   Unix    Berkeley Software
Distributions (BSD).     Unix,  
  1981 ,  3BSD.       4BSD:

4.0BSD, 4.1BSD, 4.2BSD  4.3BSD.      Unix 
  ,     (demand paging)
   TCP/IP.     Unix  
 4.4BSD,   1993 ,    
  .    BSD  
  Darwin, Dragonfly BSD, FreeBSD, NetBSD  OpenBSD.

 1980-1990-   ,     -
,       Unix.  -
      AT&T    -
   ,  
  .     Tru64 
Digital, HP-UX  Hewlett Packard, AIX  IBM, DYNIX/ptx 
Sequent, IRIX  SGI, Solaris  Sun.

     Unix  -
     ,    -
,   Unix ,   .  
   Unix    . -,
  Unix :        -
         
 , Unix-      -
       . -,  -
  Unix     2.   
     ,     
  : open (), read (), write (), iocti ()  close (). --
,       Unix   
      Unix    -
      .

  Unix         -
   fork ().  ,   Unix -
          ,
,      ,   -
 ,      ,    , 
        .

 Unix    ,   -
, ,  ,    -
,   ,   ,  
TCP/IP.     Unix  -
   ,        Unix  
     .   Unix
    ,    
(    )   

, ,  ,      .    -
,   19 ( Unix),      .

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