device (continued)

 

 

 

DITTO (continued)

 

 

 

 

 

control

448

 

 

 

 

function code synonyms

384

 

information 329

 

 

 

functions not recommended

383

 

migration 36

 

 

 

obsolete batch keywords

384

 

status display

448

 

 

 

obsolete functions

382

 

 

 

supported by OS/390

402

 

 

release compatibility

381

 

 

DFDSS

23

 

 

 

 

 

security

385

 

 

 

 

 

 

DFHMSCAN utility 152

 

 

 

DL/I

 

 

 

 

 

 

 

 

DFHSM

23

 

 

 

 

 

access alternatives

175

 

 

 

DFSDSdss

101

 

 

 

 

ACCESS statement

170

 

 

 

DFSMS FIT

102

 

 

 

calls

172

 

 

 

 

 

 

 

DFSMS implementation

102

 

 

CEETDLI

366

 

 

 

 

 

 

DFSMS naming conventions

543

 

CICS

154

 

 

 

 

 

 

DFSMS/MVS diagnosis

476

 

 

DL/I parameter statement

174

 

DFSMSdfp

 

 

 

 

IMS/ESA access alternatives

175

 

analyzing catalogs for errors and

IMS/VS DB differences

169

 

 

synchronization

476

 

 

IMSCOMP parameter

16

 

 

 

catalog recovery

476

 

 

introduction

169

 

 

 

 

 

checking VSAM KSDS for structural errors 477

Multiple Partition Support

178

 

DFSMSdss 478

 

 

 

PSB

171

 

 

 

 

 

 

 

DFSMShsm

477

 

 

 

DL/I & IMS/VS DB differences

169

 

DFSMSrmm

478

 

 

 

batch programming

 

 

 

 

 

DFSMSdfp

101, 387, 476

 

 

assembler language calls

173

 

DFSMSdss

387, 397, 456, 478

 

CHKP calls

172

 

 

 

 

 

DFSMSdss - OS/390 functions

398

command-level coding (HLPI)

171

DFSMShsm

101, 387, 477

 

 

field level sensitivity

172

 

DFSMSrmm

101, 478

 

 

 

GSCD and/or GSTA calls

172

 

DFSORT/VSE control statements

379

Interactive Macro Facility (IMF)

171

DFSORT/VSE migration considerations 379

NI status codes

172

 

 

 

diagnosing system problems

473

 

PCB after GE status

172

 

 

diagnostic reference publications

478

RPG II

171

 

 

 

 

 

differences

 

 

 

 

 

statement compatibility

172

 

DL/I & IMS/VS DB 169

 

 

Data Base Descriptor (DBD)

170

 

in testing philosophy

419

 

 

database portability

 

 

 

 

 

JCL and JECL

241

 

 

 

alternate DL/I and IMS/ESA access 175

POWER-JES2

209

 

 

 

unloading and reloading the database 176

direct access file definition

311

DL/I Multiple Partition Support (MPS) 178

direct access file processing

318

introduction 169

direct access method (DAM)

15

MVS system requirements 170

disk logging 174

 

operations

disk storage considerations 97

backout utility/disk logging

174

DISP in JCL 344

DL/I parameter statement

174

display

RESTART with CHKP 173

 

areas 445

UPSI 174

 

console management 444

 

Program Specification Block (PSB) 171

consoles

444

 

 

utilities

 

 

statement

259

 

 

REWIND option for reorganization utilities 173

status of devices

448

 

secondary index creation

173

system status

447

 

DLBL statement

83

 

work on system

449

 

documentation 40, 407, 412

 

DISPLAY statement

259, 447

 

DOS

 

 

Distributed Queue Management (DQM)

204

compiler specific options 335

DITSECUR exit

385

 

 

PL/I 356

 

 

DITTO 244

 

 

 

 

specific options

343

 

batch keywords not recommended

385

storage management 345

 

code synonyms

384

 

DOS/VS COBOL

356

 

compatibility

381

 

CICS programs

252

 

ESA security

385

 

compiler options not available

260

Index 599

Page 623
Image 623
IBM OS/390 manual Device Ditto

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.