Virtual Processes

Some things don't map well to files, directories, or filesystems, but you may wish to import them into Linux at a low level in order to manipulate them in a similar way. Many of these may resemble processes.

• They start at a certain time and may stop at some point.

• They consume various sorts of resources while running.

• They may be in various states at different times, such as actively running, stopped, or waiting for an event.

It may make sense to represent such things as Linux processes, and it will be possible to create UML processes that represent the state of something external to the UML instance. This could be something very close to a process, such as a server on the host, or it could be something very unlike a process, such as a project.

This "virtual" process would appear in the UML instance's process list with all the attributes of a normal process, except that these would be fabricated from whatever it is representing. As with the filesystem example, actions performed on one of these processes would be reflected out to the real thing it represents. So, sending a signal to a virtual process that represents a service on some machine elsewhere on the network could shut down that service. Changing the virtual process's priority would have the analogous effect on the processes that belong to that service.

Representing a project as a "virtual" process is not as good a fit. It is hard to imagine that a high-level manager would sit in front of a process listing, look at processes representing projects within the company, and change their priorities or cancel them by clicking on a Linux process manager. Some things resemble processes, but their attributes don't map well onto Linux processes.

Representing network services as UML processes and managing them as such doesn't seem to me far fetched. Neither does representing hosts as a whole. Machines can respond to signals on their process representatives within the UML instance by shutting down or rebooting, and the status of a machine seems to map fairly well onto the status of a process.

Processes are more limited in this regard than filesystems are since they can't contain arbitrary data, such as names and file contents, and they have a limited number of attributes with fairly inflexible semantics. So, while I can imagine a synthetic filesystem being used to manage personnel in some sense, I don't think synthetic processes can be used in a similar way. Nevertheless, within those limits, I think there is potential for managing some process-like entities as synthetic UML processes and using that capability of UML to build a control console for those entities.