On Thursday, 27 July 2023 at 16:33:54 -0400, Paul Winalski wrote: > On 7/27/23, Noel Chiappa wrote: > >> Someone who's familiar with the 360 instruction set should be able to look >> at e.g.: >> >> and see how compatible it is. > > Interdata has some data types and instructions for manipulating them > not present in S/360. Circular lists, for example, and instructions > for CRC calculation. Yes, it's possible that both Interdata and RCA/UNIVAC/ICL instruction sets are supersets of the /360 instruction set. The only one I still remember is the LI (load immediate) instruction. The /360 did the same function with LA (load address), but IIRC that was RX (4 bytes), while LI was RR (2 bytes). > I didn't see anything about packed or zoned decimal support. > > So perhaps an extended subset of S/360. I'd have to do a side-by-side > comparison between this document and S/360 Principles of Operation to > determine the level of binary program compatibility, if any. But it > looks like it might be better than the HitchHiker's Guide to the > Galaxy adage: "almost, but not quite, entirely unlike tea." Yes, that seems reasonable. My guess was that binary compatibility wasn't a big issue in those days, since nearly all applications software was written only for specific installations. And of course licensing issues would preclude running IBM OS on the other machines. Greg -- Sent from my desktop computer. Finger grog@lemis.com for PGP public key. See complete headers for address and phone numbers. This message is digitally signed. If your Microsoft mail program reports problems, please read http://lemis.com/broken-MUA.php