Figure 2.

Changed Callable Services

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Callable

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Service

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Name

 

Description

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Support

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

initUSP

 

Ÿ

If

no

 

OMVS

 

segment

is

found

in

the

 

user'sDefault

 

 

 

 

 

profile, the initUSP service checks

theUSER/GROUP

 

 

 

 

BPX.DEFAULT.USER profile in the FACILITYOMVS

 

 

 

 

 

 

class. This profile may contain a userSegmentID in its

 

 

 

application

data

field

that

provides

a

default

 

 

 

OMVS

segment.

If

this

default is found, it is

 

 

 

used to set the UID,

HOME, and

PROGRAM

 

 

 

 

 

 

for

the

user.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ÿ If

no OMVS segment is

found

in

the

group

 

 

 

 

 

profile

 

of

 

the

user's

current

connect group,

the

 

 

 

initUSP

 

service

checks

the

 

 

 

 

 

 

 

 

 

 

 

BPX.DEFAULT.USER profile in the FACILITY

 

 

 

 

 

 

class.

This

 

profile

may

contain

a

group

ID

in

 

 

 

the

application

data field

that

provides a

default

 

 

 

OMVS

segment.

If

this

default

is

found,

it

is

 

 

 

used

to

set the GID

for

the

user.

 

 

 

 

 

Ÿ

If

any

 

defaults

are

used by initUSP, a bit is set

 

 

 

in the resulting USP to

indicate that this is the

 

 

 

default Open Edition security environment. Any

 

 

 

 

 

audit records written by subsequent RACF

 

 

 

 

 

 

callable

 

services

reflect

this.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

getGMAP

 

Ÿ

If

getGMAP

is

given

a

group ID as Defaultinputand

 

 

 

the

corresponding

GROUP

profile

has

noUSER/GROUP

 

 

 

OMVS segment, getGMAP checks the

 

 

 

OMVS

 

 

 

 

 

 

BPX.DEFAULT.USER profile in the FACILITYSegment

 

 

 

 

 

class. This profile may contain a group ID in its

 

 

 

application

data

field

that

provides

a

default

 

 

 

OMVS

segment.

If

this

default

is

found,

its

GID

 

 

 

is

returned to the issuer of getGMAP.

 

 

 

 

 

 

 

 

 

getUMAP

 

Ÿ If

getUMAP is given a user ID as Defaultinputand the

 

 

 

corresponding

USER

profile

has

no

OMVS USER/GROUP

 

 

 

segment,

 

getUMAP

checks

the

 

 

 

 

OMVS

 

 

 

 

 

 

BPX.DEFAULT.USER profile in the FACILITYSegment

 

 

 

 

 

class. This profile may contain a user ID in its

 

 

 

application

data

field

that

provides

a

default

 

 

 

OMVS

segment.

If

this

default

is

found,

its

UID

 

 

 

is

returned

 

to

the

issuer

of

getUMAP.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Class Descriptor Table (CDT)

Figure 3 lists new classes provided in the IBM-supplied class descriptor (ICHRRCDX). The class names are general-use programming interfaces (GUPI ICHEINTY and RACROUTE. There is a set of entries corresponding to the classes added in the IBM-supplied router tables.

12 OS/390 V2R4.0 Security Server (RACF) Planning: Installation and Migration

Page 32
Image 32
IBM OS/390 manual Class Descriptor Table CDT, Gid, Uid

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.