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Newsgroups: comp.os.386bsd.misc,comp.os.386bsd.questions
Subject: I lost my disklabel and hence my 386bsd root [was :disklabel problem, please help! [URGENT]]
Message-ID: <CEvysJ.F9E@latcs1.lat.oz.au>
From: wongm@ipc4.lat.oz.au (M.C. Wong)
Date: Thu, 14 Oct 1993 12:02:42 GMT
Sender: news@latcs1.lat.oz.au (news)
Organization: Comp Sci, La Trobe Uni, Australia
Nntp-Posting-Host: ipc4.lat.oz.au
Lines: 87


Hi,
  I posted this tragedy before but only got one reply, and it doesn't answer the 2
questions I asked, and I think I should repost it since the ACTUAL questions
I am asking are further down the page . In summary, I thrash/lost my disklabel
on my wd0 (CP3544 IDE), and when doing disklabel -r wd0, it wil give some disk
geometry followed by NO 386bsd partition information.
                     ^^
  Sorry for the repost but I am in real deep shit and I need to restore my system
urgently! Below is the thing in details as posted orginally!

  Here is my config :
  - OS : 386bsd-0.1 + pk-0.2.4
  - Hard disk : Conner Peripheral 3544 (544MB) with following partitions :

    FDISK partition
    ----------------
    Partition	Type	Volume-Label	Mbytes	System	Usage
    ---------------------------------------------------------
    C:1         PRI-DOS    DOS6		150	FAT16	30%
      2		NON-DOS			350		70%
                (386bsd)

    PFDISK partition
    ----------------
    geometry 1023 16 63 (cyls heads sectors)
    #	ID	First(cyl)	Last(cyl)	Name	# start,length(sectors)
    ---------------------------------------------------------------------------
    1	6		0	      304	DOSbig	# 63, 307377
    2	0		0		0	empty	# 0, 0
    3	0		0		0	empty	# 0, 0
    4   165	      305	     1022	unkown	# 307440, 723744
						(386bsd)
    #   note : last(4): phys=(1023, 15, 63) logical=(1022, 15, 63)

  - Within  the 386bsd partition I had parition a: followed by b: of 5 Mb, ie
    a: is about 345Mb, ie :
    a: (cyl. 305 - X) , 4.2BSD, [fsize = 1024, bsize = 8192, cpg = 16]
    b: (cyl.   X - 1022), swap.
    c: (cyl. 305 - 1022), note I reserve cyl 1023 unused!

    I am not too sure if the size and offset field can be derived from the
PFDISK information ? I can't remember what is X. Also, sec/cyl = 1008, 
bytes/sec = 512 bytes. But with a bit of calculation in backward, I get the 
following : (Am I correct ?)

	size(sect)	begin(sect) end(sect)	begin(cyl) end(cyl)
	--------------------------------------------------------------------
      a:  713504	   307440   1019936	       305	1011.84127
      b:   10240 (5Mb)	  1019936   1030176	   1011.84127   1022 
      c: 1030176           307440   1030176            305      1022 

  Why did I get end cyl 1011.84127 for a: ? Can I simply round it up to 1012
without losing any data?

  I edited the disklabel last night (disklabel -e -r wd0) to attempt to add
in an entry e: for my MSDOS partition, but somehow it screwed up and I lost
all the disklabel, ie my system will no longer boot from wd0. If I boot from
the fixit floppy, I can no longer mount wd0a, as it comlaint wd0a not
configured, even though it is there, and disklabel -r wd0 gives me all the disk
geometry without BSD partition info at all. And the worst thing is I can't
quite remeber the offset and end cylinders (sectors) in the original disklabel.
All I know is that, my swap (b:) is still the original 5Mb, and the rest is a:.

  My questions are :
  1) If I figure out all of the missing figures in the above disklabel entries
     correctly and re-disklabel wd0 from floppy. will I be able to restore my 
     system ? Are the above backward calculation correct ? If re-disklabel
     doesn't work, is there any other alternative ?

  2) I only have 1 fixit floppy which is read only, without the right mount
     that can remount my root to writable, no termcap file in /etc. So I am
     stuck with no other alternative.

  I wonder can someone help me out with this problem, ie verify if 1) will
work , and if so please can you send me a bootable floppies (raw format)
with the right tools (vi, termcap, mount etc) to fix the problem ?

  Many thanks in advance and email replies please as I am in deep shit!

- wongm@latcs1.lat.oz.au (M.C Wong)
-- 
- wongm@latcs1.lat.oz.au


-- 
- wongm@latcs1.lat.oz.au