Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!decwrl!sun!pitstop!sundc!seismo!uunet!mcvax!unido!sbsvax!roeder
From: roeder@sbsvax.UUCP (Edgar Roeder)
Newsgroups: comp.os.minix
Subject: /dev/hd5
Keywords: Minix-ST, use of /dev/hd5 as Minix-Filesystem
Message-ID: <689@sbsvax.UUCP>
Date: 20 Feb 89 18:16:11 GMT
Organization: Universitaet des Saarlandes, Saarbruecken, W-Germany
Lines: 38

Last weekend i tried to address my SH205 as one Filesystem via /dev/hd5 under
Minix. I ran across one serious problem. At boot time the physical sector 0 of
the harddisk is used to determine the size of the harddisk and the available
partitions. When you address it as a single filesystem via minor number 5 the
same sector 0 is now used to hold data. The next time you try to mount this
drive after a reboot the system refuses this because the partioning info is not
valid anymore.
My proposed solution is to use minor 5 to address the whole disk without sector
0. You have still access to this sector via minor 0. A patch to stwini.c
follows.

	- Edgar

----------------------------- start of patch -----------------------------------

*** stwini.c.old	Mon Feb 20 18:43:31 1989
--- stwini.c	Mon Feb 20 18:43:17 1989
***************
*** 105,111 ****
  		if (pi[minor].pi_flag == PI_INVALID)
  			pi[minor].pi_size = 0;
  	}
! 	pi[minor].pi_size = hi.hd_size;
    }
    TRACE(
  	for (r = 0; r < MAX_MINOR; r++)
--- 105,113 ----
  		if (pi[minor].pi_flag == PI_INVALID)
  			pi[minor].pi_size = 0;
  	}
! 	/* physical sector 0 is needed for partition info */
! 	pi[minor].pi_start = 1;
! 	pi[minor].pi_size = hi.hd_size - SECTOR_SIZE;
    }
    TRACE(
  	for (r = 0; r < MAX_MINOR; r++)

------------------------------ end of patch ------------------------------------