VSE DTFPR

MVS DCB DSORG=PS

DEVADDR = SYSxxx

DDname (in DD statement)

IOAREA1 = xxxxxxxx

BUFNO = 1,MACRF =(..M..)

or

 

IOAREA1 = xxxxxxxx

BUFNO = 2 or more

1OAREA2 = xxxxxxxx

 

ASOCFLE = xxxxxxxx

UNIT=AFF=ddname (in DD statement)

BIKSIZE = nnn

BLKSIZE = nnn

CONTROL = YES

MACRF = (PC)

CTLCHR = YES

RECFM = (..A)

ASA

(...M)

DEVICE = nnnn

UNIT = (in DD statement ) (1)

ERROPT = xxxxxxxx

SYNAD = xxxxxxxx

FUNC = xxxx

DEVD=(..,..,..,FUNC = xxxxxx)

IOREG =(r)

MACRF= (..L..)

PRINTOV = YES

Use PRTOV

RECFORM = xxxxxx

RECFM = xxx

RECSIZE = (r)

LRECL = nn (2)

SEPASMB = YES

User must code the DCB

WORKA = YES

MACRF = (..M..)

1. By specifying U N I T = you are using dedicated I/O. A preferable

alternative is to use SYSOUT=A.

2. For output of undefined records, you must provide the length

of the records in a two-byte field (DCBLRECL) within the DCB.

LRECL must be provided for fixed-length and variable-length

records.

 

 

Figure 34. Comparison of the DTFPR and DCB Macros

13.2.6.7 LIOCS Tape File Definition

In VSE and MVS, you process sequential tape files in the same way.

OPEN Macro

VSE

 

OPEN(R)

filename ,...

 

 

 

(rl)

 

 

 

 

MVS

 

OPEN

dcbaddress , (options) ....

 

 

 

(2-12)

 

 

 

 

Options

 

 

 

 

Option 1

Option 2

QSAM

INPUT

,REREAD

 

 

OUTPUT

,LEAVE

 

 

RDBACK

,DISP

 

 

INPUT

,REREAD

 

 

OUTPUT

,LEAVE

BSAM

RDBACK

,DISP

 

 

INOUT

 

 

 

OUTIN

 

Chapter 13. A s s e m b l e r 297

Page 321
Image 321
IBM OS/390 manual Liocs Tape File Definition, Control = YES Macrf = PC Ctlchr = YES, Printov = YES, Sepasmb = YES

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.