Coda File System

Suggested range for server number in /vice/db/servers ?

From: LEE, Yui-wah <>
Date: Fri, 20 Nov 1998 14:43:45 +0800 (CST)
I wrote:
> The entries in /vice/db/servers must be uniquely numbered.  For example,
> the file in my setup is:
>   [root_at_violin db]# cat servers
>   xylophone               128
>   violin                  129
> The man page also said that we should avoid using number in the
> range 0-127 (decimal).  I am not sure whether this restriction
> is still true.

Jan <> wrote:
> 3 on the SCM server, add an entry for the new machine in /vice/db/servers
>   (every host must have a unique number. This unique number should fall in
>   the range of 1 to 255)

After re-reading the man page, I am now puzzled.  The man page of
/vice/db/servers (in Section 5) reads:

       Each  file server has a file, /vice/db/servers, which maps
       server names to numbers.  The server  numbers  are  8  bit
       numbers  so  a  maximum  of  256 servers can be supported.
       Once a server number has been  assigned,  it  may  not  be
       reused.  You should not reassign a server a new id without
       initializing the server.

       The server numbers are used in too many  places,  probably
       the  most  important  is  in the creation of volumes.  The
       server creating a volume uses its  server  number  as  the
       first  byte  of the four-byte volume identification number
       in order to ensure uniqueness.

       NOTE: Replicated volume numbers must also be unique, so we
       reserve part of the range, 0-127 (0-7F hex), for this pur-
       pose.  Real server numbers must not be allocated from  the
       other subrange, and vice-versa.

When the man page is talking about the reserved range (0-127), it is
referring to the "replicated volume number" but not the "server number".
So what I said in the quote may be a mis-interpretation ?  But then
what is the "replicated volume number" ? In the file, we only need
to supply the "server number".  I (probably wrongly) concluded that we
should use number outside of the range 0-127 (but within the range 0-255)
because also of the concrete example in the same man page:

       The  format  of  the  file  is  the full server name (e.g. followed by a  tab  and  then  the
       servers  number.  Any line beginning with a "is considered
       a comment and is ignored.  The  following  is  an  example
       servers file:

       MAHLER.CODA.CS.CMU.EDU          201
       GRIEG.CODA.CS.CMU.EDU           204

-- Clement

Yui-wah LEE (Clement)                              Tel: (852)-26098412
Department of Computer Science and Engineering,    Fax: (852)-26035024 
The Chinese University of Hong Kong     Email:
Received on 1998-11-20 01:43:31