Author Topic: Same partition named hdb and sdb. Is there a difference?  (Read 414 times)

Offline batzilla

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Same partition named hdb and sdb. Is there a difference?
« on: October 08, 2012, 10:45:03 AM »
I'm a little confused with my new install of PCLinuxOS 2012.08-KDE.  My old 2009 version of pclinuxos showed my partitions as hda, hdb, etc.  Now my new install labels them sda and sdb.  fdisk says sda, /boot/grub/menu.lst says hd1, and /etc/fstab says sdb.  It boots ok, and everything seems to be working ok, but I'm wondering about the difference here.

[root@localhost buck]# fdisk -l

Disk /dev/sda: 80.0 GB, 80000000000 bytes
255 heads, 63 sectors/track, 9726 cylinders, total 156250000 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000001

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1              63       64259       32098+   6  FAT16
/dev/sda2   *       64260   156232124    78083932+   7  HPFS/NTFS

Disk /dev/sdb: 320.1 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *          63    16370234     8185086   83  Linux
/dev/sdb2        16370235   625137344   304383555    5  Extended
/dev/sdb5        16370298    24547319     4088511   82  Linux swap / Solaris
/dev/sdb6        24547383   625137344   300294981   83  Linux
[root@localhost buck]#

[root@localhost buck]# cat /boot/grub/menu.lst
timeout 10
color black/cyan yellow/cyan
gfxmenu (hd1,0)/boot/gfxmenu
default 0

title linux
kernel (hd1,0)/boot/vmlinuz BOOT_IMAGE=linux root=UUID=eda7fcdf-0131-48f7-9c47-40ec0027fe72 quiet vmalloc=256M acpi=on resume=UUID=41ebc2ae-888e-497f-9de2-b7de288a1053 splash=silent vga=788
initrd (hd1,0)/boot/initrd.img

title Test Boot
kernel (hd1,0)/boot/vmlinuz BOOT_IMAGE=linux root=UUID=eda7fcdf-0131-48f7-9c47-40ec0027fe72 quiet vmalloc=256M acpi=on resume=UUID=41ebc2ae-888e-497f-9de2-b7de288a1053 splash=silent vga=788
initrd (hd1,0)/boot/initrd.img

title linux-nonfb
kernel (hd1,0)/boot/vmlinuz BOOT_IMAGE=linux-nonfb root=UUID=eda7fcdf-0131-48f7-9c47-40ec0027fe72 quiet vmalloc=256M acpi=on resume=UUID=41ebc2ae-888e-497f-9de2-b7de288a1053
initrd (hd1,0)/boot/initrd.img

title failsafe
kernel (hd1,0)/boot/vmlinuz BOOT_IMAGE=failsafe root=UUID=eda7fcdf-0131-48f7-9c47-40ec0027fe72 quiet nokmsboot failsafe vmalloc=256M acpi=on
initrd (hd1,0)/boot/initrd.img

title windows
root (hd0,0)
map (0x81) (0x80)
map (0x80) (0x81)
makeactive
chainloader +1

title memtest-4.20
kernel (hd1,0)/boot/memtest-4.20 BOOT_IMAGE=memtest-4.20
[root@localhost buck]#

[root@localhost buck]# cat /etc/fstab
# Entry for /dev/sdb1 :
UUID=eda7fcdf-0131-48f7-9c47-40ec0027fe72 / ext3 defaults 1 1
# Entry for /dev/sdb6 :
UUID=14a6d388-3ccc-48ad-9bf2-b5e78c5a13b2 /home ext3 defaults 1 2
none /proc proc defaults 0 0
# Entry for /dev/sdb5 :
UUID=41ebc2ae-888e-497f-9de2-b7de288a1053 swap swap defaults 0 0
none /dev/pts devpts defaults 0 0
[root@localhost buck]#

Would somebody mind explaining this for me.

Thanks
Batzilla

Dell Dimension 4500
PCLinuxOS 2012.08-KDE
Release 3.2.18-pclos2.bfs
KDE 4.8.3

Offline Bald Brick

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Re: Same partition named hdb and sdb. Is there a difference?
« Reply #1 on: October 08, 2012, 11:10:02 AM »
Just a couple of years ago only SCSI and SATA drives used to get the designation /dev/sdx while IDE drives where named /dev/hdx. I don't remember with which kernel this changed, but it was quite some time ago and today /dev/sdx is the normal designation for both SATA and IDE drives.  That Grub still expects you to use (hdn,m) is quite another matter.
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Offline Just17

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Re: Same partition named hdb and sdb. Is there a difference?
« Reply #2 on: October 08, 2012, 05:00:20 PM »
The move from   /dev/hd?  to /dev/sd? was some time ago as BB said.
These device designations are within the OS.

Grub (legacy) is its own small OS and counts disks and partitions differently .....  although they appear somewhat similar.

(hd0,0)  is the first HDD and first partition on that drive  ....  equivalent to  /dev/sda1  (old designation  /dev/hda1)
(hd0,3)  is the first drive and the fourth partition    .............  equivalent to  /dev/sda4
(hd1,0)  is the second drive and the first partition ..............  equivalent to  /dev/sdb1

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