It probably saved a few bytes of memory or disk. A PDP11 had 64k of memory and had to be shared by multiple simultaneous users. A lot of the Unix tradeoffs ca

It probably saved a few bytes of memory or disk. A PDP11 had 64k of memory and had to be shared by multiple simultaneous users. A lot of the Unix tradeoffs can be traced back to limitations of 1970s hardware. Plus you weren't going to need more than one anyway, your program wasn't going to be big enough.