From mboxrd@z Thu Jan 1 00:00:00 1970 From: tlaronde@polynum.com Date: Sat, 13 Nov 2010 09:31:43 +0100 To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> Message-ID: <20101113083143.GA1101@polynum.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.3i Content-Transfer-Encoding: quoted-printable Subject: Re: [9fans] p9p factotum available for plan 9 Topicbox-Message-UUID: 7bf59d9e-ead6-11e9-9d60-3106f5b1d025 On Fri, Nov 12, 2010 at 02:20:35PM -0800, ron minnich wrote: > On Fri, Nov 12, 2010 at 2:15 PM, Eric Van Hensbergen = wrote: >=20 > > No, that's true. =A0I think this is actually a huge open issue for > > existing distributed file systems in general and I'm not sure of a > > good way around. >=20 > yeah, we had lots of discussion of this about 8 years ago with 9grid > and never worked it out. What's your global identify? How do you name > it? How do you map it to a local identity? I have no clue. The problem with strings is that they are human oriented and human dependent, on mood and/or trend. Numbers are agnostic. Isn't a solution =E0 la IP network numbers possible? I mean, a user, whatever string is locally associated to it (and this may change), is uniquely identified by a number that could encode a domain (with some numbers being absolutely local), the conversion between string to number being local (I'm called "god" on my personal systems, and may be called "dummy" elsewhere; well, in fact "god" is "root" on Unices, and this=20 "god" is only a local thing, with external systems don't believing in it at all), and negociation being only with numbers. And separate logical user from physical user: a physical user can be, depending on the task, several distinct logical users; but the reverse is true: several distinct physical users can be an uniq logical user. This changes the way one thinks about the sharing of randomly writable files: only "the" (logical) user of a file can randomly write=20 (by randomly, I mean not append) a file; but there can be several=20 concurrent instances of "the" user writing to the file (an instance of a user is called a terminal; and a terminal is a temporary view of the data). And there are group writable files that are only append writable so long as a new record doesn't invalidate the previous ones [partition] (hence distinct logical users sharing a group writable file don't care about other writes when reading; when writing, an identifier is returned, and if the record already exists, added by another user, the existing identifier is returned, else it is added and the new identifier is returned). The use of numbers mapping to a string that can change is the principle I have adopted with my CVS: the "projects" are only numbers, and if the mood (or the "marketing") change, only the string associated changes, the hierarchy is left alone since the numbers are fixed from start. --=20 Thierry Laronde http://www.kergis.com/ Key fingerprint =3D 0FF7 E906 FBAF FE95 FD89 250D 52B1 AE95 6006 F40C