About The NetWare Operating System
----------------------------------
NetWare is the foundation of Novell's product line. It was introduced
in 1983, and is now in its seventh generation of development. NetWare
offers tremendous connectivity, expandability, and communications
capabilities.
NetWare Operating System Software supports 45 popular LAN hardware
configurations.
Compatibility
-------------
NetWare is compatible with virtually all PC networking software and
hardware.
NETWORK HARDWARE
NetWare supports every major network topology and every major
manufacturer's hardware (including IBM's PC and Token-Ring networks, AT&T
StarLAN, ARCNET, and many Ethernet-type networks). NetWare preserves
current hardware investments and lets clients choose the hardware that best
suits their price/performance needs. Best of all, the NetWare user
interface remains the same regardless of the hardware it is running on.
COEXISTENCE WITH NON-NETWARE PRODUCTS
NetWare can coexist with many non-NetWare products, such as packages
developed by IBM for PC-to-mainframe communications. Since both NetWare
and non-NetWare products can run on the same network simultaneously,
clients are not limited to using only NetWare on a NetWare network. For
example, using the TCP/IP Gateway Option, a file server can use both
NetWare and TCP environments simultaneously. NetWare also supports
important new products being developed by IBM (APPC/LU 6.2 protocols) and
other vendors.
CONNECTIVITY
NetWare lets clients interconnect networks through either gateways or
bridges. Bridged networks communicate and share information in a way that
is transparent to the user. This lets clients purchase networks or add
networks, as necessary, without making the original hardware obsolete.
Connectivity protects investments in training, software, and hardware.
EXPANDABILITY
NetWare networks can grow easily when the single network limit is reached,
clients can simply bridge the network to another network and continue
adding workstations and file servers.
It is easy to increase the disk storage and memory capacity of a NetWare
network. Disk subsystems may be added to increase hard disk storage
capacity to as much as to 2GB. Currently, we have found that a partition
size at least 1MB smaller than 2GB seems to work acceptably. Larger volume
sizes might cause negative file sizes, inability to copy files because
"More space is needed" even though plenty of space is available. You might
encounter these symptoms when Novell servers publish volumes larger than
2GB over the network.
Because NetWare can run in protected mode on 286-type file servers, NetWare
supports up to 8MB of Random Access Memory (RAM). Additional RAM improves
hard disk performance.
DISTRIBUTED PROCESSING
Under NetWare, each workstation is an independent computer performing its
own processing. The file server manages the shared resources and
coordinates network activity but does not actually process data. This
method of managing data is called "distributed processing".
Because each workstation has its own processing power, adding PCs to the
network does not decrease the file server's performance. In contrast,
terminals connected to mini and mainframe systems share the processing
power, which decreases the power available to each user.
OPERATING SYSTEM TECHNIQUES
Reading from and writing to the file server hard disk occurs more
frequently than any other network task. NetWare is specifically designed to
perform fast file reads and writes. Other performance enhancements include:
SINGLE-TASKING VERSUS MULTITASKING
NetWare is a multitasking operating system. Performance degradation in the
single-tasking environment is magnified with every workstation on the
network. Unlike single-tasking operating systems such as DOS, NetWare can
service many workstation requests and many hard disks simultaneously.
DIRECTORY HASHING
NetWare minimizes file searching time by efficiently organizing
information. Specifically, NetWare indexes directory entries so it can
quickly find a file (similar to the way that dictionary entries are
alphabetized to enable the user to locate the entry at once).
DIRECTORY CACHING
NetWare saves time by putting a copy of each directory in the file server's
RAM. RAM access is much faster than hard disk access, so directory caching
significantly increases network performance. Since the disk is accessed
less frequently, directory caching also helps eliminate disk-related
bottlenecks.
FILE CACHING
NetWare continually tracks parts of files used most often and stores them
in RAM. NetWare increases performance by anticipating subsequent requests
and reading large blocks of information into RAM. This increases
performance by saving "seeks" to the disk, which reduces access time and
helps eliminate bottlenecks.
ELEVATOR SEEKING
The disk read-write head travels across the disk and picks up files in its
direction of travel, much like an elevator taking floor requests. When a
head reaches the end of the disk, it goes in the other direction, picking
up new requests. This significantly decreases disk wear and tear and
increases disk throughput by up to 50%.
Security
--------
A network supervisor controls network security, which may be implemented on
the file server, directory, and file levels. Access to network resources is
based on user profiles that the supervisor assigns. Individuals can also
protect their personal data without the assistance of a network supervisor.
Value-Added Processes
---------------------
NetWare offers an elegant solution for developers who would like to place
value-added servers and services on the internet. A common File Service
Interface provides for the implementation of value-added processes (VAP) in
NetWare servers and bridges. Value-added processes bring new services to
Advanced NetWare--namely, specialized servers, the incorporation of
third-party devices and specialized technologies. Examples of VAPs are
data base servers, communications servers, and print servers.
MHS
---
Message Handling Service (MHS) is a value-added service that provides
message transfer and routing services for LAN-based applications. NetWare
MHS moves messages between PC LAN, minicomputer, and mainframe environments
throughout a dispersed wide-area network. In the future, MHS will support
protocols such as X.25, HDLC, SNA, SDLC, and more.
Continued in "Macintosh-To-Novell Netware With AppleTalk, Part 3 of 3."