[alerighi]

Except than later we returned to a sort-of segmented memory. That is of course paging, our programs allocates pages of memory that are a fixed size (4096 bytes) and are arranged in memory or in swap space how the OS decides.

We just have the illusion of a "flat" memory model, but it's not really flat, the CPU and the operating system does an important job in translating our flat memory model in something that is not flat at all. All that address translation work could have been avoided if we accepted to not have a flat memory model and be aware that our memory is divided in pages.

Basically we are doing in hardware the job of managing a non flat memory space that the programmer, or well, the compiler (or these days you would say the AI agent) could probably to better because it knows how to allocate things to avoid being them on page boundaries, and all of this to give the illusion to the programmer that it's working with a flat memory (except when it does something wrong and gets a segmentation fault, that, as the name suggests, is an hint that at the end the memory is not really flat).

[bluGill]

In turn though, the thinking needed to handle non-flat memory is a complexity that most programmers cannot handle - and even those who could probably should spend their brain power on the complex parts of their program not managing memory. Best to leave that hard part to a few experts instead of make everyone understand it.

The above is very similar to the argument that you should use a garbage collected langauge.

[wang_li]

Paging is not part of the CPU architecture. On CPUs of the time the MMU that brought paging to the party often was a completely separate peripheral that the CPU interacted with to gate access to RAM. By contrast segments are an integral part of the CPU instruction set and your code either has to limit itself to 64KB or your application had to be aware of and include logic to manage segments.

As an aside, the memory model is flat, it's just not physically linear when implementing virtual memory addressing.