MSM-NET and MSM-LAT

MSM-NET is an add-on package that provides networking capabilities for MSM-Server for Windows NT, MSM-Server for DOS and MSM-Server for UNIX systems. It offers high-performance, distributed databases on local area networks. When networking between MSM systems, caching algorithms allow routines and globals to be shared at the physical block level. Because the disk buffer cache is shared between systems, performance is very close to what can be obtained from running all users on a single system. Native DDP access to DSM and ISM systems, as well as OMI connects to other M vendors, are also supported. MSM-LAT is our implementation of Digital Equipment Corporation's (DEC) Local Area Transport (LAT) protocol. This package functions as an interface between a wide variety of LAT-compatible terminal servers and the MSM-Server for Windows NT, MSM-Server for DOS and MSM-Server for UNIX environments. Layered on top of the MSM-NET package, it allows large terminal networks to be created that have access to multiple machines. It also provides load balancing between systems and simplifies management of printers and modems.

Client/Server Computing
Client/server computing provides a flexible method of distributing processing among multiple machines. Typically, a configuration consists of one or more file servers. The file servers contain all of the data and programs required by the clients. One or more clients are attached to the servers through a local area network.

MSM-NET uses a building block approach to create large, multi-user configurations that support many hundreds of users. By creating configurations that consist of file servers and compute servers, capacity can be increased by adding additional servers. For example, if additional users are given access to the system because a new application has been installed, an additional compute server can be added to provide increased computing power. Similarly, print servers can be added to the configuration to off-load background activity. All of this can be done in a manner that is transparent to the users and the application code. MSM-NET also provides the mechanism for creating true client/server computing environments. Client/server configurations can be implemented that use PCs as clients and as servers. Configurations can also be used that combine PC, UNIX, or Windows NT systems, with any of these system types acting as clients, as servers or as both client and server.

Remote Volume Groups
Higher performance client/server computing in MSM-NET is achieved through remote volume groups (RVGs). This feature allows the disk buffer cache on a server node to be distributed to and shared by client nodes connected to the server. When a client node requires routines or global data, the entire disk block is transferred to the client. Subsequent accesses to data stored in the same physical block can be satisfied from the client’s cache without the need for network communication with the server. Through MSM-NET, MSM ensures proper buffer backup and synchronization.

MSM-NET’s RVG feature allows client/server systems to be any combination of MSM-Server for Windows NT, MSM-Server for DOS and MSM-Server for UNIX. Routines and globals can be shared across the different hardware platforms and across the different operating systems. All of the necessary adjustments to the routines and globals to accommodate hardware differences are performed in a manner that is transparent to the users. With RVGs, users can logon to remotely mounted volume groups; load, edit, and save routines; access globals; and perform other operations just as if they were logged onto a local volume group. Also, the JOB command can be used to initiate a job on any server attached to the network.

DDP Protocol
In addition to the RVG protocol between MSM systems, MSM-NET supports the Distributed Data Processing protocol to communicate with DSM and ISM systems. This protocol is used to share global data between systems. MSM-NET also supports the automatic network configuration features found in DSM. Because ISM systems do not support automatic configuration, each ISM node in the network must be explicitly defined to the system.

OMI Protocol
The Open M Interconnect (OMI) Type A extension to the M standard is fully supported by MSM-NET. Using the TCP/IP interface, MSM can exchange data with other M systems. Because OMI was developed as a general purpose interconnect with modest performance objectives, it should be used in low-volume applications where occasional access to remote data is required.

Supported Interfaces
MSM-NET can be layered on top of other protocols (such as TCP/IP, NETBIOS, and IPX/SPX) or interfaced directly to the Data Link Layer (DLL) using packet driver, token ring DLC, NDIS, ODI, and native WD/SMC support. Ethernet DLL access is required to support LAT, DEC DDP, and ISM DDP. MSM-NETDDP and RVG are supported using all interfaces.

Global Translation and Replication
Global translation provides a mechanism through which every reference to a particular global in a user class identifier (UCI) is internally changed to reference a global with the same name in a different UCI. The UCI may be in the same volume group, a different volume group on the same system, or a different volume group on a remote system. The replication feature allows global SETs and KILLs to be duplicated in up to seven additional UCIs. Like translation, the UCIs may be in different volume groups on the same machine or on different machines. Note that a global can be translated and replicated at the same time.

Network Security
Network security is provided at two levels. First, passwords can be maintained for network nodes and verified with connecting nodes (i.e., establishing circuits). This level of security works with MSM systems and with DSM systems. Second, protection can be maintained on a global-by-global basis. Systems, groups, users, or the entire world can be granted read, write, delete, or no access rights to each global on the system.

LAT Protocol
MSM-LAT is an implementation of the Local Area Transport (LAT) protocol developed by the Digital Equipment Corporation (DEC). We have licensed the protocol from DEC and made it available for MSM-Server for Windows NT, MSM-Server for DOS and MSM-Server for UNIX systems. Features of MSM-LAT include:

• Terminal Servers: MSM-LAT supports all of the popular LAT compatible terminal servers, including DEC, Datability, Xyplex and Equinox.
• Load Balancing: When terminal servers are connected to multiple MSM systems, automatic load balancing is performed. When the users select a service, they are connected to the least heavily loaded system offering the service.
• Printer and Modem Control: Using MSM-LAT, printers, modems, and other types of devices can be shared among multiple systems. The host-initiated connect feature of LAT is used to dynamically attach a device to a machine.
• Dynamic Reconfiguration of Services: Used in conjunction with the cross-system journaling feature, the failed service can be routed to a “hot standby” machine in the event of a system failure.
• Low Overhead: The LAT protocol provides superior terminal performance with extremely low overhead compared to other terminal connect protocols, such as Telnet under UNIX.
• Direct MSM Logons: As a by-product of MSM's direct LAT support under UNIX, users bypass the UNIX logon prompt and are logged directly into MSM. This allows the user to purchase a minimum-user UNIX license (enough to “administer” the system), resulting in a major potential savings for large installations.

Summary of Features

Remote Volume Groups
Remote volume groups allow routines and globals to be shared between any combination of MSM-Server for Windows NT, MSM-Server for DOS and MSM-Server for UNIX.

DDP to DSM and Other Systems
MSM-NET supports the Distributed Data Processing (DDP) protocol to DSM and ISM systems, as well as the Open M Interconnect (OMI) protocol.

LAN Compatible
These products operate concurrently with network operating systems such as Banyan Vines, Microsoft LAN Manager, and Novell Netware.

Multiple Adapters and Protocols
MSM-NET and MSM-LAT support token ring and Ethernet adapters, TCP/IP, IPX/SPX, and packet drivers.

Client/Server Configurations
MSM-Server for Windows NT, MSM-Server for DOS and MSM-Server for UNIX can be used as clients or as servers, and any combination of products can be used in client/server configurations.

LAT Support
MSM-LAT provides the ability to use multiple terminal servers, load balancing, and host-initiated connects for printer and modem control. MSM-LAT operates with any of the Ethernet boards supported by MSM-NET.

Network Management
MSM-NET allows automatic network configuration as nodes are started and stopped. This product also includes a comprehensive set of utilities to configure and manage the network.

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