[simscitizen]

There's already a popular OS that disables overcommit by default (Windows). The problem with this is that disallowing overcommit (especially with software that doesn't expect that) can mean you don't get anywhere close to actually using all the RAM that's installed on your system.

[masklinn]

Windows also splits memory allocations between allocating the virtual space and committing real memory. So you can allocate a large VM when you need one and use piecemeal commits within that space.

POSIX not so much.

[machinationu]

I am regularly getting close to 100% RAM usage on Windows doing data processing in Python/numpy