(/). :
qnx/fsys
company/xyz
/company/xyz
Note: , .

, , ( nameloc). .

. . , , , .

, qnx_name_attach(). , qnx_name_locate().

QNX , . (UTC) 0 , 0 , 0 , 1 1970 . , TZ ( ).

, . sleep; sleep(). delay(), .

, , . POSIX Std 1003.4/Draft 9.

. . , ( Proc ). timer_create().

:

, . , , 9 . , 5 .

. :

: :
timer_settime()

, timer_delete().

ticksize qnx_timerperiod(). 500 50 .

, , timer_gettime().

- .

QNX (, ), , .

:

( ). , . , , .
: :
qnx_hint_attach()
qnx_hint_detach()

, . , ticksize.

, 50 , tick size. POSIX 1003.4 .

/

:

/

/ (I/O, Input/Output) QNX . / . QNX , ( ) , .

QNX . , - /, , , (.. ). , QNX.

/

, , open() /. , (Dev) /dev. open() /dev/xxx, /dev open() Dev ( ).

. . , , :
/ (Fsys)
/dev (Dev)
/dev/hd0 (Fsys)

, QNX (.. /) - , (.. /dev/hd0). . .
: : :
/dev/con1 /dev Dev
/dev/hd0 /dev/hd0 Fsys
/usr/dtdodge/test /Fsys

, , : 

prefix=pid,unit:prefix=pid,unit:prefix=pid,unit

pid - ID I/O, unit - , , . , Fsys 3 Dev 5, : 

/dev/hd0=3,a:/dev=5,a:/=3,e
: :
prefix
qnx_prefix_query()

QNX , . , . , . , QNX :
/dev/ser1
//10/dev/ser1 10
//0/dev/ser1
//20/usr/dtdodge/test 20

, //0

, , . , : 

//5 ls /

ls 5, , : 

ls /

. "/" , 5. , , , "/" 5, : !

, , , , ("/"). , , . , //9, :

/usr/home/luc

, :

//9/usr/home/luc

, " /usr/home/luc, 9- ".

, . , , 9, , 9 ( ). : 

ls /

//9, : 

ls //9/

, : 

//5 ls /

ls 5, - //9, ls //9/. .
: :
qnx_prefix_getroot()
qnx_prefix_setroot()
on

, , . , - , .

, (, ), , . , ( ///), .

, I/O. , . : 

prefix=-

, , ( , "/"). , (, 10), "/". : 

/=//10/

, (/) //10/. , /usr/dtdodge/test :

//10/usr/dtdodge/test

; 10 , .. //10. 10, , , open(). .

, . : 

/dev=5,a:/=//10/

, /dev, , , .

. , 20, : 

/dev/printer=//20/dev/spool

/dev/printer . , , 20 : 

/dev/fd0=//20/dev/fd0

, :

//20/dev/spool //20/dev/fd0

. . QNX . .

, , , .

( ), . , , .

, : 

cd //18/

() 18, , . cd dev, //18/dev.

, : 

cd /

, . , //9, , cd dev, //9/dev. , .

, . (///) , , , ( ). , , (.. ) .

cd

UNIX cd ( ) , . , - pwd, , cd.

QNX, , cd - "..". : 

cd /usr/home/luc/test/../doc

/usr/home/luc/doc, .

" ".

Note: , fullpath.

I/O, open() , (FD), , I/O . ( Sendfd().)

, , . PID FD, , open(). (OCB open control block) I/O.

, I/O OCB PID FD.

fig: i/pidfdocb.gif

PID FD OCB /.

OCB . , . open() OCB. , , lseek(), FD, FD.

, .

, , . FD.

fig: i/tmpfile.gif

A /tmp/file . B .

OCB. :

FD OCB, OCB , , OCB.

, lseek() , , , .

, , dup(), . , .

fig: i/dupfd.gif

, FD dup(). .

spawn() exec(), fcntl() FD_CLOEXEC.

:

(Fsys) . Fsys , , .

?

QNX - , , , . QNX ; Fsys:

. - - - .

Fsys . :

, inode ( ) . inode " (inodes)". , ID . :

ID ID , . , , setuid ( ID ) setgid ( ID ).

QNX . .

. - , ( " ").

- , . . - , . ( " (inodes)" " ").

, /usr/bill/file2.

fig: i/dirpath.gif

QNX /usr/bill/file2.

, , . , link().

, POSIX, . :

QNX - , "" , open() read(). - .

QNX . - .

, , . , , ( - / ). 60 .

fig: i/extents.gif

, , QNX . 





 


      , 
    ,      .
       ,    
  .


       
 " ".      
    ,    /.bitmap (
    "  
QNX").       
 .       
  .




    (inodes)


 QNX       .  
  .     
:  ,   "",   .
     .


    ,     
,  .     ,
 inode ( ).


      (..  ), 
 inode       .
       ,  inode 
     /.inodes,  
       inode.


,       ,    
        .




fig: i/twolinks.gif




          "more" 
"less".



   ,      
  /.inodes:




  :
:



    
 ln


   
 link()



 


  ,     ,
 .       ;
     .     
  ,        
,   ,  .   
    ,      .




  :
:

    
 rm


   
 remove()  unlink()



 


       . 
      :




  ""   ; " "
 ,   .


,  " "   "/" -   "/", -
    .




 


  -   ,    
  .      
/ - , open(), -     
  "".     
        
      .     ,
         
   .


    //1/usr/fred 
//2/usr/barney        ,
      ,    
 (  ).      
  :


//1/usr/fred --> //2/usr/barney

,       
      .    
       . 
      ,    :


//1/usr/eric/src/test.c --> //1/usr/src/game.c

Figure showing two nodes using symbolic links




  :
 :



  
ln (  -s)


  *
rm


,     
ls


* ,      
 ,     


     
.          
  .     unlink()
(   ), lstat()  readlink().


       ,  
    , ,  
.     ,  
   ;    
SYMLOOP_MAX    <limits.h>.




  (pipes)  FIFO



  (pipes)

  -   ,  
  /       -
     ,    
.      . 
   PIPE_BUF   <limits.h>.
         .


   ,    
 ,      
  .     ,
   .


   
         .
      (Shell).
:


ls | more

     ls 
      more.




  :
:



     
   ("|")


    
 pipe()  popen()







Note:
       
  (Pipe)    ,
    .   
   () /  
   ,    .

 







FIFO

FIFO -      ,    , 
 ,  FIFO    ,
     .




  :
:

 FIFO   
 mkfifo


 FIFO  
 mkfifo()


 FIFO   
 rm


 FIFO  
 remove()  unlink()




   


   , 
   :




 

   
        
  .  /   ,
          ,
        .


    , 
  / ,  .



-

- -     
    . -