Postgres Process in Kernel Mode?

Hello,

I'm new in postgres SQL and I have some questions about the space where
postgres process run.

1-Can any body say me what libs use postgres for make system calls, for
example LIBC?

2-Can any body talk me if some postgres process can run in Linux kernel
space?

3- Some body knows if exist some projects that ports postgres process on
Linux kernel space.

I was read some source code of postgres, like,

Postgres.C and others.

I was found C instructions like Printf, that's prohibitive for Linux kernel
applications, for example in kernel mode we use printk.

I suppose that postgres are ported in a user space only. I'm Ok?

Thanks

Moises

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