VSE DTFDI

MVS DCB DSORG=PS

DEVADDR = SYSxxx

DDname (in DD statement)

IOAREA1 = xxxxxxxx

BUFNO =

1

or

 

 

IOAREA! = xxxxxxxx BUFNO = 2 or more

IOAREA2 = xxxxxxxx

 

 

EOFADDR = xxxxxxxx

EODAD = xxxxxxxx

ERROPT = xxxxxxxx

SYNAD = xxxxxxxx

ERROPI = IGNORE

EROPI = ACC

SKIP

 

SKP

 

 

ABE

 

MACRF =(G...)

 

= (p...)

 

RECFM = FA

 

= FM

 

BLKSIZE = nnnn

IOREG = (r)

MACRF = (..L..)

RECSIZE = nnn

LRECL = nn

SEPASMB = YES

User must code the DCB

WLERR = xxxxxxxx

SYNAD = xxxxxxxx

Figure 37. Comparison of DTFDI and DCB macros

13.2.6.9 LIOCS Console File Definition

The DTFCN has no equivalent in MVS because reading and writing via the console is not handled at the GET/PUT level. MVS provides the WTO macro for writing on the console and the WTOR macro for writing a message and reading a reply. Therefore, you must replace a PUT macro for the console by either a WTO macro to display a message or a WTOR macro for displaying a message and reading a reply.

Do not display messages on the console unless they are necessary. The system writes many messages to the operator, and extra messages could lead to confusion and hinder the performance of the installation.

MVS

WTO WTOR

′ message′

message′ , reply address, reply length, ecbaddress

(2-12)

(2-12)

(2-12)

13.2.6.10LIOCS Sequential File Definition on Direct Access

Devices

Devices In VSE and MVS, sequential DASD files are processed in the same way.

OPEN Macro

VSE

OPEN(R)

filename

,...

 

 

 

 

(r1)

 

 

 

 

 

 

 

 

 

MVS

OPEN

dcbaddress

,

option1, option2

,...

 

 

(2-12)

 

 

 

 

 

 

 

 

 

304VSE to OS/390 Migration Workbook

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Image 328
IBM OS/390 manual Liocs Console File Definition, Liocs Sequential File Definition on Direct Access Devices, Recfm = FA

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.