Hiring guide for IBM RPG III. Engineers

IBM RPG III. Developer Hiring Guide

IBM RPG III is a high-level programming language, introduced by IBM in 1978 for use on its System/38 midrange computers. It's an iteration of Report Program Generator (RPG), originally developed in the 1960s to facilitate business data processing. This third-generation language featured structured programming capabilities and enhanced data handling, significantly improving upon its predecessors. Despite the advent of more modern languages, RPG III remains in use today, particularly within legacy systems. The information is referenced from IBM's official archives and various scholarly articles on computer programming history.

Ask the right questions secure the right IBM RPG III. talent among an increasingly shrinking pool of talent.

First 20 minutes

General IBM RPG III. app knowledge and experience

The first 20 minutes of the interview should seek to understand the candidate's general background in IBM RPG III. application development, including their experience with various programming languages, databases, and their approach to designing scalable and maintainable systems.

How would you define the term 'RPG' in the context of IBM RPG III?
RPG stands for Report Program Generator. It's a high-level programming language that was developed by IBM for business applications. It's mainly used for data-centric applications on IBM i operating systems.
What are the key differences between RPG II and RPG III?
RPG III introduced several improvements over RPG II, including enhancements to the calculation specifications, the addition of built-in functions, and support for structured programming with IF/ELSE/ENDIF and DO/ENDDO structures.
Describe the difference between a fixed format and free format in RPG III.
In fixed format, each statement is written in a fixed number of columns with specific positions for operation codes, factors, and results. In free format, introduced in later versions of RPG, statements can be written more flexibly, similar to other modern programming languages.
How would you declare a variable in RPG III?
Variables in RPG III are declared in the Definition Specification (D-spec) section of the program. For example, DName+++++++++++ETDsFrom+++To/L+++IDc.Keywords++++++++++++++, where D is the specification type, Name is the variable name, and ETDsFrom/To are the from and to positions of the variable.
What are the types of indicators in RPG III and what are their uses?
Indicators in RPG III are boolean variables that can hold the values *ON or *OFF. They are used for conditional processing, control level indicators, and overflow indicators among others. They are named by their positions, from 01 to 99 and LR.
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What you’re looking for early on

Does the candidate have a solid understanding of IBM RPG III language?
Has the candidate demonstrated problem-solving skills?
Does the candidate show good communication skills?
Does the candidate have experience with systems analysis and design?

Next 20 minutes

Specific IBM RPG III. development questions

The next 20 minutes of the interview should focus on the candidate's expertise with specific backend frameworks, their understanding of RESTful APIs, and their experience in handling data storage and retrieval efficiently.

How would you perform error handling in RPG III?
Error handling in RPG III can be done using the 'E' operation extender in the I/O operation codes. When an error occurs during the operation, the operation does not abort, and the *INLR indicator will be set on. The program can then check the status code to determine the appropriate action.
Describe the difference between SETON and SETOFF in RPG III.
SETON and SETOFF are used to set the value of indicators in RPG III. SETON sets the indicator to *ON, while SETOFF sets the indicator to *OFF.
What are the primary functions of the MOVE operation in RPG III?
The MOVE operation in RPG III is used for data manipulation. It moves the value from the factor 2 field to the result field. It can also be used to move data between fields of different types, with automatic conversion.
How would you write a subroutine in RPG III?
A subroutine in RPG III is written starting with a BEGSR operation code followed by the subroutine name, and ending with an ENDSR. The subroutine can be called from the mainline code or other subroutines using the EXSR operation code followed by the subroutine name.
What are the uses of the SCAN operation in RPG III?
The SCAN operation in RPG III is used to search for a string within another string. It sets the index of the position where the string was found, or zero if not found.
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The ideal back-end app developer

What you’re looking to see on the IBM RPG III. engineer at this point.

At this point, a skilled IBM RPG III. engineer should demonstrate strong problem-solving abilities, proficiency in IBM RPG III. programming language, and knowledge of software development methodologies. Red flags include lack of hands-on experience, inability to articulate complex concepts, or unfamiliarity with standard coding practices.

Digging deeper

Code questions

These will help you see the candidate's real-world development capabilities with IBM RPG III..

What does the following simple RPG III code do?
C MOVE 'Hello, World!' MESSAGE
This code moves the string 'Hello, World!' into the variable MESSAGE, then calls the subroutine WRITE_MESSAGE. The subroutine WRITE_MESSAGE would then typically display or print the message.
What will be the output of the following RPG III code?
C                   IF %FOUND
C                   EVAL CUSTNAME = 'John Doe'
C                   UPDATE CUSTMAST
C                   ENDIF
The code searches the CUSTMAST file for a record with CUSTNO. If a record is found, it sets the CUSTNAME field to 'John Doe' and updates the record in the CUSTMAST file. If no record is found, nothing happens. The output will be the updated 'John Doe' in the CUSTNAME field if a record was found.
What does the following RPG III code do, which deals with array manipulation?
C     1 DO 5 I
C       ARR, I ADD 1 ARR, I
This code loops over the first 5 elements of the array ARR and increments each element by 1. The ADD operation adds 1 to each element of the array.
What does the following RPG III code do, which is related to threading or concurrency?
The code locks the EMPFILE file, searches for a record with EMPID. If a record is found, it increases the SALARY field by 1000 and updates the record in the EMPFILE file. Then it unlocks the EMPFILE file. This ensures that the update operation is completed without interference from other threads.

Wrap-up questions

Final candidate for IBM RPG III. Developer role questions

The final few questions should evaluate the candidate's teamwork, communication, and problem-solving skills. Additionally, assess their knowledge of microservices architecture, serverless computing, and how they handle IBM RPG III. application deployments. Inquire about their experience in handling system failures and their approach to debugging and troubleshooting.

How would you handle arrays in RPG III?
Arrays in RPG III are declared in the Definition Specification, and can be processed using operation codes such as MOVEA for moving elements, and SORTA for sorting the array. The index of the array can be set and retrieved using the %INDEX built-in function.
Describe the difference between a READ and a CHAIN operation in RPG III.
READ operation in RPG III is used to read records sequentially from a file, while CHAIN operation is used to read a record directly using a key or relative record number.
What are the steps to debug a program in RPG III?
Debugging a program in RPG III typically involves setting breakpoints at specific lines of code, running the program in debug mode, and then examining the program variables and flow at each breakpoint.

IBM RPG III. application related

Product Perfect's IBM RPG III. development capabilities

Beyond hiring for your IBM RPG III. engineering team, you may be in the market for additional help. Product Perfect provides seasoned expertise in IBM RPG III. projects, and can engage in multiple capacities.