That's common in the mainframe world. Unisys (ex Univac) still has its Dorado mainframes binary compatible with the Univac 1100 released in 1962.

I think I remember reading a while back that System/360 binaries can still run on modern Z/architecture mainframes.

Yup, that’s the example I cited above.

Oops, missed that, I came in from the comments link.

I thought the Unisys mainframes have been running emulated on X86/X86-64 for a while? I assume they have some sort of binary translator.

Yes, you got it right. The Dorados now run a binary emulator on top of a microcomputer (x86_64) architecture, while IBM Z (itself essentially a 64-bit S390 arch) kept a mainframe configuration.

What's a DE? Also did they tell you what the program did?

Other systems that will run or automatically translate > 30 yr old binaries:

- I believe IBM i on POWER {i5/AS400} will run stuff from System 38 (1980).

- HPE Nonstop (aka Tandem Guardian ) on X86-64 will run or translate binaries from the original proprietary TNS systems (late 1970s) and MIPS systems (1991).

Distinguished Engineer?

Bingo.