In win95, everything had access to everything if it wanted. E.g. DLLs were mapped in a shared memory segment that was shared between all applications. Lots of 16 bit code was still running, and this did IPC basically by messing in some other program's memory. Backward compatibilitty required very thin walls between processes.
DOS TSR programs started before windows were still running. I had one that popped up a calculator in dos text mode, and if you pushed its hotkey in win95, it switched win95 back to text mode, paused win95, did its thing, then popped back in win95.
Only the very basics of protected mode and virtual memory where there, and a well-behaving program had a reasonable chance of staying in its own sandbox. But only because it wanted to. Seen from the CPU, you could argue EMM386 was more the actual OS than win95/win98.
None of this is meant to be negative. It was a solid step up from windows 3.x, and yet quite usable with 4MB RAM of which the first 1MB wanted a very different treatment.
DOS TSR programs started before windows were still running. I had one that popped up a calculator in dos text mode, and if you pushed its hotkey in win95, it switched win95 back to text mode, paused win95, did its thing, then popped back in win95.
Only the very basics of protected mode and virtual memory where there, and a well-behaving program had a reasonable chance of staying in its own sandbox. But only because it wanted to. Seen from the CPU, you could argue EMM386 was more the actual OS than win95/win98.
None of this is meant to be negative. It was a solid step up from windows 3.x, and yet quite usable with 4MB RAM of which the first 1MB wanted a very different treatment.