[comp.os.minix] mkfs glitch in 1.5.10

danson@udel.edu (Douglas Anson) (02/23/91)

I am trying to create a file system on my 2nd MFM 20Mg hard drive
using mkfs on MINIX 1.5.10.  I would like to use the entire disk so
I have used fdisk (in DOS) to make a single partition and then
(in minix) I type: mkfs /dev/hd6 20842.  The command returns fine
with a file system made on my 2nd harddrive.  However, my problem
is that when I return to DOS, my 2nd hard drive is still visible to
DOS.  

Has anyone else encountered this problem?  Any crafty solutions?
BTW, I use a 286 with 4Meg RAM...1.5.10...

cheers!

doug anson
danson@dewey.udel.edu
The Univ. of Del.

wayne@ledgepc.uucp (Wayne Brown) (02/24/91)

From article <45603@nigel.ee.udel.edu>, by danson@udel.edu (Douglas Anson):

[ . . . ]

> I have used fdisk (in DOS) to make a single partition and then
> (in minix) I type: mkfs /dev/hd6 20842.  The command returns fine
> with a file system made on my 2nd harddrive.  However, my problem
> is that when I return to DOS, my 2nd hard drive is still visible to
> DOS.  

When you create a partition with DOS fdisk, it is marked as a DOS partition.
Just run Minix fdisk and mark it as a Minix partition.  (If you don't make
any other changes, it shouldn't be necessary to

ching@brahms.amd.com (Mike Ching) (02/26/91)

In article <cechew.667449546@sol1> cechew@sol1.cs.monash.edu.au (Earl Chew) writes:
>danson@udel.edu (Douglas Anson) writes:
>>with a file system made on my 2nd harddrive.  However, my problem
>>is that when I return to DOS, my 2nd hard drive is still visible to
>>DOS.  
>
>>Has anyone else encountered this problem?  Any crafty solutions?
>>BTW, I use a 286 with 4Meg RAM...1.5.10...
>
>I think that the problem is that mkfs *doesn't* write to the first kb
>(bootblock) of the named medium. This leaves your old partition table intact so
>DOS quite cheerfully thinks that you still have a valid file system. To solve
>this problem try:
>
>	dd if=/etc/termcap of=/dev/hd6 bs=512 count=1
>
>This will write the first 512 bytes of /etc/termcap (pick any other rubbish
>file you want) over the partition table of hd6.
>

If you haven't used fdisk to make the partition type MINIX, then that is
what you should do to make the partition invisible to DOS. Fdisk under
DOS can't do this so you can change it under MINIX or compile the MINIX fdisk
under DOS.

Mike Ching

cechew@sol1.cs.monash.edu.au (Earl Chew) (02/27/91)

ching@brahms.amd.com (Mike Ching) writes:

>In article <cechew.667449546@sol1> cechew@sol1.cs.monash.edu.au (Earl Chew) writes:

	[.. some partial rubbish ..]

>If you haven't used fdisk to make the partition type MINIX, then that is
>what you should do to make the partition invisible to DOS. Fdisk under
>DOS can't do this so you can change it under MINIX or compile the MINIX fdisk
>under DOS.

This now has been pointed out by several people. Strictly speaking, my
original reply was wrong :-(

If, however, you don't want to use a partition table at all, and want to use
the *ENTIRE* disk for a Minix file system, then my reply may be true.

Earl
--
Earl Chew, Dept of Computer Science, Monash University, Australia 3168
EMAIL: cechew@bruce.cs.monash.edu.au PHONE: 03 5655778 FAX: 03 5655146
----------------------------------------------------------------------

hodgen@infko.UUCP (Wayne Hodgen) (02/27/91)

>>>with a file system made on my 2nd harddrive.  However, my problem
>>>is that when I return to DOS, my 2nd hard drive is still visible to
>>>DOS.  
  
>>      dd if=/etc/termcap of=/dev/hd6 bs=512 count=1
>>
>>This will write the first 512 bytes of /etc/termcap (pick any other rubbish
>>file you want) over the partition table of hd6.
  
>what you should do to make the partition invisible to DOS. Fdisk under
>DOS can't do this so you can change it under MINIX or compile the MINIX fdisk

No. I use DrDos 5.0 and have a second drive with the partition table created
by MINIX and marked as MINIX (1.5.10) and DOS _still_ recognised the drive.
After a dd command (in MINIX) as above it could no longer *see* the drive.
But be sure to use a file > 512 bytes (I used a command from /bin) or dd 
will end with 0+1 blocks and thus will have written NOTHING.


-- 
Wayne Hodgen          | hodgen@infko.UUCP       |  All Opinions (c) Me 1991   
Uni Koblenz,          | (..!unido!infko!hodgen) |  Stuff your "reality",
Rheinau 3-4,          | Voice: +49 261 9119-418 |  all *I* need is Hack!!!     
5400 Koblenz, Germany | Fax:   +49 261 37524    |  "Dark Lurker" strikes again.