.TH CNSTR 6 .SH NAME cnstr \- Plan B volume constraints and attributes .SH DESCRIPTION .PP The Plan B .IR bns (4) program permits the application to mount at a given mount point those volumes whose names and attributes match the ones given as arguments, as said in .IR planb (1). .PP Volume attributes can be used as constraints to determine which ones of the volumes available for a given mount point are of interest for the application. A constraint is a set of values for attributes that refer to properties of the resource volume. Both volume announces and volume mount requests carry a constraint used to pair them. .PP A constraint is a single argument, field, or string. Its format is a set of .IR attr = value pairs delimited by white space. No space may be around the equal sign. Also, when using .IR rc (1), it is important to quote all the attribute/value pairs together, or they would become different constraints, and not a single one. .SH ATTRIBUTES .PP By convention, the following attribute names and values are used through the system, This convention should be followed or users will not know how to request a given property for a resource. Of course, this is highly regional and the version shown here corresponds to customs at URJC. .LP .ta +10, +10, +10, +10 .br .di x \ka .br .di .in \nau .ti0 Attribute Name Values Description .in \nau .ti0 Type type Type for the resource serviced. Usually corresponds to the data format for the device involved. .ti0 text text without null characters. .ti0 bin program binary .ti0 dir file hiearchy .ti0 pcm audio PCM data. .ti0 mp3 MPEG 2 layer 3 data. .ti0 Arch arch Architecture for the resource. Commonly used for .B bin types. .ti0 386 Plan B (or Plan 9), 386. .ti0 arm Plan B (or Plan 9), ARM. .ti0 lin Linux on 386 PC. .ti0 win Windows on 386 PC. .ti0 sym Symbian, native. .ti0 UI gui User interface service. Identifies the type of device available. .ti0 big Large graphics device .ti0 small Small graphics device .ti0 txt Text only device .ti0 location loc Name used to represent the location of the volume. Corresponds to a directory in .B /where that keeps context for the given location. .ti0 .ti0 user user Identifier used for the user, to identify volumes of interest for (or owned by) a particular user. .ti0 machine sys Identifier used for the machine, to identify volumes served by that particular machine. .ti0 domain dom Identifier used for the adminstrative domain, to locate volumes within domains. .ti0 Con net Connection. Specifies the quality of the link used to reach the volume. .ti0 ok Latency seems to be ok. .ti0 bad Latency is a bad one. .LP Other types and values not documented here may exist, although those commonly used should be described above. The convention is that attributes not listed here are not standard at URJC. .SH "SEE ALSO" .IR planb (1), .IR namespace.planb (4), .IR bns (8), .IR mount (2).