Assembler Products (continued)

data management macros (continued)

multiple search / feedback 325 NOTE macro 299, 309

OPEN macro 297, 304

overview of programming elements 327 PIOCS 327

POINTS macro 300, 308

POINTW / POINTR macros 299, 308 processing a DAM File under MVS 324 processing a DAM File under VSE 324 PRTOV macro 296

READ macro 307, 313 record addressing 315 record addressing by ID 315 record addressing by KEY 316 record reference by ID 316 record reference by KEY 317 reference methods 316 RELSE macro 300, 306

track & record addressing 315 track addressing 315 TRUNC macro 300, 306

WAITF, OPEN & CLOSE macros 314 WRITE macro 307, 314

interrupt handling routines interval timer interrupts 287

operator communication interrupts 288 routine handling 287

TTIMER macro 288 wait handling 288

multitasking macros ATTACH/DETACH macros 283 ENTRYPOINT 284 RCB/ENQ/DEQ macros 286 WAIT/POST macros 285

system interface & macros

CANCEL macro 281

CDLOAD & CDDELETE macros 278 CHKPT macro 282 communication region 274 communication region simulation 276 COMRG & MVCOM macros 277 date 274

DUMP macro 280 EOJ macro 281 FETCH macro 278 GETIME macro 278 initiation 269

job name 275 linkage macros 271 LOAD macro 277

LOCK & UNLOCK macros 281 PDUMP macro 279

problem program area addresses 275 register conventions 269

save areas 270 termination 269

UPSI (User Program Switch Indicators) 275

Assembler Products (continued)

system interface & macros (continued) user program communication bytes 275 WTO & WTOR macros 278

virtual storage macros

FCEPGOUT, RUNMODE, VIRTAD & REALAD macros 290

GETVIS & FREEVIS macros 289 PAGEIN macro 290

PFIX & PFREE macros 290 RELPAG macro 290 SETPFA macro 290

VSAM macros

ACB macro 290

additional MVS VSAM ACB parameters 290 EXLST macro & EXCPAD routines 291 MVS VSAM additional SHOWCB fields 292 MVS VSAM CHECK macro 292

RPL macro (additional MVS parameters) 291 SHOWCB macro 292

VSAM error & reason code compatibility 292 VSE VSAM TCLOSE macro 292

asset management 471 methodology 471 overview 471 tasks 471

ASSGN statement 80, 83 ASSIGN clause 256 assignments 79 ASSOCIATE 339

asynchronous communication subsystem 188 ATTACH/DETACH macros 283

attachment options 236 automated

conversion 488 conversion process 490 migration services (AMS) 519 operations 37

operations tools 50 automatic restart 345

automating operational procedures 467 automation 25, 460

automation limits 489 availability of staff 12 availability of system 11

B

background customer migration example 529 backing up your system 410

backlevel hardware support 193 backout utility 174 BACKUP/RESTORE 124, 387 base elements for release 4 416 batch

&online program conversion 14 execution submission 162

job control 451 programming 171

Index 593

Page 617
Image 617
IBM OS/390 manual Index

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.