MSM-Server for DOS

MSM-Server for DOS (formerly known as MSM-PC/PLUS) is a full implementation of MSM for Intel 80386, 80486, and Pentium. It includes a wide variety of development tools and a comprehensive library of utility programs for configuring and managing the system. The architecture of MSM-Server for DOS allows it to be used in configurations ranging from single-user workstation applications to large, multi-user minicomputer replacement systems that support hundreds of concurrent users.

MSM-Server for DOS also provides a range of options for connecting terminals to the system. It supports the built-in serial ports and most popular serial port boards available for PCs, including Arnet, AST, and Digiboard. With Arnet Smartport boards, MSM-Server for DOS can support up to 128 direct connects. For increased connectivity and flexibility, the optional MSM-LAT package can be used to support LAT terminal servers connected through Ethernet. With MSM-LAT, up to 1,024 devices (terminals, printers, and modems) can be accessed by a single MSM-Server for DOS system.

Protected Mode
MSM-Server for DOS takes advantage of the significant capabilities that have been built into the Intel 80386, 80486, and Pentium microprocessors. Using a 32-bit DOS extender, MSM-Server for DOS runs in extended memory apart from the standard memory. Using this approach, almost all of the memory in the 640 KB region needed to run applications is left free for use by DOS. This memory can then be used by large TSR programs, external callable routines developed by the user, or for DOS applications called directly from MSM.

By running with a 32-bit DOS extender, MSM-Server for DOS has the ability to directly address up to 64 megs of memory that is divided between user partitions and the disk buffer cache. Each partition can be up to 256 KB in size, and can support up to 384 partitions (256 users and 128 background jobs). The size of the disk buffer cache, which is used to store routine and global disk blocks, is only limited by the amount of real memory installed on the system (up to the 64 megabyte limit).

Device Connection
Up to 1,024 devices can be attached to MSM-Server for DOS using any combination of built-in serial ports and Arnet, AST, Digiboard, and Quadport serial port boards. Terminal servers that support the LAT protocol can be connected to MSM-Server for DOS through Ethernet.

Optimized Disk I/O
Access to the underlying DOS file system has been optimized. Some of these features include interrupt disk I/O and buffer caching. The user or administrator can also configure the system to bypass the DOS File Allocation Table.

Large Databases
Within MSM-Server for DOS, data is stored in volume groups. Each volume group can include from one to eight volumes, with each volume being a separate DOS file. Each volume group supports up to 30 user class identifiers that can be used to separate applications and data. Volume groups can be up to 16 GB in size; a single system can support up to 32 volume groups, for a total database size of 512 GB. Utilities to maintain, compress, validate, and repair databases are also provided.

Networking
MSM-NET, an optional add-on package, adds extensive networking capabilities to the MSM-Server for DOS product. The remote volume group (RVG) feature allows volume groups (routines and globals) to be shared among processors. DDP access to Caché, DSM, and ISM is supported, as well as OMI access to other vendors. Support for protocols such as IPX/SPX, NETBIOS, and TCP/IP is included. Global translation, replication, and security are also provided.

Product Restrictions (MSM Server for DOS only)
MSM Server for DOS was designed to run on legacy systems running MS-DOS version 6.22 (although it should run on earlier versions of DOS). It will not operate properly on Windows based operating systems. Please refer to MSM for Windows-NT or MSM for Windows-95 products, for further information on MSM products that run on the Windows-NT, Windows-98, and Windows-95 operating systems.

MSM-PC/PLUS also is incapable of referencing Plug'n'Play devices, and may not run properly on systems so equipped. It will also not run on "legacy-free" hardware. MSM-PC/PLUS has not been tested on hardware newer than a Pentium-90 system, and may not operate properly on faster hardware. This limitation is entirely based on the hardware configuration and BIOS. InterSystems does not maintain a list of known working hardware.

