Well a VM is meant to provide a machine agnostic environment.
An os does the same, with the quirk that its processor specific.
If youre writing Posix C, you shouldn't need to care what that software is running on, as long as its Posix. same goes for a Java or Smalltalk VM.
I suppose some things get interesting, when you start thinking in terms of languages. If you want to write to a serial port, is that an OS thing, or is that a library? Same for the file system. Is MSDOS an OS, or a library?
if you want to go ultra minimalist an OS is just locks and privileges. but I don't think anyone would class that as an OS.
The only satisfying answer for me, is the OS as a collection of services. Those services could be in the form of a programming language, but as Mr Kay points out, some bits don't fit in the programming language model.
This then raises the question, of how far you can take the model. 'everything as a file' does quite well, despite not applying to everything
An os does the same, with the quirk that its processor specific.
If youre writing Posix C, you shouldn't need to care what that software is running on, as long as its Posix. same goes for a Java or Smalltalk VM.
I suppose some things get interesting, when you start thinking in terms of languages. If you want to write to a serial port, is that an OS thing, or is that a library? Same for the file system. Is MSDOS an OS, or a library?
if you want to go ultra minimalist an OS is just locks and privileges. but I don't think anyone would class that as an OS.
The only satisfying answer for me, is the OS as a collection of services. Those services could be in the form of a programming language, but as Mr Kay points out, some bits don't fit in the programming language model.
This then raises the question, of how far you can take the model. 'everything as a file' does quite well, despite not applying to everything