ACC Specifies that the problem program accepts the block causing the error. This action can be specified when a data set is opened for INPUT, RDBACK, UPDAT, or OUTPUT (OUTPUT applies to printer data sets only).

SKP Specifies that the block that caused the error is skipped. Specifying SKP also causes the buffer associated with the data block to be released. This function can be specified when a data set is opened for INPUT, RDBACK, or UPDAT.

ABE Specifies that the error results in the abnormal termination of the task. This action can be specified when the data set is opened for INPUT, OUTPUT, RDBACK, or UPDAT.

If you omit the EROPT operand, the ABE action is assumed.

READ Macro

 

 

filename ,SQ,

area length

 

VSE

READ

(1)

(0)

(r1)

 

 

 

 

 

S

 

 

 

 

 

 

 

 

 

decbname,SF,

dcbaddress

,

area address ,

MVS

READ

 

(2-12)

 

(2-12)

 

 

 

length

 

 

 

 

 

(2-12)

 

 

 

 

 

′ S′

 

 

 

 

 

 

 

 

Notes:

1.If the OPEN macro specifies UPDAT, you must use the execute form of the READ macro.

2.You must test the input operation for completion by using the CHECK macro instruction.

WRITE Macro

VSE

WRITE

filename ,

UPDATE ,

area

,

length

 

 

(1)

SQ

(0)

 

(r)

 

 

 

 

 

 

 

 

MVS

WRITE

decbname,SF,

dcbaddress

area

address

length

 

 

 

(2-12)

, (2-12)

 

, (2-12)

 

 

 

 

 

 

 

′ S′

 

 

 

 

 

 

 

 

Notes:

1.If the OPEN macro specifies UPDAT, you must use the execute form of

WRITE.

2.You must test the output operation for completion by using the CHECK macro.

CHECK Macro

VSE

CHECK

filename

control-address

 

 

(1)

,

(0)

 

 

 

 

 

MVS

CHECK

decbaddress

 

,DSORG= IS

 

 

(1-12)

 

ALL

 

 

 

 

 

Chapter 13. A s s e m b l e r 307

Page 331
Image 331
IBM OS/390 manual Read Macro, Write Macro, Check Macro

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.