[lug] booting and kernel compiling (was dumpdates)

Wayde Allen wallen at boulder.nist.gov
Wed Aug 16 10:19:20 MDT 2000

On Tue, 15 Aug 2000, John Starkey wrote:

> > The kernel is really just a
> > standardized interface to the system hardware.  
> Ok, to be philosophical. What you're saying is that the kernel really
> doesn't have anything to do with keeping the insides going, actively. I
> guess that makes sense. Cron though, it get's executed something
> what would that be? I assume it's fed from the internal clock (not the
> bios right, bios is only the initial boot mechanism)?

I'm not sure I follow.  The kernel is your interface to the hardware.  If
as you say it has nothing to do with keeping the insides going I wouldn't
need to buy a computer.

Cron is a computer program.  It isn't a part of the kernel.  Yes, it uses
the system clock.  You are correct that the bios is just the initial boot
mechanism.  Once Linux starts the bios is no longer relevant.

> > It doesn't have a reason
> > or desire to call the mv command.  That is where you come into the
> > picture.  You were the one who tried to invoke that command.  The path is
> > part of the shell environment that you interact with.
> The mv command doesn't even use the kernel then. Pass any arguments??

Huh ... ?  Of course the move command uses the kernel.  Any program
running on the system uses the kernel since the kernel is what talks to
the hardware.  If it didn't use the kernel it wouldn't be running on the
system hardware and you wouldn't need a computer!

The kernel basically provides a standard software interface to the
hardware.  For instance, in Unix everything is treated as a file.  If you
go to /dev for instance you will find your disks listed as /dev/hd? or
/dev/sd?.  To read and right to them you really just need to read and
write these files, the kernel handles all of the issues of finding and
retrieving the appropriate pieces of data on the drives.  The same thing
goes for reading the keyboard or writing to the screen etc..  The
advantage of this kind of abstraction is that if you change the underlying
hardware you only need to re-write the kernel to support the hardware
rather than every program on the system.

- Wayde
  (wallen at boulder.nist.gov)

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