is shared by both processes. The total memory requirement for these two processes running simultaneously is 896Kb (256Kb + 128Kb + 512Kb).
Figure 7 Two Processes Sharing libc
Compare this with the memory requirements if prog1 and prog2 are linked with the archive version of libc. As shown in Figure 8 (page 93), 1428Kb of memory is required (768Kb + 640Kb). The numbers in this example are made up, but it is true in general that shared libraries reduce memory requirements.
Figure 8 Two Processes with Their Own Copies of libc
Example Program Comparing Shared and Archive Libraries 93