                     Network Block Device (TCP С)
                                       
    - Network Block Device (NBD) ϸ߼¸ŪʤΤǡΥԥ塼
   ȳعǤΥԥ塼ǤϡۤưƤޤ
   
   NBD ȤϡͥȤ߹ȡLinux ϥ֥åǥХȤƥ⡼
   ȥФȤޤäơ饤ȥԥ塼 /dev/nd0
   ɽФϤĤǤ TCP ǥФ׵ꡢФϥǡ
   Фα򤷤ޤˡϡǥΰξʤơ
   (뤤ϥեåԡ֡Ȥʤǥ쥹Ǥ) ǡ̤Υ
   ԥ塼ΥǥΰѤΤѤǤޤNFS Ȥϰۤʤꡢ
   ΰˤɤʥե륷ƥǤ֤ȤǤޤNBD
   ϥ桼٥ץεưɬפʤΤǡ롼ȥե륷ƥ
   ˤѤǤޤ󡣤ˡ桼ɤǥ֥åǥХμ¹Ԥ
   Ǥޤ (ʪŪƱԥ塼򥵡Фȥ饤ȤȤ롼
   ץХåѤ̿ޤ)
   
   ưޤNBD ϤʤꤷƤ褦˸ޤ
   TCP  swap ϤǤʤȹͤƤޤϿ¤Ǥʤ
   ȤȽޤ -  TCP Ǥ swap ưǥåɥå
   ʤ褦ǤΤˤ Linux Υͥåȥؤ̤
   ѥå򤢤Ƥɬפޤ
   
   ǥХNBD ϥ᥸㡼ֹ 43, ޥʡֹ 0..n Ѥޤ (
    n  nbd.h ǽǤ)ɬפʻmknod ǤΥե
   ޤ塢ls -l /dev/ η̤ϼΤ褦ˤʤޤ -

brw-rw-rw-   1 root     root      43,   0 Apr 11 00:28 nd0
brw-rw-rw-   1 root     root      43,   1 Apr 11 00:28 nd1
...

   ץȥ롧桼ɥץ TCP åȤ³Ƥե
   ϥɥºݤΥͥɥ饤ФϤޤˡǡ
   ³ʤɤդʧɬפޤ󡣥ץȥϻפäñ
   Ǥ - ɥ饤Ф֥åǥХɤ褦ꤵСη
    "׵" ѥåȤޤ (ǡϤ٤ƥͥåȥХȽ
   Ǥ) -
   
  __u32 magic;        0x12560953 ǤʤФʤޤ
  __u32 from;         ɽФ⤷ϽߤΥХȰ
  __u32 len;          ɽФ⤷ϽߤΥХȿ
  __u64 handle;       ϥɥ
  __u32 type;         0 = ɽФ
                      1 = 
  ...                 ξ硢Τ˥ǡΥХĹ
                      ³ޤ

   λȡФϼι¤ "" ѥåȤ֤ޤ -
   
  __u32 magic;        ׵Ʊ
  __u64 handle;       ׵ᤫ饳ԡ줿ϥɥ
  __u32 error;        0 = 
                      0 ʳϥ顼
  ...                 ɽФǥ顼ʤä硢Τ˥ǡ
                      ΥХĹ³ޤ

   ܤ http://atrey.karlin.mff.cuni.cz/~pavel 򻲾ȤƤ
----------------------------------------------------------------------
ܸܹ <hng@ps.ksky.ne.jp>
    ë鳨 <jeanne@mbox.kyoto-inet.or.jp>
          ѱѤ <hotta@net-newbie.com>
