Difference between 'device' and 'options'

Chris Zhu

New Member


Messages: 2

According to config(5) manual, 'devices' are defined in sys/conf/files and 'options' are defined in sys/conf/options, but it seems to me both keywords would make the feature built into kernel, so I am not sure which one I should use in a kernel config file? Can anyone help explain the exact difference between them? Thanks!
 

mjollnir

Daemon

Reaction score: 750
Messages: 1,197

According to config(5) manual, 'devices' are defined in sys/conf/files and 'options' are defined in sys/conf/options, but it seems to me both keywords would make the feature built into kernel, so I am not sure which one I should use in a kernel config file? Can anyone help explain the exact difference between them? Thanks!
  • device & devices includes the driver for that device into the kernel.
    These do not necessarily have to be physical devices, they can be virtual devices like e.g. a wlan(4) or gif(4) network interface.
  • option(s) enables a specific feature in the kernel.
    some devices have additional options, e.g. the vga(4) driver has the option VESA
E.g.: there is no driver for the scheduler. Either the kernel has the option SCHED_ULE or SCHED_4BSD - there's no default & FreeBSD kernel is not Mach microkernel, i.e. you can not change the scheduler at runtime.
EDIT: Resources for Newbies 2nd EDIT: I'd suggest you stick to the precompiled GENERIC kernel and explore & learn FreeBSD for a while. Once you start to feel comfortable (you play with the system and not the other way around ;)), you can start to build your own kernel & world.
 
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