LinuxQuestions.org
Latest LQ Deal: Linux Power User Bundle
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Newbie
User Name
Password
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!

Notices


Reply
  Search this Thread
Old 06-14-2014, 09:42 AM   #1
singh016
LQ Newbie
 
Registered: Jun 2014
Posts: 6

Rep: Reputation: Disabled
bs in dd


I was trying to make my pendrive bootable. For that I found that "dd" will work. But I am not able to understand what does "bs=4M" mean ? What does it do ?

Please help me out!!
 
Old 06-14-2014, 10:17 AM   #2
neilcpp
Member
 
Registered: Jul 2003
Location: England
Distribution: Debian Jessie, FreeBSD 10.1 anything *nix to get my fix
Posts: 329

Rep: Reputation: Disabled
Quote:
Originally Posted by singh016 View Post
I was trying to make my pendrive bootable. For that I found that "dd" will work. But I am not able to understand what does "bs=4M" mean ? What does it do ?

Please help me out!!
Well the 'dd' manual page says that 'bs means Bytes. Read and write BYTES bytes at a time (also see ibs=,obs=)'. I recommend you take a look at the manual page as a starting point.
 
Old 06-14-2014, 10:56 AM   #3
273
LQ Addict
 
Registered: Dec 2011
Location: UK
Distribution: Debian Sid AMD64, Raspbian Wheezy, various VMs
Posts: 5,990

Rep: Reputation: 1611Reputation: 1611Reputation: 1611Reputation: 1611Reputation: 1611Reputation: 1611Reputation: 1611Reputation: 1611Reputation: 1611Reputation: 1611Reputation: 1611
It stands, I believe, for "block size" and seems to be the amount of data read and/or written in one operation.
 
Old 06-14-2014, 12:07 PM   #4
metaschima
Senior Member
 
Registered: Dec 2013
Distribution: Slackware
Posts: 1,982

Rep: Reputation: 490Reputation: 490Reputation: 490Reputation: 490Reputation: 490
It is also important for the 'count=' option. You specify the count in terms of 'bs'. So 'bs=1M count=1000' would write 1000 M in 1M chunks.

Also, a higher 'bs' usually leads to better performance. From my benchmarks 'bs=4M' or 'bs=6M' work best depending on your processor cache size and other factors.

Last edited by metaschima; 06-14-2014 at 12:09 PM.
 
Old 06-14-2014, 12:35 PM   #5
singh016
LQ Newbie
 
Registered: Jun 2014
Posts: 6

Original Poster
Rep: Reputation: Disabled
Thank you guys !!
It was helpful !
 
  


Reply


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




All times are GMT -5. The time now is 01:07 AM.

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