alt Hacker NewsNot only the System/390. Its also IBM i, AIX, and for many protocols the network byte order. AFAIK the binary data in JPG (1) and Java Class [2] files a re big endian. And if you write down a hexadecimal number as 0x12345678 you are writing big-endian.
(1) for JPG for embedded TIFF metadata which can have both.
[2] https://docs.oracle.com/javase/specs/jvms/se7/html/jvms-4.ht...
The endianness of file formats and handwriting is irrelevant when it comes to deciding whether your code should support running on big-endian CPUs.
The only question that matters: Do your customers / users want to run it on big-endian hardware? And for 99% of programmers, the answer is no, because their customers have never knowingly been in the same room as a big-endian CPU.