man(1) Manual page archive


     SYS(4)                                                     SYS(4)

     Name
          sys - Machine boxes.

     Synopsis
          /b/sys/debug
          /b/sys/cmd
          /b/sys/null
          /b/sys/time
          /b/sys/atime
          /b/sys/random
          /b/sys/ads

     Description
          Boxes under /b/sys provide system services that either
          affect the whole machine or do not fit well on other place.

          /b/sys/debug
               is used to toggle debug flags in the kernel. Its con-
               tents appear to be the set of active debug flagseach
               one is a character. An string copied into it would
               either set or clear (if started by "-") the debug flags
               found in the string. Use grep defdbg on the source to
               see which debug flags are defined.

          /b/sys/cmd
               is a placeholder used to send system-wide commands to
               the machine, such as halt. No commands are defined yet.

          /b/sys/null
               is the great bit bucket. It discards data copied into,
               and appears to be always empty when data is copied from
               it.

          /b/sys/time
               is the node time in binary format. It is four bytes
               with the number of seconds since epoch.

          /b/sys/atime
               is the node time printed as a string.

          /b/sys/random
               contains a random number in binary format (four bytes).

          /b/sys/ads
               contains the set of boxes advertised to the network by
               the kernel at this machine (other boxes may be adver-
               tised by user processes). Copy a string made of two
               names (box name, ad name) separated by white space to
               stablish a new ad. Ads are sent upon request and also
               every 30 seconds. Ads are requested every time

     SYS(4)                                                     SYS(4)

               import(2) is used to mount network ads.

     Example
                    → /b/sys/ads
                    /b/mem    /mem
                    → /b/sys/ads
                    /b/proc   /proc

          To advertise /b/mem as /mem and /b/proc as /proc.

     Source
          /src/b/port/sysbox.c

     See also
          import(2) and →(1).

     Bugs
          There are some boxes missing from /b/sys. The reason is that
          no program on top of Plan B needs them yet. They will be
          added.