Technology Reference Guide

	Technology Reference Guide 4. Network Operating Systems D. IBM OS/2 LAN Server

What is it?
OS/2 LAN Server is a product offered by IBM, that provides shared file, serial device and print services. It is a descendant of LAN Manager, which was co-developed by IBM and Microsoft. LAN Server runs as a process on IBMs OS/2 operating system. OS/2 is a multi-tasking 32-bit operating system, that can run this server process, while handling other programs at the same time. Strictly speaking, LAN Server is not a network operating system, but rather an application running on a stand-alone operating system that provides network services.

What does it do?
LAN Server user management is based on the concept of domains. A domain is a logical group of users and servers, managed by a server designated as the domain controller. It is possible to designate an additional server as a backup domain controller, as well as including other servers in a single domain. The domain controller contains files that designate the available network resources, called the domain control database (DCDB), as well as user and group definition files. These files can be duplicated, or replicated, on backup domain controllers.

The client workstations access the LAN by means of requester software. Because of the design of LAN Server and its relationship to the OS/2 operating system, servers can simultaneously act as clients, and vice-versa. Users can log into only one domain at a time, but may have access to multiple domains through multiple logins, if they have an appropriate user access control profile in each domain. LAN Server provides the ability to give resources short nicknames called aliases. It also provides the ability to create groups of users, to simplify granting access rights.

LAN Server provides access to file services, which are protected by access rights. It provides shared print services through the use of network print queues and associated printer pools. Lastly LAN Server provides the ability to share serial devices, such as serial printers or modems.

LAN Server runs on top of NetBIOS transport/network protocols, and provides an open multi-protocol adapter interface using NDIS (network device interface specification). LAN Server also provides support for TCP/IP . See the Protocols section of this guide for more information.

How is it used?
OS/2 LAN Server is used to provide file and print services on PC LANs, often in IBM computing environments. It supports DOS, OS/2 and Macintosh clients. It offers an advantage in LAN environments needing application servers, since the multi-tasking features of OS/2 can provide application services and file services at the same time. A protocol called Named Pipes sets up and maintains virtual channels that allow clients to access application services. The domain concept makes LAN Server somewhat limited in its application to large-scale enterprise-wide networks.

Where do I get more information?
Contact your local CBV Office.