Driving the Future of Mainframe Innovation | VSE

Why 21CS
Products
- Our Products
  - SENTINELⁿ
    Comprehensive change management tool for z/OS
  - STRATUSⁿ
    Cloud object storage for z/OS | 21CS
  - Tape/Assist®
    Seamlessly migrates z/OS tape data
  - TRANSVERSEⁿ
    End-to-end, non-disruptive z/OS data migration
  - VECTORⁿ
    Modern, simplified dataset transfers
  - VSEⁿ
    Enhanced VSE experience compatible with previous versions
- What's Next
  - VERIFIⁿ
    Modern, adaptable JCL checker
  - OPTIMAⁿ
    The next generation of mainframe performance analytics
- Trusted IBM Partner
  - IBM Product Portfolio
- 21CS Partners
  - Global Partnerships
A First Look at OPTIMAn's New Reporting Interface

OPTIMAn's new reporting interface brings AI-assisted, plain-language answers to IBM Z performance ...
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Solutions
- Our Solutions
Talk to a Mainframe Expert

Partner with experts who understand mainframe challenges and opportunities.
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Resources
- Articles
- Events

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VSEn: A Bold Investment in the Future
In 2021, I had the privilege of being part of one of the boldest decisions in our company's history to date.

IBM Z
July 27, 2026
VSEn on IBM z17: The Only VSE Operating System Ready for What's Next
IBM z17 is here. For organizations running VSE workloads, the path forward runs through one operating system: 21CS VSEn 6.3 and 6.4.

IBM Z
July 22, 2026
21CS Announces VSEn 6.4
21CS is excited to announce the upcoming release of VSEn 6.4 with planned availability on October 15, 2025. This release reflects our strong commitment to the VSEn community by delivering valuable...

News
September 16, 2025
21CS Brings VSEn 6.3 to the New IBM z16 Single Frame and Rack Mount Models
We are excited to collaborate with IBM as the company announced its new IBM z16 single frame and rack mount options available globally on May 17, 2023. Powered by the IBM Telum processor, these...

News
July 30, 2023
IBM z16: The Ideal Platform for VSE Business Needs
by Gonzalo Muelas Serrano

IBM Z
May 9, 2022
21CS Enters Agreement to License z/VSE Operating System
by Gonzalo Muelas Serrano 21CS recognizes that organizations using IBM z/VSE value their mission-critical data. The operating system is typically used by IBM Z clients whose environments...

VSE
June 1, 2021