Senior Mainframe Systems Programmer - ISV
Posted Sep 17, 2026 · We last checked this listing on Oct 5, 2026
Likely interview questions for this role
Written from this job description, not a generic list. Each one notes what the interviewer is really checking.
About your past
Tell me about a conversion where data or configuration did not map cleanly between vendor tools.
What they are checking: Whether they handle the messy reality of migrations with careful testing and good records.
Tell me about a time you had to push a software vendor to fix a problem quickly.
What they are checking: Whether they can manage vendor support well, providing good diagnostics and escalating when needed.
What would you do
An ISV product abends right after a maintenance upgrade in production. Walk me through what you do.
What they are checking: Whether they stabilize the system first, gather dumps and evidence, and work with the vendor methodically.
How do you work with application teams and operations when a cutover affects their jobs and schedules?
What they are checking: Whether they coordinate across teams and communicate clearly so cutovers do not surprise anyone.
About the work
Walk me through installing a new ISV product on z/OS using SMP/E, from RECEIVE through ACCEPT.
What they are checking: Whether they truly know SMP/E and can install software safely without disrupting a running system.
You are leading a project to replace one vendor's tool with a competing product. How do you plan the migration?
What they are checking: Whether they can plan evaluation, conversion and cutover so the client sees no outage.
How would you run a proof of concept to compare two replacement tools fairly?
What they are checking: Whether they define clear test criteria tied to the client's needs instead of relying on vendor claims.
When do you use a USERMOD, and how do you keep track of them so they do not cause problems later?
What they are checking: Whether they manage local changes carefully, since forgotten USERMODs break future maintenance.
How do you use IBM utilities and JCL to troubleshoot an install or runtime problem?
What they are checking: Whether they have hands-on depth with z/OS tools to find problems quickly.
How do you keep many ISV products current on maintenance across several client systems?
What they are checking: Whether they have a disciplined maintenance process, which is central to a managed service provider.
What do you document after a product migration so someone else could support it?
What they are checking: Whether they leave good runbooks and records, since many people will support the system after them.
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As published by Ensono.