An anecdote about backward compatibility
blog.plover.com
blog.plover.com
My old man started his tech work on hot rods, then mechanical typewriters, calculators, eventually continuing into mainframe electronics and nearly followed all the transitions up to today’s AI.
The number of times I’ve scratched my head at a problem and he had a clear understanding of where the logic broke… based on a historical decision that could not physically be undone.
They come from Lapack, the standard linear algebra foundation library, which is written in Fortran 77. That library was first written in 1992, when the Fortran 90 standard was still new and not supported everywhere, so they stuck with the earlier version. Lapack has become the standard library for dense non-parallel linear algebra; it is still maintained and updated, but the basic math algorithms haven't changed much, so there was no need to replace it entirely. Today there are also processor-specific libraries like MKL or Apple Accelerate, but they still all follow the same Lapack API.
When Fortran-77 was standardized, they decided to keep function names at most 6 letter long, to "ensure portability". I.e., they wanted to support certain compilers and architectures that were already considered old in 1977.
TL;DR: if you can't read easily those flame graphs today, it's because of backward compatibility with certain mainframes that probably date back to the late 1960s.
https://en.wikipedia.org/wiki/36-bit_computing#History
EDIT: I had thought 10 digits of precision were required for certain calculations, but the WP article points out that they may have just corresponded to the operators having had 10 digits on 2 hands, in which case we're being backwards compatible with Hox genes, specifically Hoxd, and tetrapod pentadactyly is backwards compatible to hundreds of millions of years:
Fortran predates this and was a different lineage than IBM, but not how six char symbols were a request
> The MACRO language had been used on the TX-0 for some three years previous to the writing of MIDAS. Hence, MIDAS incorporates most, of the features which have been requested by users of MACRO, such as more flexible macro Instructions, six character symbols and relocation.
Note that when porting b to the pdp-11, which was ascii vs the earlier FIODEC/flexowriter 6 bit paper tapes is why c case statements fall through, they used it to allow lower case commands in ed as an example.
Flexowriters are 1940s iirc, and TX-0 through the early pdps were octal so it makes sense to grow in multiples of the 3.3 bit lines of paper tape
[0] http://bitsavers.org/pdf/mit/rle_pdp1/memos/PDP-1_MIDAS.pdf
IIRC that wasn’t droop until the renaissance when they read Archimedes attempt to calculate the number of grains of sand needed to fill the universe with grains of sand, he used decimal and they asserted it was superior.
So you can consider decimal as tech debt:)
Never thought about why that might be other than "yeah, memory is expensive".
Most of the time, it's something you could never conceivably figure out without having been there at the time. But after 10 seconds on the phone or a brief email from someone who was, it makes complete sense.
I'd probably consider using IBM if it wasn't so goddamn weird and expensive. I suppose all that backward compatibility does have its downsides. Windows feels a bit weird in some places too, but at the same time it didn't start out life as a typewriter.
Windows 11 still has some dialogs that haven't been touched (and they can't ever be, in order to prevent backward compatibility breakage) since Windows 3.1: https://www.windowsonwindows.com/forum/viewtopic.php?t=44
The nerve takes a 15-foot detour down the long neck and loops under the aorta near the heart before it travels back up because evolution needed to stay backwards compatible with previous iterations of protogiraffes as environmental selection pressure lengthened the neck.
Not one character, but two: Carriage Return and Line Feed. Literally the action of moving the printer back to the beginning of the line and then the action of making the sheet of paper go "up" by one line.