/dev/sda1 or /dev/hda1

allele · 06-20-2009, 09:59 AM

What is the difference between /dev/sda1 and /dev/hda1? Do they usually both refer to the first partition on the first disk? If so, why are there two places for what seems to be the same thing?

rsciw · 06-20-2009, 10:05 AM

Think that depends on how your distro addresses them, might be drivers, not too sure.

My debian addresses my HD as /dev/sda
My centOS workstation addresses my HD as /dev/hda, while in the same time addressing my USB stick as /dev/sda.

In the case you're not sure what yours are addressed as, run in CLI

dmesg | grep sda
or
dmesg | grep hda

or just
dmesg

for full output

jdkaye · 06-20-2009, 10:26 AM

Quote:

Originally Posted by allele

What is the difference between /dev/sda1 and /dev/hda1? Do they usually both refer to the first partition on the first disk? If so, why are there two places for what seems to be the same thing?

In my case I have both. /dev/hda1 is my hard drive and /dev/sda1 is my usb 400GB external storage.
I thought sd... meant scsi but I guess I'm wrong.
cheers,
jdk

colucix · 06-20-2009, 10:32 AM

Quote:

Originally Posted by jdkaye

I thought sd... meant scsi but I guess I'm wrong

Correct. In the good ol' days before Serial ATA, hda was the first IDE disk, sda was the first SCSI disk. USB disks and many other interfaces today are addressed as SCSI disks from the kernel.

michaelk · 06-20-2009, 10:41 AM

It depends. For information what distribution / version and kernel are you running. /dev/hdx used to refer to PATA(IDE) drives and all drives that use the SCSI subsystem (SCSI, USB, Firewire, SATA) have a device ID of /dev/sdx. With kernels that are configured to use libata all drives now have a /dev/sdx device ID.

onebuck · 06-20-2009, 11:47 AM

Hi,

'Persistent block device naming' will make things transparent.

The 'libATA FAQ' will aid you to understand things along with why to use persistent naming (above link).

It does depend on the level of kernel you happen to be using with the distribution. Most current distro support 'libATA'.

These links and others can be found at 'Slackware-Links'. More than just Slackware® links!