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4GB VM for 32 bit processes - UNIX Programming

Loic Domaigne wrote:  [/ref] >  > > clever... >  > > Yes... actually, I didn't thought about it. But I believe, you can > automatically find out in which direction does the stack grow. > > Indeed, ISTM that 'comparing' the value of the address of > argc and argv (for instance) should be enough... >  > > I see a problem here!! IIRC, the memory layout of HP-UX is quite different > from the other Un*x I saw... > > You must understand that this program find the first invalid address > 'after' the program's stack. It doesn't mean ...

  1. #21

    Default Re: 4GB VM for 32 bit processes

    Loic Domaigne wrote:
     [/ref]

    >
    > clever...

    >
    > Yes... actually, I didn't thought about it. But I believe, you can
    > automatically find out in which direction does the stack grow.
    >
    > Indeed, ISTM that 'comparing' the value of the address of
    > argc and argv (for instance) should be enough...

    >
    > I see a problem here!! IIRC, the memory layout of HP-UX is quite different
    > from the other Un*x I saw...
    >
    > You must understand that this program find the first invalid address
    > 'after' the program's stack. It doesn't mean necessarily that it is the
    > start address of the kernel (it happens to be the case on Linux/IA, but
    > Linux/IA is a PARTICULAR implementation).
    >
    > Again, the 2 strong assumptions of my solution are:
    >
    > - the VM is divided into 2 contiguous parts: one for the user space, and one
    > for the kernel space.
    >
    > - the kernel starts right 'after' the process stack.
    >
    > If one if this assumption doesn't hold for any reason, the address that
    > you are obtaining is wrong.
    >
    > I would definitively check the validity of such assumptions on the
    > corresponding NG for the Unix implementations you are interested
    > (e.g. comp.unix.solaris for Solaris, or comp.sys.hpux for HP-UX).
    >
    > Good luck!
    > Loic.
    > --
    > Article posté via l'accès Usenet http://www.mes-news.com
    > Accès par Nnrp ou Web[/ref]

    Thanks Loic for all your help.
    Please let me know if you find memory layout of Solaris and HPUX systems.
    Manish

    Manish Guest

  2. #22

    Default Re: 4GB VM for 32 bit processes

    Manish Baronia wrote:
     
    > > 
    > >
    > > clever...
    > > 
    > >
    > > Yes... actually, I didn't thought about it. But I believe, you can
    > > automatically find out in which direction does the stack grow.
    > >
    > > Indeed, ISTM that 'comparing' the value of the address of
    > > argc and argv (for instance) should be enough...
    > > 
    > >
    > > I see a problem here!! IIRC, the memory layout of HP-UX is quite different
    > > from the other Un*x I saw...
    > >
    > > You must understand that this program find the first invalid address
    > > 'after' the program's stack. It doesn't mean necessarily that it is the
    > > start address of the kernel (it happens to be the case on Linux/IA, but
    > > Linux/IA is a PARTICULAR implementation).
    > >
    > > Again, the 2 strong assumptions of my solution are:
    > >
    > > - the VM is divided into 2 contiguous parts: one for the user space, and one
    > > for the kernel space.
    > >
    > > - the kernel starts right 'after' the process stack.
    > >
    > > If one if this assumption doesn't hold for any reason, the address that
    > > you are obtaining is wrong.
    > >
    > > I would definitively check the validity of such assumptions on the
    > > corresponding NG for the Unix implementations you are interested
    > > (e.g. comp.unix.solaris for Solaris, or comp.sys.hpux for HP-UX).
    > >
    > > Good luck!
    > > Loic.
    > > --
    > > Article posté via l'accès Usenet http://www.mes-news.com
    > > Accès par Nnrp ou Web[/ref]
    >
    > Thanks Loic for all your help.
    > Please let me know if you find memory layout of Solaris and HPUX systems.
    > Manish[/ref]

    Hi Loic,
    Please let me know if you could find any information on memory layout on
    Linux, HP.
    Thanks,
    Manish

    Manish Guest

  3. #23

    Default Re: 4GB VM for 32 bit processes

    Hi Manish,
     [/ref]
    >
    > Please let me know if you could find any information on memory layout
    > on Linux, HP.[/ref]

    I did some search on the net concerning HP-UX, but I couldn't find any
    interesting information...

    I stuck right now at the hospital, so it´s difficult for me do any
    search right now. Please, could you do that search yourself? At best,
    post on comp.unix.solaris resp. comp.sys.hpux!

    TIA,
    Loic.

    --
    Article posté via l'accès Usenet http://www.mes-news.com
    Accès par Nnrp ou Web
    Loic Guest

  4. #24

    Default Re: 4GB VM for 32 bit processes

    Loic Domaigne wrote:
     
    > >
    > > Please let me know if you could find any information on memory layout
    > > on Linux, HP.[/ref]
    >
    > I did some search on the net concerning HP-UX, but I couldn't find any
    > interesting information...
    >
    > I stuck right now at the hospital, so it´s difficult for me do any
    > search right now. Please, could you do that search yourself? At best,
    > post on comp.unix.solaris resp. comp.sys.hpux!
    >
    > TIA,
    > Loic.
    >
    > --
    > Article posté via l'accès Usenet http://www.mes-news.com
    > Accès par Nnrp ou Web[/ref]

    Hi Loic,
    Oh, Hope, things are fine with you. I am really sorry to bother you.
    Yes, I will do post at the newsgroup mentioned by you.
    Thanks,
    Manish


    Manish Guest

  5. #25

    Default Re: 4GB VM for 32 bit processes

    On Tue, 09 Sep 2003 12:20:18 +0530
    Manish Baronia <com> wrote:
     
    > >
    > > Thanks Loic for all your help.
    > > Please let me know if you find memory layout of Solaris and HPUX
    > > systems. Manish[/ref]
    >
    > Hi Loic,
    > Please let me know if you could find any information on memory
    > layout on
    > Linux, HP.[/ref]
    I think I posted this earlier.
    HP-UX processes are given 4 memory chunks. I don't have the details at
    my fingertips right now, but the way they line up for PA-RISC 32 bit is:
    1. 1GB text
    2. 1GB data
    3. 1GB shared memory
    4. 1GB shared libraries.

    64 bit implementations are significantly larger.

    Additionally, on HP-UX, the stack grows upwards where on most other
    systems the stack grows downwards.

    (BTW: This memory model is changed on HP-UX(Itanium).

    --
    Jerry Feldman <gaf-nospam-at-blu.org>
    Boston Linux and Unix user group
    http://www.blu.org PGP key id:C5061EA9
    PGP Key fingerprint:053C 73EC 3AC1 5C44 3E14 9245 FB00 3ED5 C506 1EA9
    Jerry Guest

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