Re: z/series assembler...
The longevity is more attributable to the quality and constraint of IBM hardware design, both the original Gene Amdahl work and the thousands of engineers who could have easily fucked it up with each iteration.
I wonder how much BAL code is still running today in major systems, not just those small routines which required BAL to get the job done? Is ACP still booking flights?
The OS's are now coded for the most part in a thin PL/1 (SPL?, too many years) and when I say now I mean since the late 1970's, but lots of bare metal code, interrupt handlers, device and channel drivers were still in BAL even after the recode.
Anyway I'm out of here,