The current supported levels of VTAM on VSE are V3R4 and V4R2. VSE VTAM V4R2 is available in three different functional level packages:

∙

∙

∙

Client/Server

MultiDomain

InterEnterprise

Packages are priced according to the amount of function provided and are password enabled via the VTAM start procedure.

The eNetwork Communications Server for OS/390 is only available in a single flavor, which is the functional equivalent of the high end VSE/VTAM package (InterEnterprise). The four main differences between VSE/VTAM and OS/390 VTAM are as follows:

1VSE/VTAM supports Integrated Communications Adapters (ICAs) on 9221, 937X and 43XX processors.

These adapters are not supported by OS/390 VTAM, and alternate methods of connecting your network to a channel must be found. The various ICAs and possible alternatives follow:

∙Multi-Protocol Communication Subsystem (6251 - 6254)

￿IBM eNetwork Communications Server for OS/2 (prod #4301114) or Windows NT (prod #4231747) with a Wide Area Connector (WAC) card or Multi-Protocol Adapter (MPA) card can provide support for SDLC communication lines.

￿The 3172 Interconnect Controller, in addition to LAN connectivity can provide support for up to 32 SDLC communication lines.

￿The 2210 and/or 2216 multi-protocol routers can be used to support multiple line protocols including SDLC. These routers can be attached to the host via a LAN gateway (such as the OSA-2 adapter). In addition, the 2216 can be channel attached much like the 3172.

￿A 37XX controller with NCP can provide support for SDLC line protocols for installations required to support larger numbers of remote devices.

∙Asynchronous Communication Subsystem (6241 - 6244)

￿A 37XX controller with NCP/PEP can provide connectivity for asynchronous Start/Stop (TTC2) devices.

∙ASCII Subsystem (6245 - 6248)

∙

∙

￿Although MVS/VTAM supports this adapter, if the migration includes a processor upgrade, a replacement for this adapter must be found. Options include the 3174 with an Asynchronous Emulation Adapter (AEA) providing support for ASCII devices in 3270 emulation mode.

￿IBM eNetwork Communications Server for OS/2 (prod #4301114) or Windows NT (prod #4231747) with a Multi-Protocol Adapter (MPA) card can provide support for ASCII devices in 3270 emulation mode.

Token-Ring Adapter (6139/6140)

Ethernet Adapter (6135)

188VSE to OS/390 Migration Workbook

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IBM manual VSE to OS/390 Migration Workbook
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OS/390 specifications

IBM OS/390, a versatile operating system, was a cornerstone in enterprise environments and played a pivotal role in mainframe computing. Released in the mid-1990s, OS/390 combined the strengths of IBM's MVS (Multiple Virtual Storage) with new features and enhancements, targeting scalability, reliability, and performance in demanding business applications.

One of the key features of OS/390 was its robust support for multiple users and processes. The system allowed thousands of concurrent users to access applications and data, ensuring high availability and minimizing downtime—a critical requirement for many large organizations. This scalability was supported through various enhancements in memory management and processor scheduling, enabling optimal resource allocation across diverse workloads.

OS/390 was known for its superior workload management capabilities. The Workload Manager (WLM) component allowed administrators to define service policies, specifying how system resources would be allocated according to the priority of tasks. This ensured that critical business processes received the necessary resources while less critical tasks were managed more flexibly.

Another significant characteristic of OS/390 was its commitment to security. The operating system provided comprehensive security features, including user authentication, data encryption, and auditing capabilities. This focus on security was vital for organizations handling sensitive data, ensuring compliance with regulations and safeguarding against unauthorized access.

OS/390 also supported advanced technologies that facilitated integration and development. The system included features like the IBM CICS (Customer Information Control System) for transaction processing and IMS (Information Management System) for database management. These technologies allowed organizations to build robust, high-performance applications tailored to specific business needs.

The ease of network integration was another strength of OS/390. With the advent of the Internet and global connectivity, OS/390 systems could easily interface with various network protocols, enabling businesses to operate in a connected world. This inclusion paved the way for many organizations to expand their capabilities and offer new services, driving digital transformation.

In conclusion, IBM OS/390 represented a significant advancement in mainframe technology, combining scalability, security, and robust workload management. Its rich feature set and support for critical enterprise applications solidified its role as a vital component of many organizations' IT infrastructures, ensuring they could meet their operational challenges head-on while supporting future growth. As technology continues to evolve, the legacy of OS/390 remains influential in the realm of computing.
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