interview question how does application connects to device

[Mandeep Sandhu]

> Let me simplify the question.

I'll attempt to answer your questions...for my own edification! :)

>
> 1) What are the FIVE classic system calls for interfacing with a
> character device.  (ie. If it did not exist in 1970, don't list it).

open/close/read/write/seek?...and the infamous ioctl.
>
> 2) Which of the 5 is still heavily used in the kernel but is
> discouraged for new drivers being accepted into the linux kernel?

I'm guessing this is ioctl's...because now the preferred way to
communicate/give commands to a device is via sysfs?
>
> 3) Name at least 3 alternatives that have been routinely used for
> out-of-band communication in the Linux kernel since 2000.

ioctl's, profs/sysfs, netlink sockets maybe?

Thanks,
-mandeep