magic number ( ).  ,    512 
    1-, 2-  4-     ,
    ( 3-  -
   DOS).   .   /usr/share/magic   man-
 magic (5).

main memory ( ).     (Random Access
Memory  RAM),   ; .   .  
     ,      -
.

major device number (  ). ,   ,
  ,    .  Is   -1 
  /dev       .

MAN.   (Metropolitan area network). ,    -
         , -
, .

masquerade ().       IP- 
      IP-.   
(iptables)   (sendmail).

MD5.   5 (Message Digest 5).  -.

MDA.    (Mail Delivery Agent).     
;      MUA. MDA       -
   .

mega- (-).     "-"    220,  
1048576.       ""  "". -
   .

menu (). ,       .
           GUI-
,        .   
 ,   ,   ,   
 ,       -
.   ,      -
  ,     ,    
.FOLDOC

merge ().        -
 .  sort   .

 key ( ).        ALT. 
  SHIFT.   ,   . 
     emacs.

metacharacter (). ,      
    .    
   ( )     (
 ).        
,   . .     .

metadata ().   .       ,
       ,
    .

,          -
 (, ,    ),     (, , 
 )     ( ,   ,     ).

982  VII. 