Re: [PLUG] stick drive that mounts as /dev/sda (or sdb....)

root@noname:~# fdisk -l /dev/sda

Disk /dev/sda: 4043 MB, 4043309056 bytes
125 heads, 62 sectors/track, 1018 cylinders
Units = cylinders of 7750 * 512 = 3968000 bytes
Disk identifier: 0x6f20736b

This doesn't look like a partition table
Probably you selected the wrong device.

   Device Boot      Start         End      Blocks   Id System
/dev/sda1   ?      100405      247697   570754815+ 72 Unknown
Partition 1 has different physical/logical beginnings (non-Linux?):
     phys=(357, 116, 40) logical=(100404, 79, 11)
Partition 1 has different physical/logical endings:
     phys=(357, 32, 45) logical=(247696, 24, 51)
Partition 1 does not end on cylinder boundary.
/dev/sda2   ?       21767      271577   968014120   65 Novell Netware 386
Partition 2 has different physical/logical beginnings (non-Linux?):
     phys=(288, 115, 43) logical=(21766, 48, 47)
Partition 2 has different physical/logical endings:
     phys=(367, 114, 50) logical=(271576, 60, 42)
Partition 2 does not end on cylinder boundary.
/dev/sda3   ?      241276      491086   968014096   79 Unknown
Partition 3 has different physical/logical beginnings (non-Linux?):
     phys=(366, 32, 33) logical=(241275, 3, 30)
Partition 3 has different physical/logical endings:
     phys=(357, 32, 43) logical=(491085, 14, 39)
Partition 3 does not end on cylinder boundary.
/dev/sda4   ?      372346      372354       27749+   d Unknown
Partition 4 has different physical/logical beginnings (non-Linux?):
     phys=(372, 97, 50) logical=(372345, 119, 25)
Partition 4 has different physical/logical endings:
     phys=(0, 10, 0) logical=(372353, 14, 33)
Partition 4 does not end on cylinder boundary.

Partition table entries are not in disk order

From: Michael Lazin <microlaser@gmail.com>
To: Philadelphia Linux User's Group Discussion List <plug@lists.phillylinux.org>
Sent: Thursday, August 13, 2009 1:07:00 PM
Subject: Re: [PLUG] stick drive that mounts as /dev/sda (or sdb....)

I don't think you can have a drive without a partition table. Most thumb drives have 1 or 2 partitions on it by default. There are a lot of them that come with a separate partition with some proprietary junk you probably don't want. What does "fdisk -l" output?

On Thu, Aug 13, 2009 at 12:40 PM, Edmond Rodriguez <erodrig_97@yahoo.com> wrote:
Is there a reason why mounting a formatted usb stick drive with no partition table would be a bad practice?

During a meeting about two months ago, I mentioned I had a 4GB usb stick drive that I could only mount to /dev/sda (or b or c etc..). I eventually learned I could mount it to /dev/sda (instead of sda1, or sda2 etc..)

The drive mounts fine and I tried putting some large files in it, which also worked fine.

A comment was made at the meeting that the stick drive had no partition table, which was true. Though fdisk shows me a partition table, the data looks random, and a warning is printed that the device probably has no partition table.

Someone was also surprised I could successfully mount this drive to /dev/sda. I have googled and seen a few sites discussing doing the same thing.

All seems well. but is there a reason this is NOT a good practice (using the drive with no partition table)?

Here is some log information and a "df" command below:

Aug 13 12:23:28 localhost kernel: usb 1-1: Manufacturer: USBest Technology
Aug 13 12:23:28 localhost kernel: usb 1-1: SerialNumber: 080501118ed735
Aug 13 12:23:33 localhost kernel: scsi 7:0:0:0: Direct-Access Ut165 USB2FlashStorage 0.00 PQ: 0 ANSI: 2
Aug 13 12:23:33 localhost kernel: sd 7:0:0:0: [sda] 7897088 512-byte hardware sectors (4043 MB)
Aug 13 12:23:33 localhost kernel: sd 7:0:0:0: [sda] Write Protect is off
Aug 13 12:23:33 localhost kernel: sd 7:0:0:0: [sda] 7897088 512-byte hardware sectors (4043 MB)
Aug 13 12:23:33 localhost kernel: sd 7:0:0:0: [sda] Write Protect is off
Aug 13 12:23:33 localhost kernel: sda:
Aug 13 12:23:33 localhost kernel: sd 7:0:0:0: [sda] Attached SCSI removable disk
Aug 13 12:23:33 localhost kernel: sd 7:0:0:0: Attached scsi generic sg0 type 0

root@noname:/home/edmondrod# df -T /mnt/sda
Filesystem Type 1K-blocks Used Available Use% Mounted on
/dev/sda vfat 3940828 4 3940824 1% /mnt/sda
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--
Michael Lazin

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