I assume we arrived at the conclusion that UNIX98_PTYS enables devpts, which
is the current standard of kernel support for virtual terminals?
It is interesting to note that in every situation except one, UNIX98_PTYS=y
is a default.
After experimenting, it turns out that even setting CONFIG_EMBEDDED does not
turn off UNIX98_PTYS=y. The only way to disable it is to set CONFIG_LEGACY_PTYS=y.
Obviously, there has to be some some setting for virtual terminals and it
seems that the kernel writers have determined that the legacy support is
for embedded systems. As you previously quoted:
Code:
All modern Linux systems use the Unix98 ptys. Say Y unless
you're on an embedded system and want to conserve memory.
This implies that the devpts system is a memory resident service:
legacy support creates device nodes on the main file system.
I'm not sure this makes any difference to an embedded system assuming that
it must contain all of its code in an imbedded chip. Apparently, the memory
requirements of devpts occupies more space than a single legacy console.
I'm not sure this is correct, but it seems to make some sense. It would
be nice if this was explained in the help section of menuconfig.