[SOLVED] What is this mysterious extra HDD?

grumpyskeptic · 01-09-2024, 10:54 AM

Using Linux Mint Cinnamon Victoria and an OEM "B75 Ver 1.41" motherboard in an OEM case with an AMI "4.6.5 09/01/2021" BIOS.

My old Dell computer's motherboard stopped working so I bought a new OEM computer, as described above. I replaced the Windows10 OS with Linux Mint Cinnamon Victoria.

My old Dell computer had two hard drives, and I have put them in the new OEM computer, meaning it now has three HDDs. I have deleted the old Linux Mint operating system from the old Dell HDD, leaving just the folder with my files in it.

But the file manager appears to show that there is a mysterious extra very small HDD.

The unexpected fourth HDD has a capacity of 537 MB - mega-bytes not GB. The details copied from Properties are:

"Name: 1637-A672
Type: Folder (inode/directory)
Contents: nothing
Size: 0 bytes
Location: /media/username
Volume: 537 MB Volume
Modified: unknown
Free space: 535.8*MB"

"Filesystem type: msdos"

This small HDD can be mounted and unmounted independently of the other two extra HDD.

What is it? Where is it?

michaelk · 01-09-2024, 11:07 AM

Drive or partition? What is its device ID?

The label i.e. 1637-A672 would indicate a FAT filesystem and the size could be indicative of an empty EFI partition.

mrmazda · 01-09-2024, 12:28 PM

OEM PCs often have built-in media readers. You could have one with a small inserted memory card with FAT filesystem and not even notice without looking for such. If you mount the mystery device and run tree command on its mount point, what is its input/output?

frankbell · 01-09-2024, 08:16 PM

What is the output of this command?

Code:

fdisk -l

grumpyskeptic · 01-10-2024, 05:35 AM

"Drive or partition?"

Don't know, no idea.

"What is its device ID?"

The internet tells me that device IDs are obtained by typing "xinput list" in a terminal. With only tthe mystery HDD mounted, this is what I got, but it does not seem to mention any HDD.

Code:

xinput list
⎡ Virtual core pointer                    	id=2	[master pointer  (3)]
⎜   ↳ Virtual core XTEST pointer              	id=4	[slave  pointer  (2)]
⎜   ↳  USB OPTICAL MOUSE                      	id=8	[slave  pointer  (2)]
⎜   ↳ SEM USB Keyboard Consumer Control       	id=10	[slave  pointer  (2)]
⎣ Virtual core keyboard                   	id=3	[master keyboard (2)]
    ↳ Virtual core XTEST keyboard             	id=5	[slave  keyboard (3)]
    ↳ Power Button                            	id=6	[slave  keyboard (3)]
    ↳ Video Bus                               	id=7	[slave  keyboard (3)]
    ↳ SEM USB Keyboard                        	id=9	[slave  keyboard (3)]
    ↳ SEM USB Keyboard System Control         	id=11	[slave  keyboard (3)]
    ↳ SEM USB Keyboard Consumer Control       	id=12	[slave  keyboard (3)]

"If you mount the mystery device and run tree command on its mount point, what is its input/output?"

I know how to mount the mystery HDD by clicking on it in ther file manager, but please explain how to do the other things.

"What is the output of this command?"

Even with the mystery HDD mounted, this is the result:

Code:

fdisk -l
fdisk: cannot open /dev/sda: Permission denied
fdisk: cannot open /dev/sdb: Permission denied
fdisk: cannot open /dev/sdc: Permission denied

Thanks.

hazel · 01-10-2024, 05:59 AM

Quote:

Originally Posted by grumpyskeptic

The internet tells me that device IDs are obtained by typing "xinput list" in a terminal.

No, that's input devices. Disk devices are best obtained using:

Code:

sudo /sbin/fdisk -l

As you have already noticed, the fdisk command needs root access, although the error messages you received are also informative. Clearly you have 3 partitions on your hard drive. fdisk will show you their size and type. But I am virtually certain already that the small partition is your EFI system partition because these are typically sized in MB and not GB.

Any new motherboard will have a UEFI and not a BIOS. UEFIs can emulate a traditional BIOS and boot from the mbr but natively they boot from files installed on the ESP. The filetype of the ESP is always vfat and you should be able to mount it on /boot/efi and look at its contents. Probably you will find a grub.efi file and your kernel and initrd, also a BOOT directory containing boot files for Windows

IsaacKuo · 01-10-2024, 06:01 AM

xinput only applies to input devices for X, like mouse and keyboard.

You need to run "fdisk" as root to have the necessary permissions. On Mint, a way to log in as root is with:

Code:

sudo su -

So, you could type in these commands:

Code:

sudo su -
fdisk -l
exit

mrmazda · 01-10-2024, 04:31 PM

Quote:

Originally Posted by grumpyskeptic

Quote:

"If you mount the mystery device and run tree command on its mount point, what is its input/output?"

I know how to mount the mystery HDD by clicking on it in ther file manager, but please explain how to do the other things.

