[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: mountkernfs, mountvirtfs, and devpts.sh

In article <[🔎] 20040427211738.GA5351@hank.org>,
Bill Moseley  <moseley@hank.org> wrote:
>I'm not using tmpfs for anything that I know of.  That's why I didn't
>enable it on my last kernel build.  Do systems expect that tmpfs will
>be available?  I see I've got it enabled on other machines but /dev/shm
>is empty.  Why use the RAM if it's not needed.

It's not using any RAM if you don't use it. As far as I understand
it, the kernel uses an internal mount of tmpfs for SysV shared
memory support, and when tmpfs is enabled you can use an
external mount (on /dev/shm) for POSIX shared memory support,
and you can also use that as a real temp fs.

>[BTW -- can tmpfs get swapped to disk?  That would seem to defeat the
>purpose, I guess.]

Tmpfs pages can get swapped, yes.

>I guess I was trying to understand devpts by asking a question.  I'm not
>entirely clear what devpts is or does and why it's needed and when it's
>not.  Does it only provide the ALT+Fn virtual terminal switching or is


>is needed for ssh'ing into the box?


>What would happen if it didn't get

Depends on the application. If it supports BSD style pty's and you
have those in /dev you won't much notice.


Reply to: