Puppy Linux Discussion Forum

MustardMan · Joined: 15 May 2006 Posts: 21 Location: Australia

I am unsure as to whether this problem is a bug in Puppy, so I'll start by enquiring in this sub-forum...

I am using Puppy with Kernel 2.6.31.14. I believe it is Cielo but I can't be sure as 'system information' does not tell me. I am not at the level of rebuilding Puppy to suit my own needs, so i am using an out-of-the-box download that does most things for me. I mainly run this on an EeePC (ASUS) as it was the only one I found that actually worked (details at the end for the interested).

To the problem...
I have a 3TB Western Digital (elements) hard disk. However, when I connect it to Puppy it reports a size of 746.5GB, and refuses to mount it.
At first I thought it might be the EeePC, so I booted Puppy (same version) on a desktop machine, and the same thing.
The disk is fine, as I can read/write it using both windows and ubuntu. The full capacity is reported and available.

Details of my EeePC install. The 'Cielo' version of Puppy was the only one I found that
- the sound in the EeePC worked
- it had libreoffice
- it had a VLC player install that worked
It has problems though
- the WiFi can't do AES connections. I don't use it for internet, so it is something I have not put a great deal of effort into solving.
- I would like a 'second monitor' on the external VGA port. I have to boot windoze to use this.

Cheers,
MM.

Flash · Posted: Fri 07 Dec 2012, 22:33 Post subject:

This probably has nothing to do with the problem, but what filesystem is the disk formatted?

technosaurus · Joined: 18 May 2008 Posts: 3843

verify the bios supports it before you get too far banging your head

MustardMan · Joined: 15 May 2006 Posts: 21 Location: Australia

OK, done a bit more thinking about this during the holidays...

If I (dual) boot the computer using Win XP, the disk is fully accessible, and the correct size is reported.

The disk is formatted NTFS: Puppy does support NTFS for all my other disks, perhaps there is a problem with large NTFS volumes?

When I ask Puppy to mount the drive, it tells me it can't, and prompts again. When I hover over the icon, it reports a disk size of about 750GB. Interestingly this is one of the 'newer' type drives with the so called 'advanced' format : the sector size is 4096 bytes rather than the usual 512 bytes.

More interestingly, if I multiply the sector size difference (8x) by the size that Puppy reports the drive size to be, I get double the actual size.

IE: 8 x 750 GB ~ 6 TB (3 TB drive).

It is probably important that I add this is an external USB attached drive (I forgot in my original post), as apparently there is some issue with internal 3TB (and larger) drives - predominantly with Windoze though.

Is Puppy OK with 4k sectors, or is there some issue?

Ubuntu is OK with this drive, so it is unlikely to be a Kernel thing (unless my Puppy is extremely out of date).

Any ideas?

Cheers,
MM.

jamesbond · Joined: 26 Feb 2007 Posts: 1531 Location: The Blue Marble

you need a puppy with a kernel compiled with support for GPT partition.

pemasu · Joined: 08 Jul 2009 Posts: 5165 Location: Finland

What is the DOTconfig option called which enables gpt support ?

Flash · Posted: Thu 27 Dec 2012, 10:50 Post subject:

pemasu · Joined: 08 Jul 2009 Posts: 5165 Location: Finland

Thanks Flash. I found a good page about gpt and linux. It needs gpt enabled kernel and also boot loader which supports gpt. Grub2 supports it natively. Grub legacy needs patch for supporting it.

http://www.ibm.com/developerworks/linux/library/l-gpt/

And the answer to my question:

JustGreg · Joined: 24 May 2005 Posts: 651 Location: Connecticut USA

I have been trying to UEFI (Unified Electronic Firmware Interface) with Puppy. In the process. I did learn something about a GPT disk (required by UEFI). The older BIOS used for hard disks, the hard disk geometry (cylinders and heads) approach with sectors of 512 bytes in the partition table. The newer GPT approach uses sectors of 4096 bytes (8 times the old 512 byte sector). Additionally, all GPT partitions must end on a 1 Megabyte boundary. This can be a source of problems (unused or mapped sectors) with a mix of file system and partitions. This sounds like the source of the problem.

Puppy maybe mounting the disk with partition table information and not the GPT information. I have a similar ASUS EeePc with XP. I do know the disk is partition with a GPT approach. However, it is much smaller than yours.

Unfortunately, like Flash, I have never done any kernel work. I do not have a clue on what needs to be done. But, maybe the experts can use this.

Looks like Pemasu and I will composing posts at the same time and he won!

MustardMan · Joined: 15 May 2006 Posts: 21 Location: Australia

Without knowing too much about EFI partitions (I gave away keeping up with computer hardware long ago - no time!), I was under the impression a GPT was not essential to define a disk of this size...

Whether a disk is bootable or not, the MBR (first track, first sector) contains data about the geometry of the disk. Of course, much of it is no longer physical, it is logical (CHS : tracks, heads...) but some of it does relate to the real device (sector size, cluster size...).

So, in this 'table', one of the entries is 'bytes per sector' (a word at 0B). It always used to contain 512 (00 02), but for the 3TB disk I refer to it contains 4096 (00 10).

Does the linux kernel not use this information? Does it really need to refer to a GPT to get the size of a disk right?

James C · Joined: 26 Mar 2009 Posts: 4737 Location: Kentucky

Might contain some useful info...
http://www.linux-mag.com/id/7897/

and
http://www.ibm.com/developerworks/linux/library/l-gpt/

jamesbond · Joined: 26 Feb 2007 Posts: 1531 Location: The Blue Marble