Open a terminal emulator window
type tree
type a space
copy the name of the mount point from the file manager
paste it into the terminal window
press <RETURN>
copy the content of the terminal window and paste it here within a pair of code tags

Example output correctly pasted here within code tags:

Code:

> tree media/15.5-DVD
media/15.5-DVD
└── EFI
    └── BOOT
        ├── bootx64.efi
        ├── grub.cfg
        ├── grub.efi
        ├── locale
        │** └── en.mo
        └── MokManager.efi

3 directories, 5 files
>

grumpyskeptic · 01-11-2024, 06:46 AM

Quote:

Originally Posted by hazel

No, that's input devices. Disk devices are best obtained using:

Code:

sudo /sbin/fdisk -l

Running that command with all HDD, including the mystery HDD, mounted -

Code:

sudo /sbin/fdisk -l
[sudo] password for username:              
Disk /dev/sda: 931.51 GiB, 1000204886016 bytes, 1953525168 sectors
Disk model: ST31000524AS    
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 7D462EA4-BD89-47E1-9AB7-51734DCE0BBD

Device       Start        End    Sectors  Size Type
/dev/sda1     2048       4095       2048    1M BIOS boot
/dev/sda2     4096    1054719    1050624  513M EFI System
/dev/sda3  1054720 1953523711 1952468992  931G Linux filesystem


Disk /dev/sdb: 931.51 GiB, 1000204886016 bytes, 1953525168 sectors
Disk model: TOSHIBA DT01ACA1
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: dos
Disk identifier: 0xce7ace7a

Device     Boot Start        End    Sectors   Size Id Type
/dev/sdb1  *       63 1953503999 1953503937 931.5G  7 HPFS/NTFS/exFAT

Partition 1 does not start on physical sector boundary.


Disk /dev/sdc: 465.76 GiB, 500107862016 bytes, 976773168 sectors
Disk model: SAMSUNG HD501LJ 
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xc7a29918

Device     Boot   Start       End   Sectors   Size Id Type
/dev/sdc1  *       2048   1050623   1048576   512M  b W95 FAT32
/dev/sdc2       1052670 976771071 975718402 465.3G  5 Extended
/dev/sdc5       1052672 976771071 975718400 465.3G 83 Linux

"Partition 1 does not start on physical sector boundary." is in red.

grumpyskeptic · 01-11-2024, 06:51 AM

Quote:

Originally Posted by IsaacKuo

xinput only applies to input devices for X, like mouse and keyboard.

You need to run "fdisk" as root to have the necessary permissions. On Mint, a way to log in as root is with:

Code:

sudo su -

So, you could type in these commands:

Code:

sudo su -
fdisk -l
exit

Thanks, got same results as above.

grumpyskeptic · 01-11-2024, 06:54 AM

Quote:

Originally Posted by mrmazda

[list=1][*]Open a terminal emulator window[*]type tree[*]type a space[*]copy the name of the mount point from the file manager[*]paste it into the terminal window[*]press <RETURN>
....

I typed tree in the terminal but got -

Code:

Command 'tree' not found, but can be installed with:
sudo apt install tree

hazel · 01-11-2024, 07:17 AM

Quote:

Originally Posted by grumpyskeptic

Disklabel type: gpt
Disk identifier: 7D462EA4-BD89-47E1-9AB7-51734DCE0BBD

Device Start End Sectors Size Type
/dev/sda1 2048 4095 2048 1M BIOS boot
/dev/sda2 4096 1054719 1050624 513M EFI System
/dev/sda3 1054720 1953523711 1952468992 931G Linux filesystem

So this hard drive has been set up to boot in both ways. The initial BIOS boot partition is for a legacy boot in which GRUB is installed to the mbr. Actually only a stub of GRUB would go in there as there's not much space. The overflow goes onto that BIOS boot partition. On an old-fashioned DOS disk, it would go into the gap between the mbr and the first partition, but a gpt disk doesn't have that space, so you need a special partition instead. The second partition is your EFI system partition for a native UEFI boot. If you installed GRUB there rather than to the whole drive, it would appear as a normal file called grub.efi. And the third one is presumably your root partition.

Quote:

Disk /dev/sdb: 931.51 GiB, 1000204886016 bytes, 1953525168 sectors
Disklabel type: dos
Disk identifier: 0xce7ace7a

Device Boot Start End Sectors Size Id Type
/dev/sdb1 * 63 1953503999 1953503937 931.5G 7 HPFS/NTFS/exFAT

That's some kind of Windows data drive.

Quote:

Disk /dev/sdc: 465.76 GiB, 500107862016 bytes, 976773168 sectors
Disklabel type: dos
Disk identifier: 0xc7a29918

Device Boot Start End Sectors Size Id Type
/dev/sdc1 * 2048 1050623 1048576 512M b W95 FAT32
/dev/sdc2 1052670 976771071 975718402 465.3G 5 Extended
/dev/sdc5 1052672 976771071 975718400 465.3G 83 Linux

Old-fashioned DOS disk which seems to be dual-booting Windows-95 and Linux.

michaelk · 01-11-2024, 08:06 AM

The output of the lsblk command should show filesystem type, UUID and mount point so hopefully you can see the one that is the mystery drive:
lsblk -f

It may be /dev/sdc1 being automatically mounted but I don't see any partition that is 537MB.

IsaacKuo · 01-11-2024, 08:37 AM

Quote:

Originally Posted by michaelk

The output of the lsblk command should show filesystem type, UUID and mount point so hopefully you can see the one that is the mystery drive:
lsblk -f

It may be /dev/sdc1 being automatically mounted but I don't see any partition that is 537MB.

It's probably a friction between two different definitions of MB - 1,000,000 bytes vs 1,048,576 bytes.

The size of /dev/sdc1 is 1048576*512 = 536,870,912 bytes, which might round up to 537*1,000,000.

The size of /dev/sda2 (the EFI partition) is 1050624*512 = 537,919,488 bytes, which might round down to 537*1,000,000.

Either one might show up as "537MB" depending on which direction it rounds (up or down).

IsaacKuo · 01-11-2024, 08:39 AM

Oh one thing that's not obvious to the OP - "fdisk -l" ignores whether or not any of these partitions are mounted.

If you want to know which partitions are mounted, you can use "more /etc/mtab"