Convert Device Mapper into Location Service

[Jiri Svoboda]

(Was: Eliminate Device Mapper) Knights, new plan: Devmap will not be eliminated, but converted into a Location Service. Location service functionality consists of two major parts:

• Look up service by name (naming, white pages)
• Look up service by type (trading, yellow pages)

Devmap already supports the first part. The tasks required are thus:

• Rename devmap to loc, devfs to locfs
• Implement loc categories, a replacement for devman classes
• Make loc categories available through locfs
• Support for easy construction of unique service names

After this is done, devman will be updated accordingly:

• Changes in devman to utilise loc categories
• Route connections directly from loc to server, not through devman
• Optionally implement devfs companion server for devman (not necessary)

[Jiri Svoboda]

Working on this in ​https://code.launchpad.net/~jsvoboda/helenos/loc

[Jiri Svoboda]

I think I can close this ticket since the basic task is done. Summary of what has and what hasn't been implemented follows.

Implemented:

• Rename devmap to loc, devfs to locfs
• Implement loc categories, a replacement for devman classes
• Changes in devman to utilise loc categories

Not implemented:

• Make loc categories available through locfs
  • Available through locinfo, though
• Support for easy construction of unique service names
  • Drivers don't need it, only regular servers might benefit
• Route connections directly from loc to server, not through devman
  • Should be done, alhtough clients are unaware of this
• Optionally implement devfs companion server for devman (not necessary)
  • This does not actually seem useful.