Would't have thought about this as a grey area. But sure, you make a valid point. Basic On-Topic decisions are not only about age and out-of-production (*1) but a soft membrane tethered also at obscurity and what I would call coolness in lack of a better word. **Plus**, and that's maybe most important, intention/purpose of a question. I would think your question may tick all of these requirement. Beside asking for origins, which always works, it's a software question, which nicely can be tied to older eras. VTAM was introduced ca. 1976 (after being vapourware for some time), so one can nicely ask for 1976 VTAM - or better even for BTAM, which had to solve the same issue, even more direct :)) So go ahead and ask. --- In case of IBM mainframes it may be rather relevant to distinguish between - OS, - Architecture, and - Implementation/specific family and model. In case of mainframes this is often blurred into using one term, but meaning some of the other. For example people like to say z/OS when in fact talking about z/architecture or a specific model as if it would be clear. That isn't. So make sure what exactly you're asking about. AMODE 64 being a nice example. While z/OS supports it native, it's not an OS feature buy a hardware one. The same Hardware can run other software that uses this feature. Being introduced in ca. 2000 I would think questions about compatibility / complications with AMODE 64 could as well qualify. Kinda like asking about Y2K problems 20 years later :)) --- On a more general level I could not think of many borderline /360ff questions. Either it's really about modern API (or instruction) and clearly off topic, or more likely something that is around since 40+ years --- Now, for the translation part, you may as well look at [BTAM][1], as VTAM is more of an additional abstraction layer, hiding more of the nitty gritty details. In BTAM one can still direct access the translate tables (Macro TRNSLATE) for example RASA/SASA for 3270 ASCII/EBCDIC translation. But you might be surprised how much is stil done 'by hand'. --- *1 - In the end the main reason for this cut off is to redirect todays questions into SE areas which are more appropriate. [1]: http://www.bitsavers.org/pdf/ibm/360/os/btam/GC30-2004-6_OS_BTAM_Sep72.pdf