Datasheet

Chapter 1: What is Ubuntu?

Figure 1-3: The Ubuntu System Monitor utility, showing the current memory usage.

A shared memory page allows multiple processes to read and write to the same shared

memory area. The kernel maintains and administers the shared memory areas, control-

ling which processes are allowed access to the shared area.

The special

ipcs command allows us to view the current shared memory pages on the

system. Here’s the output from a sample

ipcs command:

test@testbox:~$ ipcs -m

------ Shared Memory Segments --------

key shmid owner perms bytes nattch status

0x00000000 557056 test 600 393216 2 dest

0x00000000 589825 test 600 393216 2 dest

0x00000000 622594 test 600 393216 2 dest

0x00000000 655363 test 600 393216 2 dest

0x00000000 688132 test 600 393216 2 dest

0x00000000 720901 test 600 196608 2 dest

0x00000000 753670 test 600 393216 2 dest

0x00000000 1212423 test 600 393216 2 dest

0x00000000 819208 test 600 196608 2 dest

0x00000000 851977 test 600 393216 2 dest

0x00000000 1179658 test 600 393216 2 dest

0x00000000 1245195 test 600 196608 2 dest

0x00000000 1277964 test 600 16384 2 dest

0x00000000 1441805 test 600 393216 2 dest

test@testbox:~$

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