/tech/ - Technology★

>why are 32-bit things often incompatible with 64-bit operating systems

But they aren't?

>>1003782

>But they aren't?

Hmm, perhaps I shouldn't have said "often" but for example, with Haiku (the OS), the 32-bit BeOS programs are incompatible with the 64-bit version of the OS

>>1003783

>why do two different OSes not have drop in compatibility with each other

really made me think

usually (but not always), 64-bit OSes will support 32-bit programs, but never the other way around

a CPU will have a bus width, so if a CPU is 32-bit, that means it can handle instructions with a size of 32 1s and 0s

a 64-bit CPU can still run 32-bit instructions because it's less than its maximum bus width

however, I have also heard that 64-bit OSes also lose support for 16-bit software

a 32-bit OS or CPU can only address 4GB of RAM because 2^32 is approximately 4.3 billion (4GB)

but for the best compatibility, you'd want the CPU, OS, and programs to all be the same

>>1003783

The instructions are different. To run 32bit code in a 64bit CPU you run it as 32bit. No big surprise there. Thing is since you're in 32bit mode you must use 32bit libraries, Haiku perhaps doesn't provide both.

>>1003779 (OP)

It depends on the OS. For example, I can't run 16-bit Windows software via Wine because my kernel is compiled without the 16-bit support.

>>1003779 (OP)

32bit has a different ABI. Especially for syscalls.

>>1003779 (OP)

>using the term "n00bie"

>question that doesn't deserve it's own thread

BEGONE YOU UNDERAGE NIGGERFAGGOT