Re: [Re: Process creating]

Re: [Re: Process creating]

[Blesson Paul]

Hi Android
                        IPC is my last resort. The reason is that, my present
project is to convert a present software to run in beowlf. I am using Mosix
which enables me to parralize the software through forking. The present
software is highly data oriented and highly  complicated. If all the processes
manipulates the data in the same memory area, I need not look into IPC.
Moreover there is less need for synchronisation since the data are readonly.
The memory mapping in  different systems are done by Mosix. It somehow enables
me to use all the memory in different systems as if they are of single one    
      
                             by
                                   Blesson
 
Android <android@abac.com> wrote:

>1  If I point  to a address 0x434343 in P1 and  P2, will it point to the
>same memory area.
>2  If not, I need two processes to use same process area, how to do that
>3  Will linux kernel support threading
>                             Actually I first thought about shared memory.
But
>for my application, I need huge memory area upto 50MB or more. So 50MB of
>shared memory is no good. So I looking for any other alternatives
>
>                        by
>                                   Blesson

1: P1 and P2 have different physical areas of memory. This is how 
protection works.

2: Why do they need to share the same memory? You can have your second
process
communicate with your first process through IPC.

3: Linux supports threading if you include the thread library, and use the 
appropriate
threading process calls.

Another thing you can do is have a common space on the hard drive. It's not 
as fast as RAM,
but it's one solution.

                                                        -- Ted

Re: [Re: Process creating]

[Jan Hudec]

On Wed, Jun 27, 2001 at 12:35:13AM -0600, Blesson Paul wrote:
> 1: P1 and P2 have different physical areas of memory. This is how 
> protection works.
> 
> 2: Why do they need to share the same memory? You can have your second
> process
> communicate with your first process through IPC.
> 
> 3: Linux supports threading if you include the thread library, and use the 
> appropriate
> threading process calls.
> 
> Another thing you can do is have a common space on the hard drive. It's not 
> as fast as RAM,
> but it's one solution.

As to 1 (and 3), if you clone the processes (using the __clone - advanced
version of fork), you can specify what the processes should share. Including
memory. Thus you can also have threads (that share everything but stack) even
without a thread library (libpthread actualy does just that, but it has some
conveniece stuff like locks).

As of 2, avoid using ipc, especialy the sysv one - it's rather kind
of crap (IMHO).

-------------------------------------------------------------------------------
						 Jan 'Bulb' Hudec <bulb@ucw.cz>