User Namespace

The user namespace provides a namespace for naming human users in a computing environment. User names are identified by the prefixes user/or _user/.

Users are named in user contexts. The user context has a single-level namespace and contains bindings of user names to user contexts. A user context allows you to name objects relative to a user, such as files, services, or resources associated with the user.

In the Solaris operating environment, user names correspond to Solaris login IDs. For example, _user/inga identifies a user whose login ID is inga.

File Namespace

A file namespace (or file system) provides a namespace for naming files. File names are identified by the prefixes fs/or _fs/. For example the name fs/etc/motd identifies the file motd which is stored in the /etc directory.

The file namespace is described in more detail in ."Files-Based naming files" and file contexts are discussed in "File Contexts Administration".

Service Namespace

The service namespace provides a namespace for services used by or associated with objects within an enterprise. Examples of such services are electronic calendars, faxes, mail, and printing. Service names are identified by the prefixes service/ or _service/.

In the Solaris operating environment, the service namespace is hierarchical. Service names are slash-separated (/) left-to-right compound names. An application that uses the service namespace can make use of this hierarchical property to reserve a subtree for that application. For example, the printer service reserves the subtree printer in the service namespace.

FNS does not specify how service names or reference types are chosen. These are determined by service providers that share the service namespace. For example, the calendar service uses the name _service/calendar in the service context to name the calendar service and what is bound to the name calendar is determined by the calendar service.

Service Name and Reference Registration

Sun Microsystems, Inc., maintains a registry of the names bound in the first level of the service namespace. To register a name, send an email request to fns-register@sun.com, or write to:

FNS Registration Sun Microsystems, Inc., 4150 Network Circle Santa Clara, CA 95054

Please include a brief description of the intended use of the name and a description of the format of the reference that can be bound to that name.

Printer Namespace

The printer namespace provides a namespace for naming printers. The printer namespace is associated with (subordinate to) the service namespace. In other words, printer service and the printer namespace is one of the services in the service namespace. Printer names are identified by the prefixes service/printer or _service/printer. For example, service/printer/laser1 identifies the printer named laser1.

Significance of Trailing Slash

The trailing / names objects in the next naming system. You need it whenever you are going from one naming system to another.

For example, in the name, org/east.sales/service/printer the slash between org and east.sales is a component delimiter as described above and the slash that trails after the last element in the organization name (sales/) separates the service namespace from the organizational unit namespace. Thus, org/west.sales/service/printer names the printer service of the west.sales organization unit.

FNS Reserved Names

FNS reserves for its own use all the atomic names listed in Table 25-25 as namespace identifiers. For example: _orgunit, org, _site, site, and so forth. This limitation applies to contexts in which the namespace identifiers can appear, as defined by the arrangement of namespaces in "Structure of the Enterprise Namespace". FNS does not otherwise restrict the use of these atomic names in other contexts.

For example, the atomic name service is used as a namespace identifier relative to a user name, as in user/fatima/service/calendar, to mean the root of user fatima's service namespace. This does not preclude a system from using the name service as a user name, as in user/service, because FNS specifies that the context to which the name user/ is bound is for user names and not for namespace identifiers. In this case, service is unambiguously interpreted as a user name. On the other hand, you should not create a directory named user because /user/mikhail would cause confusion between the user mikhail and the file (or subdirectory) /user/mikhail.

Composite Name Examples

This section shows examples of names that follow FNS policies. (See Table 25-26 for a summary of these policies.)

The specific choices of organization names, site names, user names, host names, file names, and service names (such as calendar and printer) are illustrative only; these names are not specified by FNS policy.

Composing Names Relative to Organizations

The namespaces that can be associated with the organization namespace (_orgunit, orgunit, or org) are: user, host, service, fs, and site.

For example:

• orgunit/doc.com/site/videoconf.bldg-5 names a conference room videoconf located in Building 5 of the site associated with the organization doc.com. (You can also use the alias org for orgunit to form, org/doc.com/site/videoconf.bldg-5.)

• orgunit/doc.com/user/mjones names a user mjones in the organization doc.com.

• orgunit/doc.com/host/smptserver1 names a machine smptserver1 belonging to the organization doc.com.

• orgunit/doc.com/fs/staff/agenda9604/ names a file staff/agenda9604 belonging to the organization doc.com.

• orgunit/doc.com/service/calendar names the calendar service for the organization doc.com. This might manage the meeting schedules for the organization.

Composing Names Relative to Users

The namespaces that can be associated with the user namespace are service and fs.

• user/helga/service/calendar names the calendar service of a user named helga.

• user/helga/fs/tasklist names the file tasklist under the home directory of the user helga.

Composing Names Relative to Hosts

The namespaces that can be associated with the hosts namespace are service and fs.

• host/mailhop/service/mailbox names the mailbox service associated with the machine mailhop.

• host/mailhop/fs/pub/saf/archives.96 names the directory pub/saf/archives.96 found under the root directory of the file system exported by the machine mailhop.

Composing Names Relative to Sites

The namespaces that can be associated with the sites namespace are service and fs.

• site/bldg-7.alameda/service/printer/speedy names a printer speedy in the bldg-7.alameda site.

• site/alameda/fs/usr/dist names a file directory usr/dist available in the alameda site.

Composing Names Relative to Services and Files

No other namespaces can be associated with either the files (fs) or services (service) namespaces. For example, you cannot compose a name such as /services/calendar/orgunit/doc.com. In other words, you cannot compose a compound name relative to either the files or the service namespace. You can, of course, compose a file or service name relative to some other namespace such as /user/esperanza/service/calendar.

Structure of the Enterprise Namespace

FNS policies define the structure of the enterprise namespace. The purpose of this structure is to allow easy and uniform composition of names. This enterprise namespace structure has two main rules:

• Objects with narrower scopes are named relative to objects with wider scopes.

• Namespace identifiers are used to denote the transition from one namespace to the next.

Table 25-26 isf FNS policies for arranging the enterprise namespace. The following table shows an example of a namespace layout that follows these FNS policies.

Table 25-26 Policies for the Federated Enterprise Namespace

Namespace Identifiers	Subordinate Namespaces	Parent Context	Namespace Organization	Syntax
orgunit _orgunit org	Site, user, host, file system, service	Enterprise root	Hierarchical	Dot-separated right-to-left
site _site	Service, file system	Enterprise root, organizational unit	Hierarchical	Dot-separated right-to-left
user _user	Service, file system	Enterprise root, organizational unit	Flat	Solaris login name
host _host	Service, file system	Enterprise root, organizational unit	Flat	Solaris host name
service _service	Application specific	Enterprise root, organizational unit, site, user, host	Hierarchical	/ separated left-to-right
fs   _fs	None	Enterprise root, organizational unit, site, user, host	Hierarchical	/ separated, left-to-right
printer	None	Service	Hierarchical	/ separated left-to-right

Figure 25-1 Example of an Enterprise Namespace

The namespace of an enterprise is structured around a hierarchy of organizational units. Names of sites, hosts, users, files, and services can be named relative to names of organizational units by composing the organizational unit name with the appropriate namespace identifier and object name.