port/sd.h		2000/0506		Created.
		2000/0526
		2000/0531
		2000/0607
		2000/0617
		2000/0706
		2000/0809
		2000/1129		Created.
		2001/0527		Convert to 9P2000 — change name and user to pointers.
		2001/0905		In SDev: add Ref, change unit number. In SDifc, add probe, clear, stat.
		2001/1022		Format edits. Comment edits.
		2002/0402		Change rawinuse to a ulong.
		2002/0404		Remove Log.
		2002/0406		Move typedefs to top. Add SDcache and SDwp.
		2003/0407		Remove SDunit.rendez.