and Macintosh environments. Like NDIS, ODI provides rules that establish a vendor-neutral interface between...
/VLM (for
Open Datalink InterfaceThe Open Data-Link Interface , developed by Apple and Novell, serves the same function as Microsoft and 3COM's Network Driver Interface Specification . Originally, ODI was written for NetWare and Macintosh environments. Like NDIS, ODI provides rules that establish a vendor-neutral interface between...
) 16-bit
DOSDOS, short for "Disk Operating System", is an acronym for several closely related operating systems that dominated the IBM PC compatible market between 1981 and 1995, or until about 2000 if one includes the partially DOS-based Microsoft Windows versions 95, 98, and Millennium Edition.Related...
client portion of the drivers now supported individually loadable VLMs for an improved flexibility and customizability, whereas the server portion could utilize Novell's
DPMSDOS Protected Mode Services is a set of extended DOS memory management services to allow DPMS-enabled DOS drivers to load and execute in extended memory and protected mode....
(
DOS Protected Mode ServicesDOS Protected Mode Services is a set of extended DOS memory management services to allow DPMS-enabled DOS drivers to load and execute in extended memory and protected mode....
), if loaded, to reduce its
conventional memoryIn DOS memory management, conventional memory, also called base memory, is the first 640 kilobytes of the memory on IBM PC or compatible systems. It is the read-write memory usable by the operating system and application programs...
footprint and run in
extended memoryIn DOS memory management, extended memory refers to memory above the first megabyte of address space in an IBM PC or compatible with an 80286 or later processor. The term is mainly used under the DOS and Windows operating systems...
and
protected modeIn computing, protected mode, also called protected virtual address mode, is an operational mode of x86-compatible central processing units...
. The NetWare Lite disk cache NLCACHE had been reworked into NWCACHE, which was easier to set up and could utilize DPMS as well, thereby reducing the DOS memory footprint and significantly speeding up disk performance. Personal NetWare came bundled with the network-enabled game
NetWarsNetWars was an IPX-based 3D vector-graphics computer game released by Novell in 1993 for DOS to demonstrate NetWare capabilities. It was written by Edward Hill, one of Novell's engineers in its European Development Centre in Hungerford, UK...
2.06.
The Personal NetWare 1.0 product saw five maintenance upgrades as well as various comprehensive updates to the corresponding VLM client driver suite (1.0, 1.1, 1.20, 1.21) as part of the Novell Client Kit for DOS & Windows up to November 1996, which added many new MLID (Media Link Interface Driver) drivers, including drivers for
SLIPThe Serial Line Internet Protocol is an encapsulation of the Internet Protocol designed to work over serial ports and modem connections. It is documented in RFC 1055...
and
PPPIn networking, the Point-to-Point Protocol is a data link protocol commonly used in establishing a direct connection between two networking nodes...
, as well as extra codepages and languages.
A full version of Personal NetWare (save the interactive tutorials) also came bundled with Novell DOS 7 in 1993/1994 at a price similar to that of the stand-alone version of Personal NetWare. Portions of Personal NetWare were incorporated into Novell's NetWare Mobile for DOS and LAN Workplace for DOS products, and as such compatible TCP/IP drivers became available for the system as well. Later, Personal NetWare was bundled with full versions of
CalderaCaldera was a US-based software company founded in 1994 to develop Linux- and DOS-based operating system products.- Caldera :Caldera, Inc...
OpenDOS 7.01,
DR-DOSDR-DOS is an MS-DOS-compatible operating system for IBM PC-compatible personal computers, originally developed by Gary Kildall's Digital Research and derived from Concurrent PC DOS 6.0, which was an advanced successor of CP/M-86...
7.02 and 7.03 between 1997 and 1999, however, these bundles were delivered with the same Personal NetWare files shipping with Novell DOS 7, not the upgraded files, which had been made available for download by Novell since 1994. The ODI/VLM client stack with TCP/IP drivers also found its way into the DR-WebSpyder distribution.
When Novell in 1996 introduced its ODI32/NIOS 32-bit DOS/Windows client (Client32), it used NLM instead of VLM modules. While the NIOS client could reduce the conventional memory footprint downto 2 to 5 KB in total, the lack of something like a "PNW.NLM" module (in analogy to the VLM client's PNW.VLM) made it impossible to use the new client in conjunction with a Personal NetWare server.
Performance
NetWare dominated the network operating system (NOS) market from the mid-1980s through the mid- to late-1990s due to its extremely high performance relative to other NOS technologies. Most benchmarks during this period demonstrated a 5:1 to 10:1 performance advantage over products from Microsoft, Banyan, and others. One noteworthy benchmark pitted NetWare 3.x running NFS services over TCP/IP (not NetWare's native IPX protocol) against a dedicated Auspex NFS server and a SCO Unix server running NFS service. NetWare NFS outperformed both 'native' NFS systems and claimed a 2:1 performance advantage over SCO Unix NFS on the same hardware.
The reasons for NetWare's performance advantage are given below.
File service instead of disk service
When first developed, nearly all LAN storage was based on the disk server model. This meant that if a client computer wanted to read a particular block from a particular file it would have to issue the following requests across the relatively slow LAN:
- Read first block of directory
- Continue reading subsequent directory blocks until the directory block containing the information on the desired file was found, could be many directory blocks
- Read through multiple file entry blocks until the block containing the location of the desired file block was found, could be many directory blocks
- Read the desired data block
NetWare, since it was based on a file service model, interacted with the client at the file API level:
- Send file open request (if this hadn't already been done)
- Send a request for the desired data from the file
All of the work of searching the directory to figure out where the desired data was physically located on the disk was performed at high speed locally on the server.
