4 ms·

Hah, anecdote incoming, but 100x times a resource usage is probably accurate. Given, 100x of a human hair is still just a minuscule grain of sand, but that’s th

Hah, anecdote incoming, but 100x times a resource usage is probably accurate. Given, 100x of a human hair is still just a minuscule grain of sand, but that’s the scale margins Mainframe operators work in. As one grey beard said it to me: Java is loosely typed and dynamic compared to colbol/db2/pl-sql. He was particularly annoyed that the smallest numerical type a ‘byte’ in Java was quote: “A waste of bits” and that Java was full of “useless bounds checking” both of which were causing “performance regressions”. The way mainframe programs are written is: the entire thing is statically typed.

PaulHoule 1y ago
I knew mainframe programmers were writing a lot of assembly in the 1980s and they probably still are.
- BugheadTorpeda6 1y ago
  It's one of the last platforms that people still write a lot of hand written assembly for. Part of this is down to the assembler being very ergonomic and there being a very capable macro system available with macros provided for most system services. Part of it is due to the OS predating C becoming popular, so there are no headers files (just assembler macros) for many older system services (you can thunk them into C compatible calls, but it's sometimes more of a headache than just writing in assembler). Definitely C is becoming more popular lately on the platform, but you will still find a lot of people programming in assembler for a living in 2025. Its probably the only subfield of programming that uses handwritten assembly in that way outside of embedded systems.
thechao 1y ago
When I was being taught assembly at Intel, one of the graybeards told me that the greatest waste of an integer was to use it for a "bare" add, when it was a perfectly acceptable 64-wide vector AND. To belabor the the point: he used ADD for the "unusual set of XORs, ANDs, and other funky operations it provided across lanes". Odd dude.
- uticus 1y ago
  > ...it was a perfectly acceptable 64-wide vector AND. sounds like "don't try to out-optimize the compiler."
  - thechao 1y ago
    In 2025, for sure. In 2009 ... maybe? Of course, he had become set in his ways in the 80s and 90s.
- dragontamer 1y ago
  Reverse engineering the mindset.... In the 90s, a cryptography paper was published that more quickly brute forced DES (standard encryption algorithm back then) using SIMD across 64-bit registers on a DEC Alpha. There is also the 80s Connection Machine which was a 1-bit SIMD x 4096-lane supercomputer. --------------- It sounds like this guy read a few 80s or 90s papers and then got stuck in that unusual style of programming. But there were famous programs back then that worked off of 1-bit SIMD x 64 lanes or x4096 lanes. By the 00s, computers have already moved on to new patterns (and this obscure methodology was never mainstream). Still, I can imagine that if a student read a specific set of papers in those decades... This kind of mindset would get stuck.
  - formerly_proven 1y ago
    That's bit-slicing (not the hardware technique).
rbanffy 1y ago
> the entire thing is statically typed. Not always, but they do have excellent performance analysis and will do what they can to avoid slow code in the hottest paths.

PaulHoule 1y ago

I knew mainframe programmers were writing a lot of assembly in the 1980s and they probably still are.

BugheadTorpeda6 1y ago
It's one of the last platforms that people still write a lot of hand written assembly for. Part of this is down to the assembler being very ergonomic and there being a very capable macro system available with macros provided for most system services. Part of it is due to the OS predating C becoming popular, so there are no headers files (just assembler macros) for many older system services (you can thunk them into C compatible calls, but it's sometimes more of a headache than just writing in assembler). Definitely C is becoming more popular lately on the platform, but you will still find a lot of people programming in assembler for a living in 2025. Its probably the only subfield of programming that uses handwritten assembly in that way outside of embedded systems.

thechao 1y ago

When I was being taught assembly at Intel, one of the graybeards told me that the greatest waste of an integer was to use it for a "bare" add, when it was a perfectly acceptable 64-wide vector AND. To belabor the the point: he used ADD for the "unusual set of XORs, ANDs, and other funky operations it provided across lanes". Odd dude.

uticus 1y ago
> ...it was a perfectly acceptable 64-wide vector AND. sounds like "don't try to out-optimize the compiler."
- thechao 1y ago
  In 2025, for sure. In 2009 ... maybe? Of course, he had become set in his ways in the 80s and 90s.
dragontamer 1y ago
Reverse engineering the mindset.... In the 90s, a cryptography paper was published that more quickly brute forced DES (standard encryption algorithm back then) using SIMD across 64-bit registers on a DEC Alpha. There is also the 80s Connection Machine which was a 1-bit SIMD x 4096-lane supercomputer. --------------- It sounds like this guy read a few 80s or 90s papers and then got stuck in that unusual style of programming. But there were famous programs back then that worked off of 1-bit SIMD x 64 lanes or x4096 lanes. By the 00s, computers have already moved on to new patterns (and this obscure methodology was never mainstream). Still, I can imagine that if a student read a specific set of papers in those decades... This kind of mindset would get stuck.
- formerly_proven 1y ago
  That's bit-slicing (not the hardware technique).

rbanffy 1y ago

> the entire thing is statically typed. Not always, but they do have excellent performance analysis and will do what they can to avoid slow code in the hottest paths.