>>44The idea is that the interpreter/compiler is the shell and fundamentally forms the operating system itself. In unix programs were meant to be compiled to machine code, read and write from their stdout,stderr,stdin, open files, and use system calls to request other misc services from the operating systems. Then shell scripts can call these programs, redirect their outputs into each other and things like that. In a lisp system, all services provided by the operating system are invoked though lisp. Programs are subroutines written in lisp. There are other projects with the aim of creating an operating system in this sort of language, and one advantage is that since it's garbage collection, it is not possible (or should not be possible) to refer to memory that was not provided to the program for use. So there doesn't need to be a hardware solution to keeping memory allocated to a process private to that process. But these languages are currently slower than languages like C and hand coded asm. Also in order to communicate with the underlying architecture, there needs to be some asm at some point.
>>46unix style permissions are sufficient as long as it's acceptable for physical access to the machine to compromise the system. Otherwise encrypting each user's home directory with a key provided by the user will preserve privacy in the face of physical access when the user is not active. However the super user can still know the key of the user when the user creates their account, and the one with physical access to the machine can still discover the key when the user logs in or is active. The old unix system was based around the model of multiple users logging into a possibly remote machine, and in this case encryption doesn't help very much for personal use, since you don't physically own the machine.