Comments on: Adding a simple progress bar to dd http://www.lancealbertson.com/2009/04/adding-a-simple-progress-bar-to-dd/ Musings of a geek, jazz performer, and an OSUOSL sysadmin Tue, 24 May 2011 16:15:58 +0100 hourly 1 http://wordpress.org/?v=3.2.1 By: Eli http://www.lancealbertson.com/2009/04/adding-a-simple-progress-bar-to-dd/comment-page-1/#comment-127 Eli Tue, 23 Nov 2010 19:57:05 +0000 http://test.lancealbertson.com/?p=93#comment-127 @KK I think what you mean is to do is (as root): dd if=/dev/zero of=/dev/sd(x) bs=512 count=1 where sd(x) is your hard drive, bs is the the block size, and count is the number of times the block is written to disk. The command above writes a 512 byte block of zeros to the beginning of your drive, destroying the Master Boot Record (mbr is always the first 512 bytes on a drive). This effectively blanks the drive albiet in a non-secure manner (ie the most data on the drive will be retiervable). DD'ing the buffer or cache of a drive will only clear data used by a drives "read-ahead" feature, which it uses cached data from your disk for performance reasons. If DD'ing your drive buffer/cache blanked your drive, the the following command would not be safe to use to gauge disk performance, as it flushes the disk buffer/cache: hdparm -tT /dev/sd(x). I'm not sure it's even possible to write bits to the drive cache/buffer via the DD command. @KK

I think what you mean is to do is (as root):

dd if=/dev/zero of=/dev/sd(x) bs=512 count=1

where sd(x) is your hard drive, bs is the the block size, and count is the number of times the block is written to disk.

The command above writes a 512 byte block of zeros to the beginning of your drive, destroying the Master Boot Record (mbr is always the first 512 bytes on a drive). This effectively blanks the drive albiet in a non-secure manner (ie the most data on the drive will be retiervable).

DD’ing the buffer or cache of a drive will only clear data used by a drives “read-ahead” feature, which it uses cached data from your disk for performance reasons. If DD’ing your drive buffer/cache blanked your drive, the the following command would not be safe to use to gauge disk performance, as it flushes the disk buffer/cache:

hdparm -tT /dev/sd(x).

I’m not sure it’s even possible to write bits to the drive cache/buffer via the DD command.

]]> By: Bud http://www.lancealbertson.com/2009/04/adding-a-simple-progress-bar-to-dd/comment-page-1/#comment-96 Bud Mon, 17 May 2010 19:47:58 +0000 http://test.lancealbertson.com/?p=93#comment-96 You can also use pv (Pipe Viewer)[1] to do this kind of stuff. [1] http://packages.gentoo.org/package/sys-apps/pv You can also use pv (Pipe Viewer)[1] to do this kind of stuff.

[1] http://packages.gentoo.org/package/sys-apps/pv

]]> By: Techie Talks http://www.lancealbertson.com/2009/04/adding-a-simple-progress-bar-to-dd/comment-page-1/#comment-92 Techie Talks Sat, 19 Dec 2009 14:55:39 +0000 http://test.lancealbertson.com/?p=93#comment-92 Cool progress bar. It's so simple and I love the effect its like having linux online. Cool progress bar. It’s so simple and I love the effect its like having linux online.

]]> By: kk http://www.lancealbertson.com/2009/04/adding-a-simple-progress-bar-to-dd/comment-page-1/#comment-91 kk Sat, 05 Dec 2009 10:23:23 +0000 http://test.lancealbertson.com/?p=93#comment-91 Just a tip about zeroing drives with dd : use bs="buffer size ofthe driver" for the speedy erase. You can try several dd, letting it go about 2 min then ctrl-c and compare the output. So: dd if=/dev/null of=/dev/"sdX" bs="buffer size of the harddisk" you can see the buffer size with hdparm -i /dev/"sdX" sdX here is the drivename you have to substitte can be sda sdb ... BE CAREFUL!!! Just a tip about zeroing drives with dd :
use bs=”buffer size ofthe driver” for the speedy erase.
You can try several dd, letting it go about 2 min then ctrl-c
and compare the output. So:
dd if=/dev/null of=/dev/”sdX” bs=”buffer size of the harddisk”

you can see the buffer size with hdparm -i /dev/”sdX”

sdX here is the drivename you have to substitte can be sda sdb …

BE CAREFUL!!!

]]> By: Hal Pomeranz http://www.lancealbertson.com/2009/04/adding-a-simple-progress-bar-to-dd/comment-page-1/#comment-88 Hal Pomeranz Thu, 21 May 2009 03:35:27 +0000 http://test.lancealbertson.com/?p=93#comment-88 There's also dcfldd, which includes progress-bar functionality built-in (albeit a ASCII art progress bar). It might be interesting running some timing tests to see how much overhead is involved in displaying the progress bar via these various methods as opposed to just doing the dd without any status updates. There’s also dcfldd, which includes progress-bar functionality built-in (albeit a ASCII art progress bar).

It might be interesting running some timing tests to see how much overhead is involved in displaying the progress bar via these various methods as opposed to just doing the dd without any status updates.

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