Using Externally Described WORKSTN Files

Processing an Externally Described WORKSTN File

When an externally-described WORKSTN file is processed, the OS/400 sys transforms data from the program to the format specified for the f the data. When data is passed to the program, the data is transf format used by the program.

The OS/400 system provides device-control information for processing input

operations for the device. When an input

record is

requested from

OS/400 system issues the request,

and then removes device-control infor

from the data before passing the

data to the program. In additio

system can

pass

indicators to the

program

indicating

which fields, or

the record

have

been changed.

 

 

 

When the program requests an output operation, it passes the output OS/400 system. The OS/400 system provides the necessary device-control mation to display the record. It also adds any constant information record format when the record is displayed.

When

a

record

is passed to a program,

the fields are arranged in

they

are specified

in

the

DDS.

The

order

in which

the

fields are

on the

display

positions

(line

numbers

and

position) assigned to the f

DDS. The order in which the fields

are

specified

in the

DDS and t

they

appear on

the

screen need

not

be

the

same.

 

 

For more information on processing WORKSTN files, see “Valid WORKSTN File Operations” on page 341.

Using Subfiles

Subfiles can be specified in the DDS for a display-device file to multiple records of the same type on the display. (See Figure 166 o subfile is a group of records that is read from or written to a example, a program reads records from a database file and creates output records. When the entire subfile has been written, the prog entire subfile to the display device in one write operation. The w change data or enter additional data in the subfile. The program t entire subfile from the display device into the program and process in the subfile individually.

Records

that you want

to be included in a subfile are

specified

 

file.

The number

of

records that can

be

included

in a

subfile must

in

the

DDS.

One

file

can

contain

more

than

one subfile,

and

up

to

1

be

active

concurrently.

Two subfiles can be displayed

at

the

same

 

The DDS for a subfile

consists of two record formats:

a

subfile-rec

subfile control-record format. The subfile-record format

contains

the

 

that

is

transferred

to

or

from

the

display file

under

control

of

t

record

 

format. The

subfile control-record format causes the physical

control

operations

of

a

subfile

to

take

place.

Figure 167

on page 337

example

of the

DDS

for

a subfile-record

format,

and Figure 168 on pa

shows

an

example

of

the

DDS for

a

subfile control-record

format.

For a description of how to use subfileDDSkeywords,Reference.s e the

Chapter 18. Using WORKSTN Files335

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IBM AS/400 manual Processing an Externally Described Workstn File, Using Subfiles
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AS/400 specifications

The IBM AS/400, now known as the IBM iSeries, is a midrange computer system that has been a cornerstone of enterprise computing since its introduction in 1988. Designed to provide a robust platform for business applications, the AS/400 is celebrated for its reliability, scalability, and integrated database capabilities.

One of the key features of the AS/400 is its Integrated Operating Environment, which blends hardware and software resources seamlessly. This integration allows businesses to execute diverse workloads, ranging from traditional applications to modern web-based services, all on a single platform. The operating system, OS/400 (now IBM i), offers a rich set of APIs and tools for developers, simplifying application development and management.

Another standout characteristic of the AS/400 is its built-in database, DB2 for i. This powerful relational database management system allows for efficient data handling and provides advanced features such as support for SQL, XML, and JSON, making it easier for businesses to manage their data and integrate it with other systems. The database's tight integration with the operating system enables high performance and security.

In terms of scalability, the AS/400 can accommodate small businesses as well as large enterprises, with the ability to support hundreds of users simultaneously. Its architecture allows for easy upgrades in hardware, meaning that organizations can scale their systems without replacing the entire infrastructure.

Security is another critical attribute of the AS/400. With a sophisticated security model, it offers built-in user authentication, access control, encryption, and auditing capabilities to protect data and applications from unauthorized access.

The AS/400 also supports multiple programming languages, including RPG, COBOL, Java, and PHP, giving organizations the flexibility to choose the development tools that best fit their needs. This diversity helps maintain legacy applications while also developing new ones that leverage modern technologies.

Moreover, the platform supports both traditional green-screen interfaces and modern graphical user interfaces, allowing organizations to transition smoothly into contemporary user experience paradigms.

Overall, the IBM AS/400 stands out as a resilient, flexible, and secure computing platform that enables organizations to effectively manage their business operations, streamline processes, and adapt to changing market demands. Its unique combination of integrated features and capabilities ensures that it remains relevant in today's fast-paced technology landscape.
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