[NTLUG:Discuss] cfdisk and bootable partition flag

Robert Pearson e2eiod at gmail.com
Wed Jan 11 17:35:50 CST 2006


On 1/11/06, ntlug at levelofdetail.com <ntlug at levelofdetail.com> wrote:
> Thanks, Patrick. Yes, that helps. I should have mentioned it is a
> standard install with Grub.
>
> I have another machine with Ubuntu on it. It also uses Grub, standard
> install, booting one OS only. The boot partition is indicated by both
> fdisk and cfdisk. On this machine I can't find grub.conf anywhere - not
> in /etc or /boot. There is a /boot/grub directory but no conf file in
> it.

I use GRUB to boot my two disk, dual boot, one OS per disk system.

"/dev/sda" is a SATA disk with SuSE 9.3 loaded.
"/dev/hda" is an IDE disk with Windows 2000 loaded.
In addition I have external USB drives of 120, and 20GB.
There are two USB "jump" drives of 256MB and 1GB.

When I run "fdisk -l", as root, any partition marked bootable
is assigned an asterisk "(*)" by fdisk. Here is what I get---

=======================================================
Disk /dev/sda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1        9438    75810703+  83  Linux
/dev/sda2            9439        9728     2329425   82  Linux swap / Solaris

Disk /dev/hda: 80.0 GB, 80032038912 bytes
255 heads, 63 sectors/track, 9730 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/hda1   *           1         798     6409903+   7  HPFS/NTFS
/dev/hda2             799        2428    13092975    f  W95 Ext'd (LBA)
/dev/hda5             799        1086     2313328+   7  HPFS/NTFS
/dev/hda6            1087        2428    10779583+   7  HPFS/NTFS

Disk /dev/sdb: 120.0 GB, 120034123776 bytes
255 heads, 63 sectors/track, 14593 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1        4079    32764536    c  W95 FAT32 (LBA)
/dev/sdb2            4080        8158    32764567+   c  W95 FAT32 (LBA)
/dev/sdb3            8159       12237    32764567+   c  W95 FAT32 (LBA)
/dev/sdb4           12238       14592    18916537+   c  W95 FAT32 (LBA)

Disk /dev/sdc: 1047 MB, 1047265280 bytes
64 heads, 32 sectors/track, 998 cylinders
Units = cylinders of 2048 * 512 = 1048576 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1   *           1         998     1021935+   6  FAT16
Partition 1 has different physical/logical endings:
     phys=(996, 63, 32) logical=(997, 63, 31)

Disk /dev/sdd: 257 MB, 257949696 bytes
255 heads, 63 sectors/track, 31 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdd1               1          31      248976    b  W95 FAT32

Disk /dev/sde: 20.0 GB, 20003881472 bytes
255 heads, 63 sectors/track, 2432 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sde1               2        2431    19518975    f  W95 Ext'd (LBA)
/dev/sde5               2        2431    19518943+   c  W95 FAT32 (LBA)

=======================================================
When I run your command of "cfdisk -P /dev/sda" I get---

Usage:
Print version:
        cfdisk -v
Print partition table:
        cfdisk -P {r|s|t} [options] device
Interactive use:
        cfdisk [options] device

Options:
-a: Use arrow instead of highlighting;
-z: Start with a zero partition table, instead of reading the pt from disk;
-c C -h H -s S: Override the kernel's idea of the number of cylinders,
                the number of heads and the number of sectors/track.

Copyright (C) 1994-2002 Kevin E. Martin & aeb

=========================================================

and the same error message for "/dev/hda".

=========================================================
When I run "cfdisk -P s /dev/hda", as root, I get---

Partition Table for /dev/hda

               First       Last
  # Type       Sector      Sector   Offset    Length   Filesystem Type (ID) Flag
-- ------- ----------- ----------- ------ ----------- -------------------- ----
  1 Primary           0    12819869     63    12819870 HPFS/NTFS (07)       Boot
  2 Primary    12819870    39005819      0    26185950 W95 Ext'd (LBA) (0F) None
  5 Logical    12819870    17446589     63     4626720 HPFS/NTFS (07)       None
  6 Logical    17446590    39005819     63    21559230 HPFS/NTFS (07)       None
   Pri/Log    39005820   156312449      0   117306630 Free Space           None


and for "dev/sda"---

Partition Table for /dev/sda
               First       Last
  # Type       Sector      Sector   Offset    Length   Filesystem Type (ID) Flag
-- ------- ----------- ----------- ------ ----------- -------------------- ----
 1 Primary           0   151621469     63   151621470 Linux (83)           Boot
 2 Primary   151621470   156280319      0     4658850 Linux swap / So (82) None
   Pri/Log   156280320   156296384      0       16065 Free Space           None


and "cfdisk -P t /dev/sda" gives---

Partition Table for /dev/sda

         ---Starting---      ----Ending----    Start     Number of
  # Flags Head Sect Cyl   ID  Head Sect Cyl     Sector    Sectors
-- ----- ---- ---- ---- ---- ---- ---- ---- ----------- -----------
 1  0x80    1    1    0 0x83  254   63 1023          63   151621407
 2  0x00  254   63 1023 0x82  254   63 1023   151621470     4658850
 3  0x00    0    0    0 0x00    0    0    0           0           0
 4  0x00    0    0    0 0x00    0    0    0           0           0

and "cfdisk -P t /dev/hda" gives---

Partition Table for /dev/hda

         ---Starting---      ----Ending----    Start     Number of
  # Flags Head Sect Cyl   ID  Head Sect Cyl     Sector    Sectors
-- ----- ---- ---- ---- ---- ---- ---- ---- ----------- -----------
 1  0x80    1    1    0 0x07  254   63  797          63    12819807
 2  0x00    0    1  798 0x0F  254   63 1023    12819870    26185950
 3  0x00    0    0    0 0x00    0    0    0           0           0
 4  0x00    0    0    0 0x00    0    0    0           0           0
 5  0x00    1    1  798 0x07  254   63 1023          63     4626657
 6  0x00  254   63 1023 0x07  254   63 1023          63    21559167

I assume the "0x80" under flags indicates a bootable partition.




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