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DCL (Digital Command Language) is a scripting language developed by Digital Equipment Corporation (DEC) in the 1970s. It was primarily designed for command and control functions in the VAX/VMS operating system. According to the Computer History Museum, DCL was instrumental in the success of DEC's VAX computers, as it provided a powerful, yet user-friendly interface. The language provided a standard method for tasks such as starting and stopping system services, managing files, and handling errors. Despite the decline of VAX systems, DCL remains in use today in OpenVMS systems, demonstrating its enduring utility and adaptability.

Ask the right questions secure the right DCL talent among an increasingly shrinking pool of talent.

First 20 minutes

General DCL app knowledge and experience

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

What is your experience with DCL?

I have been working with DCL for over 5 years. I have used it in various projects, including system administration, automation, and scripting.

How would you write a DCL script to automate a routine task?

First, I would identify the steps of the routine task. Then, I would write a DCL script using the appropriate commands and control structures to automate these steps. I would also include error checking and logging to ensure the script runs smoothly.

What are some common DCL commands you use?

Some common DCL commands I use include DIR, TYPE, DELETE, RENAME, COPY, and SET. These commands are used for file and directory management.

Describe the difference between DCL and other scripting languages.

DCL is specifically designed for the OpenVMS operating system, while other scripting languages like Python or Bash are more general-purpose. DCL has a unique syntax and command set that is tailored for system administration tasks on OpenVMS.

How would you handle errors in a DCL script?

I would use the ON control structure to catch and handle errors. This allows me to specify a block of code that will be executed when an error occurs. I can also use the MESSAGE command to display a custom error message.

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What you’re looking for early on

Does the candidate have a solid understanding of DCL commands?

Has the candidate demonstrated problem-solving skills?

Is the candidate familiar with the DCL development environment?

Can the candidate communicate effectively?

Next 20 minutes

Specific DCL 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.

What are some best practices for writing DCL scripts?

Some best practices include using comments to document the script, using meaningful names for symbols and labels, handling errors properly, and testing the script thoroughly before deployment.

Describe the difference between global and local symbols in DCL.

Global symbols are available throughout the entire DCL session, while local symbols are only available within the procedure where they are defined. Global symbols are defined using the SYMBOL command, while local symbols are defined using the LOCAL command.

How would you use DCL to interact with the OpenVMS file system?

I would use DCL commands like DIR, TYPE, DELETE, RENAME, and COPY to manage files and directories. I can also use the F$FILE function to retrieve file attributes.

What are some advanced features of DCL?

Some advanced features of DCL include the ability to create and manage subprocesses, the ability to interact with the OpenVMS system services, and the ability to use lexical functions to retrieve system information.

Describe the difference between a DCL procedure and a DCL command file.

A DCL procedure is a sequence of DCL commands that is stored in memory and can be executed by name. A DCL command file is a text file that contains DCL commands and can be executed using the @ command.

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At this point, a skilled DCL engineer should demonstrate strong problem-solving abilities, proficiency in DCL 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 DCL.

What does this simple DCL (Data Control Language) command do?
GRANT SELECT ON employees TO user1;
This command gives the 'user1' the permission to perform a SELECT operation on the 'employees' table.
What will be the result of this DCL command?
REVOKE UPDATE ON employees FROM user1;
This command removes the permission of 'user1' to perform an UPDATE operation on the 'employees' table.
What does this DCL command do?
GRANT SELECT, INSERT ON employees TO user1 WITH GRANT OPTION;
This command gives 'user1' the permission to perform SELECT and INSERT operations on the 'employees' table. Additionally, 'user1' can also grant these permissions to other users.
What will be the result of this DCL command?
REVOKE ALL PRIVILEGES ON employees FROM user1;
This command removes all the permissions of 'user1' on the 'employees' table.

Wrap-up questions

Final candidate for DCL 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 DCL application deployments. Inquire about their experience in handling system failures and their approach to debugging and troubleshooting.

How would you use DCL to manage subprocesses?

I would use the SPAWN command to create a subprocess. I can then use the SET PROCESS/IDENTIFICATION command to switch between the parent process and the subprocess. I can also use the STOP/IDENTIFICATION command to terminate a subprocess.

What are some DCL lexical functions you use frequently?

Some DCL lexical functions I use frequently include F$GETSYI, which retrieves system information, F$FILE, which retrieves file attributes, and F$SEARCH, which searches for files.

Describe the difference between the PIPE and SPAWN commands in DCL.

The PIPE command allows you to execute multiple DCL commands in a single command line, with the output of one command serving as the input for the next. The SPAWN command creates a new DCL subprocess and executes a command or procedure in that subprocess.

DCL application related

Product Perfect's DCL development capabilities

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

DCL Consultive assessments

DCL Application Conversion Assessment DCL Application Integration Assessment DCL Data & Database Integration Assessment

Custom DCL development projects

Custom DCL App Conversion DCL Custom App Development Process App UI Design for DCL Facelifts

Hiring guide for DCL Engineers

DCL Developer Hiring Guide

What you’re looking for early on

The ideal back-end app developer

What you’re looking to see on the DCL engineer at this point.

DCL Consultive assessments

Custom DCL development projects