starting process - Unix

This is a discussion on starting process - Unix ; After booting, GRUB gives control to the starting process.(my teacher told me). the starting process may be init or shed. it depends upon implementation. I know shed is the scheduler in unix. What does this init do ????...

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  1. starting process

    After booting, GRUB gives control to the starting process.(my teacher
    told me).

    the starting process may be init or shed. it depends upon
    implementation.

    I know shed is the scheduler in unix. What does this init do ????



  2. Re: starting process

    On Wed, 17 Sep 2008 11:57:54 -0700, asit wrote:

    > After booting, GRUB gives control to the starting process.(my teacher
    > told me).
    >
    > the starting process may be init or shed. it depends upon
    > implementation.
    >
    > I know shed is the scheduler in unix. What does this init do ????


    Nothing. Everything.
    .... well, basically just fork() and wait().

    HTH,
    AvK

  3. Re: starting process

    In <822e4327-8067-4ac7-b12d-36b15fd66a6b@c22g2000prc.googlegroups.com> asit writes:

    > What does this init do ????


    As with any other unix program, you can use the "man" facility to learn
    more about it.

    man init

    --
    John Gordon A is for Amy, who fell down the stairs
    gordon@panix.com B is for Basil, assaulted by bears
    -- Edward Gorey, "The Gashlycrumb Tinies"


  4. Re: starting process

    On Sep 17, 11:57*pm, asit wrote:
    > After booting, GRUB gives control to the starting process.(my teacher
    > told me).


    OMG ...

    GRUB is the bootloader which gives control to an operating system, and
    not to any "process".
    The Operating System boots and then in the final stage of booting
    gives control to init.

    >
    > the starting process may be init or shed. it depends upon
    > implementation.
    >
    > I know shed is the scheduler in unix. What does this init do ????


    Init is the first process that the OS spawns. It is the parent of all
    the processes.

    AFAIK, shed is a hex editor.
    http://sourceforge.net/projects/shed




  5. Re: starting process

    But if i execute ps -e, shed has pid 0 and init has 1 .

    so shed gets executed first, then init.

  6. Re: starting process

    On Sep 18, 1:19*pm, asit wrote:
    > But if i execute ps -e, shed has pid 0 and init has 1 .
    >
    > so shed gets executed first, then init.


    It is the first process when the system starts.All the other process
    spawns from this .

  7. Re: starting process

    >But if i execute ps -e, shed has pid 0 and init has 1 .

    I thought 'shed' was a container process in the back yard for
    lawn mowers and garden tools when they are idle.

    >so shed gets executed first, then init.


    Are you sure this isn't spelled 'sched'?

    My system has a process 'schedcpu' which is process 47.


  8. Re: starting process

    On Wed, 17 Sep 2008 11:57:54 -0700, asit wrote:

    > After booting, GRUB gives control to the starting process.(my teacher
    > told me).


    You will learn faster and better if you boot a unix-type system yourself.

    >
    > the starting process may be init or shed. it depends upon
    > implementation.
    >
    > I know shed is the scheduler in unix. What does this init do ????


    Init, processes a file, commonly /etc/inittab and then spawns processes
    as needed. Using this file, it will know what to do. As init reads this
    file, it will find a line that tells it what the default runlevel is.
    Each runlevel has different scripts, which control how your system
    starts. These script may be in a folder /etc/init.d Often init will
    spawn tty's so you have access to a command prompt. It will also start
    your graphical interface if it is set up to do so. All other processes
    are started by init. Commands can be sent to init with telinit. You can
    tell init to jump into a different runlevel. What processes are started
    or stopped in different runlevels is dependent on your system, and set in
    the file /etc/inittab and or folders in /etc/init.d or /etc/rc.d.

    By default, the kernel will start init as the first process.
    The kernel can be told to start another program instead of init. This
    way you can bypass the init process, and jump straight into a shell.
    Using grub to start linux this is done by appending init=/bin/program to
    your kernel boot line. I don't know what shed is, but if you read your
    grub boot menu, you may see something like this on the kernel line
    init=/bin/shed

    Perhaps your shed program does some bookkeeping and then spawns init for
    you. If you post you grub menu list, and tell us what unix system you
    are on, we can better help you understand what init does on your system.

    There are different methods used by different OS's. Two common methods
    are system-v style and bsd style.

    A beginners introduction..... http://en.wikipedia.org/wiki/Init

    Sorry if I am a bit confusing, but my consulting fees are very low....

    stonerfish


  9. Re: starting process


    "jellybean stonerfish" wrote in message
    news:0jvAk.628$be.526@nlpi061.nbdc.sbc.com...
    > On Wed, 17 Sep 2008 11:57:54 -0700, asit wrote:
    >
    >> After booting, GRUB gives control to the starting process.(my teacher
    >> told me).

    >
    > You will learn faster and better if you boot a unix-type system yourself.
    >
    >>
    >> the starting process may be init or shed. it depends upon
    >> implementation.
    >>
    >> I know shed is the scheduler in unix. What does this init do ????

    >
    > Init, processes a file, commonly /etc/inittab and then spawns processes
    > as needed. Using this file, it will know what to do. As init reads this
    > file, it will find a line that tells it what the default runlevel is.
    > Each runlevel has different scripts, which control how your system
    > starts. These script may be in a folder /etc/init.d Often init will
    > spawn tty's so you have access to a command prompt. It will also start
    > your graphical interface if it is set up to do so. All other processes
    > are started by init. Commands can be sent to init with telinit. You can
    > tell init to jump into a different runlevel. What processes are started
    > or stopped in different runlevels is dependent on your system, and set in
    > the file /etc/inittab and or folders in /etc/init.d or /etc/rc.d.
    >

    Runlevels on my linux 0 for halt. 6 for reboot 5 for X which I remove from
    my system's init table because I don't run X. 1 for normal running. Instead
    of calling halt I always use init 6 for reboot and init 0 to halt. Try calls
    init yourself.. I think it's probably close to System V and BSD.

    Bill



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