I am a former mainframe computer operator from back in the IBM System/370 days. My first experience with COBOL was on a System 370/125 (DOS/VS Full ANSI COBOL) and later the IBM 4341 Group II under DOS/VSE. I've worked with a little VSAM - at least that which was available on early /VSE systems. I have also operated at other sites. My last experience was on an ES/9000 Model 9121 under an early version of VSE/ESA under VM/ESA, but that was as an operator. I am fairly familiar with DOS/VS JCL - enough to develop some simple applications and to get them to run. This may sound a bit strange, but I use DOS/VS today!
Unfortunately today, stuff like this is a hobby. My skill set is very archaic (I hop no one here looks down on this!), and the version of COBOL I use is the 1968 ANS COBOL which lacks VSAM support (it's DOS/360 vintage!). The closest thing therefore to a VSAM KSDS I can use are ISAM files.
Nevertheless, I hope to learn some things here and to enjoy myself! Best wishes to everyone here!!!