The MVS TIME macro has an additional operand MIC,address that causes the time of day to be returned in the eight-byte area specified by the address. The time of day is in microseconds, with bit 51 equivalent to one microsecond.

Register 0 contains 0, and register 1 contains the date.

System

Operand

 

Register Content

VSE

STANDARD

H HM MS S

 

MVS

DEC

 

HH MM SS th

 

VSE

BINARY

 

seconds

 

MVS

BIN

 

hundredths of a second

VSE

TU

 

1/306 of a second units

MVS

TU

 

26 micro second units

H = hours

 

M = minutes

S = seconds

t = 0.1 seconds

h = 0.01 seconds

 

Figure 30. VSE and MVS Time Degrees of Precision

The MVS TIME macro returns the date and time into a work area when LINKAGE=SYSTEM is specified. The date (Julian or Gregorian) and the time are returned in packed decimal digits.

Example:

TIME DEC,OUTAREA,DATETYPE=YYYYMMDD,LINKAGE=SYSTEM

. . . .

OUTAREA DS

0XL16

 

HHMMSSHH DS

X′12305919′

TIME OF DAY

DS

XL4

filler

YYYYMMDD DS

X′19980323′

DATE

DS

XL4

filler

PDUMP Macro

The VSE PDUMP macro provides a hexadecimal dump of the general registers and of the main/virtual storage area contained between the two address parameters. The output is automatically written on the device assigned to SYSLST with 121-byte records.

The MVS SNAP macro provides you with the same dump facility. However, you must supply the data set (via the DD statement) on which the output is written and a DCB for the data set must be opened before the SNAP macro is used.

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IBM OS/390 VSE Standard HM MS S MVS DEC, VSE Binary, Mvs Bin, Time DEC,OUTAREA,DATETYPE=YYYYMMDD,LINKAGE=SYSTEM, XL4, Date

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.