Review your favorite Linux distribution.
Go Back > Forums > Linux Forums > Linux - Newbie
User Name
Linux - Newbie This Linux forum is for members that are new to Linux.
Just starting out and have a question? If it is not in the man pages or the how-to's this is the place!


  Search this Thread
Old 01-07-2007, 08:40 AM   #16
Registered: Aug 2002
Posts: 21,015

Rep: Reputation: 3877Reputation: 3877Reputation: 3877Reputation: 3877Reputation: 3877Reputation: 3877Reputation: 3877Reputation: 3877Reputation: 3877Reputation: 3877Reputation: 3877

You should reboot the computer.
Old 01-07-2007, 11:33 AM   #17
Senior Member
Registered: Sep 2005
Location: Newcastle upon Tyne UK
Distribution: Any free distro.
Posts: 3,398
Blog Entries: 1

Rep: Reputation: 113Reputation: 113
The reason I suggested using cfdisk program because a user cannot create an extended partition in cfdisk. Whenever the first logical partition is created then the extended partition will be formed as a by-product. An extended partition has no storage unit inide but just acts as an envelope for all the logical partitions inside.

Basically a hard disk can have a mximum of 4 primary partition. Each has the the hard disk address of the begining and fisnishing point of the partition. If a user want more than 4 partition then one of the 4 primaries must be given up to turn into an extended partition. This is done by altering the partition type but the begining and finishing points are defined exactly like a primary. Inside the exetnded partition one logical partition must carries the address for the next one up and all of them must be in a continuous chain, with the end link matching the finishing point specified in the extended partition. A logical partition at the middle if deleted will have the space "dead" and Linux will automatically shift everything up. This phenomanon can be seen in cfdisk program.

It is therefore not possible to format an extended partition and usch a misadventure could not have happened if cfdisk program was used.

Michaelk's recommendation is a good practice that any alteration to the partition table can only be secured after a reboot so that the operating system can use the new confiuration.

Last edited by saikee; 01-07-2007 at 11:41 AM.
Old 01-08-2007, 09:31 AM   #18
Registered: Apr 2006
Posts: 36

Original Poster
Rep: Reputation: 15
I cannnot find "cfdisk" command under my Red Hat Linux...where is it?

Data Sheet
Old 01-08-2007, 10:11 AM   #19
Senior Member
Registered: Sep 2005
Location: Newcastle upon Tyne UK
Distribution: Any free distro.
Posts: 3,398
Blog Entries: 1

Rep: Reputation: 113Reputation: 113
Ah yes the Red Hat family is the odd one out that uses sfdisk instead of cfdisk. It isn't the same thing. Try cfdisk on a Live CD.

I think both fdisk and sfdisk permit a user to declare an extended partition and assume the user knows to to use it.

The major advantage of cfdisk is you can see the partition names and the relative positions in the hard disk in a tabulated format. This is important to a user who creates a logical partition first and then a primary second. This is because the first logical partition must be hda5 (or sda5 in a Sata) and the first available primary partition hda1 would be converted to the extended partition necessary if any logical partition is formed, without the user intervention. The actual first primary partition created must take the name hda2 and follow immediately behind hda5 in the hard disk.

The above may sound crazy but that is exactly the partitions would be arranged in the PC hard disk if a user wants one logical partition first and then a primary partition second.
Old 01-08-2007, 04:13 PM   #20
LQ Veteran
Registered: Nov 2005
Location: Annapolis, MD
Distribution: Mint
Posts: 17,805

Rep: Reputation: 742Reputation: 742Reputation: 742Reputation: 742Reputation: 742Reputation: 742Reputation: 742
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table.
The new table will be used at the next reboot.
Syncing disks.

and when I do # mkfs.ext3 /dev/hda4
it says "could not stat /dev/hda4 --- no such file or directory
While the partition table has been updated, the kernel still works on the old one. Thus the refusal to create a new filesystem. When you re-boot, it should all work.

I use "raw device" to mean anything accessible thru a low-level utility such as dd---without the benefit of any filesystem structure. Whether or not a disk has been partitioned or had a filessytem installed it always accessible as a raw device.


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Do we need partition table for RAW device masand Linux - Hardware 1 02-22-2006 07:52 PM
Cannot open master raw device MDColson Mandriva 1 12-31-2004 02:55 PM
ASE master db on raw device? Andrastus Linux - Enterprise 0 12-13-2004 05:20 AM
block device raw access rvilarl Programming 0 10-24-2004 01:53 PM
SuSE: How to create raw device stjacqd Linux - General 3 07-22-2004 07:29 PM > Forums > Linux Forums > Linux - Newbie

All times are GMT -5. The time now is 12:16 AM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Open Source Consulting | Domain Registration