The IBM VSE/ESA Operating System is in use by thousands of customers with millions of users worldwide. It meets the host computing needs of these customers and users with high performance transaction processing, client-server, and efficient batch processing for these users.

VSE/ESA began in the 1960s as a small, efficient operating system for smaller IBM System/360 mainframe computers, called DOS. Over the years capabilities were added to the system to support enhancements in the hardware processors -- first, virtual storage (DOS/VS), then extensions for larger and faster processors (DOS/VSE), and more recently, full support of Enterprise Systems Architecture processors with large main storage and multiple instruction processors (VSE/ESA).

You can find more about VSE/ESA at the IBM VSE/ESA site and you can find user discussions about VSE/ESA and related topics at the VSE-L discussion site hosted by Lehigh University.

If you want to know how to have a CICS subsystem in your VSE/ESA environment with fast and stable response time, using as little of your system's resources as possible to do so, you've found the right place here!

• Basic VSE terminology and jargon
• Transaction Processing overview
• File and Database support
• Other critical functions