By the mid-1980s, most NOS products had shifted from the disk service to the file service model. Today, the disk service model is making a comeback, see
SANA storage area network is a dedicated network that provides access to consolidated, block level data storage. SANs are primarily used to make storage devices, such as disk arrays, tape libraries, and optical jukeboxes, accessible to servers so that the devices appear like locally attached devices...
.
Aggressive caching
From the start, the NetWare design focused on servers with copious amounts of RAM. The entire file allocation table (FAT) was read into RAM when a volume was mounted, thereby requiring a minimum amount of RAM proportional to online disk space; adding a disk to a server would often require a RAM upgrade as well. Unlike most competing
network operating systemA networking operating system , also referred to as the Dialoguer, is the software that runs on a server and enables the server to manage data, users, groups, security, applications, and other networking functions...
s prior to Windows NT, NetWare automatically used all otherwise unused RAM for caching active files, employing delayed write-backs to facilitate re-ordering of disk requests (
elevator seeksThe elevator algorithm is a disk scheduling algorithm to determine the motion of the disk's arm and head in servicing read and write requests....
). An unexpected shutdown could therefore corrupt data, making an
uninterruptible power supplyAn uninterruptible power supply, also uninterruptible power source, UPS or battery/flywheel backup, is an electrical apparatus that provides emergency power to a load when the input power source, typically mains power, fails...
practically a mandatory part of a server installation.
The default dirty cache delay time was fixed at 2.2 seconds in NetWare 286 versions 2.x. Starting with NetWare 386 3.x, the dirty disk cache delay time and dirty directory cache delay time settings controlled the amount of time the server would cache changed ("dirty") data before saving (flushing) the data to a hard drive. The default setting of 3.3 seconds could be decreased to 0.5 seconds but not reduced to zero, while the maximum delay was 10 seconds. The option to increase the cache delay to 10 seconds provided a significant performance boost. Windows 2000 and 2003 server do not allow adjustment to the cache delay time. Instead, they use an algorithm that adjusts cache delay.
Efficiency of NetWare Core Protocol (NCP)
Most network protocols in use at the time NetWare was developed didn't trust the network to deliver messages. A typical client file read would work something like this:
- Client sends read request to server
- Server acknowledges request
- Client acknowledges acknowledgement
- Server sends requested data to client
- Client acknowledges data
- Server acknowledges acknowledgement
In contrast, NCP was based on the idea that networks worked perfectly most of the time, so the reply to a request served as the acknowledgement. Here is an example of a client read request using this model:
- Client sends read request to server
- Server sends requested data to client
All requests contained a sequence number, so if the client didn't receive a response within an appropriate amount of time it would re-send the request with the same sequence number. If the server had already processed the request it would resend the cached response, if it had not yet had time to process the request it would only send a "positive acknowledgement". The bottom line to this 'trust the network' approach was a 2/3 reduction in network transactions and the associated latency.
Non-preemptive OS designed for network services
One of the raging debates of the 90s was whether it was more appropriate for network file service to be performed by a software layer running on top of a general purpose operating system, or by a special purpose operating system. NetWare was a special purpose operating system, not a timesharing OS. It was written from the ground up as a platform for client-server processing services. Initially it focused on file and print services, but later demonstrated its flexibility by running database, email, web and other services as well. It also performed efficiently as a router, supporting IPX, TCP/IP, and Appletalk, though it never offered the flexibility of a 'hardware' router.
In 4.x and earlier versions, NetWare did not support
preemptionIn computing, preemption is the act of temporarily interrupting a task being carried out by a computer system, without requiring its cooperation, and with the intention of resuming the task at a later time. Such a change is known as a context switch...
,
virtual memoryIn computing, virtual memory is a memory management technique developed for multitasking kernels. This technique virtualizes a computer architecture's various forms of computer data storage , allowing a program to be designed as though there is only one kind of memory, "virtual" memory, which...
,
graphical user interfacesGui or guee is a generic term to refer to grilled dishes in Korean cuisine. These most commonly have meat or fish as their primary ingredient, but may in some cases also comprise grilled vegetables or other vegetarian ingredients. The term derives from the verb, "gupda" in Korean, which literally...
, etc. Processes and services running under the NetWare OS were expected to be cooperative, that is to process a request and return control to the OS in a timely fashion. On the down side, this trust of application processes to manage themselves could lead to a misbehaving application bringing down the server.
By comparison, general-purpose operating systems such as
UnixUnix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...
or
Microsoft WindowsMicrosoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
were based on an interactive, time-sharing model where competing programs would consume all available resources if not held in check by the operating system. Such environments operated by preemption, memory virtualization, etc., generating significant overhead because there were never enough resources to do everything every application desired. These systems improved over time as network services shed their “application” stigma and moved deeper into the kernel of the “general purpose” OS, but they never equaled the efficiency of NetWare.
Probably the single greatest reason for Novell's success during the '80s and '90s was the efficiency of NetWare compared to general purpose operating systems. However, as microprocessors increased in power, efficiency became less and less of an issue. With the introduction of the Pentium processor, NetWare's performance advantage began to be outweighed by the complexity of managing and developing applications for the NetWare environment.
External links