The Best of Worlds

ENT,  Sept 10, 1998  by Mark McFadden

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The entry of Windows NT systems into Unix shops means that the two OSs will have to co-exist for years to come. How can IS managers share NT and Unix resources to achieve an optimal mixed- platform enterprise?

Can't we all just get along? International Data Corp. (IDC, Framingham, Mass., www.idc.com) has reported that only two server operating environments have seen growth in deployment in the past year: Windows NT and Unix. IDC's survey of large, corporate users showed that growth in new Unix implementations remained steady: at about 16 percent per year for the major dialects of Unix. The number of Windows NT licenses shot up at about 80 percent, according to the survey, nearly eight times the overall growth rate for all server operating environments combined. Windows NT's superior price and performance seem to be the biggest factors for the operating system's success, yet the figures also show that both Unix and Windows NT systems are going to be around for some time.

For many enterprises, this will mean continuing to cope with a mixed environment of Unix and Windows NT platforms. "There isn't a single large customer who isn't looking at the issue of integration," says Mark Ditto of WRQ (Seattle, www.wrq.com). As technical product manager for WRQ's Reflection series of X servers and TCP/IP products, Ditto says that "integrating Unix and Windows NT means three things: sharing files across platform boundaries, using any printer or other peripheral attached in either environment, and allowing applications to be built to run in either environment."

Underlying the success of integration is a common networking technology. Once associated almost exclusively with the Unix environment, TCP/IP now provides the common foundation on which shared services are built. As support for TCP/IP improved under Windows NT, it became possible for IS to provide reliable access to shared peripherals and even build shared file services. Because TCP/IP is based on vendor- neutral, internationally accepted standards, vendors can independently build software solutions that knit Unix and Windows NT systems together.

In traditional Microsoft networks, resource sharing is accomplished using a protocol called Server Message Blocks (SMB). In a network of computers using Microsoft operating systems, SMB is used to move packets of data over networks using protocols such as NetBEUI, TCP/IP or IPX. To exchange resources with computers that are not running Microsoft protocols, either the Windows NT machines must be enabled to understand another data exchange protocol, or the non-Microsoft computer needs to be made to understand SMB.

This pair of approaches -- adapting the Windows NT environment to understand non-native protocols and adapting other environments so that they understand SMB -- illustrates the two fundamental strategies for providing Unix-Windows NT integration.

Shared Printer Support

Rather than duplicate printers, plotters and other graphic output devices in a combined Unix-Windows NT environment, administrators of mixed environments often enable systems to share expensive peripherals. Fortunately, shared printer support is reasonably easy to arrange for mixed networks.

Printer sharing in the Unix environment uses a client/server strategy that separates printer job submission from printer queue control. LPR is the client printing component for Unix systems, and LPD is the printer control, queuing and server process. The LPR/LPD printing protocol is so common that Windows NT provides support for it as part of its TCP/IP services.

However, Windows NT does not install TCP/IP printing by default. Instead, users must add it using the Network applet in the Control Panel. Once an administrator has installed TCP/IP printing, he or she must start Windows NT's LPDSVC service to enable connections between the Windows printer drivers and Unix-based printers. Once these minor administrative tasks are complete, printing to Unix-based printers is as simple as setting up any new printer and associating it with an LPR port.

While LPR/LPD printers are extremely easy to set up, they suffer from one major drawback in the Windows NT environment: They do not appear as shared resources in the Network Neighborhood. One approach to making shared Unix-based printers available under browsers such as Explorer and Network Neighborhood is to use the printing services that come with the Network File System (NFS). Windows NT workstations are able to browse the NFS network and connect to Unix-attached printers. If your network uses NFS for other services, it can also use NFS to eliminate the overhead of adding LPR printers to every workstation. As users change from one Unix printer to another, NFS-based printing makes the change easier.

Share and Share Alike

While NFS works well to share Unix-based printers, its primary purpose is to share files over a network. Windows NT-savvy administrators will find that adding NFS is a relatively simple task. NFS servers "export" or share a file system. The shared file system can then be mapped by the client as a network drive. Windows-based clients find available shares by browsing for network services. If a system administrator wants to make the NFS share appear as a native part of the Windows network, he or she can use an NFS gateway to map traditional Windows SMB requests to the NFS shared service.