all about shared memory


 
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Operating Systems Linux all about shared memory
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Old 02-28-2006
Question all about shared memory

Hi all Smilie ,
I am new to unix.I have been asked to implement shared memory in user's mode.What does this mean?What is the difference it makes in kernel mode and in users mode?What are the advantages of this impemenation(user's mode)?

And also i would like to know why exactly shared memory called the fastest IPC mechanism?
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IPCMK(1)							   User Commands							  IPCMK(1)

NAME
ipcmk - make various IPC resources SYNOPSIS
ipcmk [options] DESCRIPTION
ipcmk allows you to create shared memory segments, message queues, and semaphore arrays. OPTIONS
Resources can be specified with these options: -M, --shmem size Create a shared memory segment of size bytes. The size argument may be followed by the multiplicative suffixes KiB (=1024), MiB (=1024*1024), and so on for GiB, etc. (the "iB" is optional, e.g., "K" has the same meaning as "KiB") or the suffixes KB (=1000), MB (=1000*1000), and so on for GB, etc. -Q, --queue Create a message queue. -S, --semaphore number Create a semaphore array with number of elements. Other options are: -p, --mode mode Access permissions for the resource. Default is 0644. -V, --version Display version information and exit. -h, --help Display help text and exit. SEE ALSO
ipcrm(1), ipcs(1) AUTHOR
Hayden A. James <hayden.james@gmail.com> AVAILABILITY
The ipcmk command is part of the util-linux package and is available from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils /util-linux/>. util-linux July 2014 IPCMK(1)

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