Two Kinds of Object Libraries:

• static - linked into the executable image (ex libc.a)
• dynamic shared objects (DSO) -The object modules are bound into the executable at runtime (ex libc.so)

Advantages of DSOs:

• Possibly smaller process memory utilization
  A shared library module is bound into system memory when the first
  running program references it. If any subsequent running program references
  it, that reference is mapped to this first copy.
  
  
• Easier to update
  Installing an updated dynamic library on a system immediately
  affects all the applications that use it without requiring relinking of the executable.
  
  
• Smaller executable files
  Deferring binding of the library routines until execution time means that the size of the executable
  file is less than the equivalent executable calling a static version of the library; the executable file
  does not contain the binaries for the library routines.
  
  

Disadvantages of DSOs:

• Possibly increased overhead
  Additional processor time is needed to load and link-edit the library routines during runtime.
  Also, the library's position-independent coding may execute more slowly than the relocatable
  coding in a static library.
  
  
• Less Portable Code
  Shared libraries must be ported along with the executable if they are not available on the system to
  which code is being ported.
  
  
• Slight Performance Impact
  Usually around 5%.