Editors and Debuggers
Included with the system is a CUA-compliant, full-screen editor that operates on the console or terminals attached to the system. Also included is an interactive program debugger that supports breakpoints, command stepping, and line stepping.

Integration with DOS
Because MSM-Server for DOS operates in protected mode, up to 570 K of DOS's 640 KB region can be left free for TSRs and callable programs. This allows the DOS shell to be invoked from MSM and most other DOS programs. When DOS programs are called, MSM-Server for DOS operations are suspended because DOS is a single-user, single-tasking operating system.

Console Support
The console device emulates VT420 escape sequences; fully supports mouse devices, including asynchronous events; provides built-in windowing capabilities; and produces 132-column output.

Windows on Dumb Terminals
Through use of a mnemonic name space, MSM-Server for DOS provides windowing for dumb terminals. Windows can be opened, moved, or resized. Information on the screen that is overlaid by the windows is automatically refreshed by MSM-Server for DOS. This feature is available on most terminal types.

External Interfaces
MSM-Server for DOS supports Dynamic Data Exchange (DDE) with Windows applications. The optional MSM-Activate package allows other applications to access the MSM database, and the optional MSM-XCALL package is a full development kit for writing externally callable routines written in other programming languages.

Performance Monitoring
The RTHIST utility provides a tool for analyzing system performance. It includes command execution by routine; global accesses by routine; global accesses by name; system statistics; computed ratios; terminal response time statistics; and disk and CPU utilization.

Standards Compliance
MSM-Server for DOS conforms to the ISO ANSI and FIPS standards and includes most Type A extensions approved by the M Development Committee (MDC).

Source-Code Compatible
Because all implementations of MSM are source-code compatible, code developed on one platform can be moved to any other MSM system without change.

Protected Mode
For Intel 386 or newer microprocessors, MSM-Server for DOS runs using the DOS Protected Mode Interface (DPMI) to fully utilize 32-bit features.

Multi-User Support
MSM-Server for DOS takes advantage of expanded memory to support hundreds of concurrent users. Serial port I/O cards can be used to attach additional terminal devices.

PC Compatible
MSM-Server for DOS is compatible with most DOS environments, TSR programs, and Microsoft Windows. It allows DOS programs to be called from MSM and includes Windows, Novell, and DESQview awareness.

Compiled/Optimized Code
MSM-Server for DOS produces efficient p-code for increased performance at run time. Programs can be distributed in p-code-only format for security.

Resilient Architecture
Features like before-image and after-image journaling, online backup, and cross-system journaling enhance high-availability system configurations.

Networking Capabilities
Cache sharing algorithms allow routines and globals to be shared between all MSM systems. MSM-Server for DOS supports DDP to Caché, ISM, and DSM; the OMI protocol; and LAT terminal servers.

Summary
MSM-Server for DOS is the only implementation of M for PCs that runs in 32-bit mode under DOS. As a result, it supports more users and devices, and significantly outperforms all of the other M implementations running on PC systems under MS-DOS. An added benefit is DSM compatibility and true portability between platforms. Applications developed on MSM-Server for DOS can be moved to MSM-Server for UNIX platforms without any source code changes.

Networking capabilities are available with MSM-Server for DOS through use of the optional MSM-NET package. Using MSM-NET, client/server configurations can be implemented that use PCs as clients and as servers. Configurations can also be built using a combination of PCs, UNIX, or Windows NT systems, with any of these system types acting as clients, as servers, or as both client and server. Finally, a true Microsoft Windows graphical user interface (GUI) can be added to MSM-Server for DOS with the optional MSM-GUI package.

When MSM-Server for DOS is used in conjunction with the low-cost, high-performance PC systems available today, it offers an attractive alternative to large minicomputer systems. MSM-Server for DOS also provides an incremental building block approach to expanding systems with inexpensive, off-the-shelf components. System administration is also much easier because of the DOS environment. Finally, with the built-in resilient system features, MSM-Server for DOS provides a practical solution to configuring systems with non-stop availability.

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