Free Knowledge Resources


Linux Manual Pages


Free Software * Books

Source Code

Free Media

Linux

blockdev(8)


NAME

   blockdev - call block device ioctls from the command line

SYNOPSIS

   blockdev [-q] [-v] command [command...] device [device...]
   blockdev --report [device...]

DESCRIPTION

   The  utility  blockdev  allows one to call block device ioctls from the
   command line.

OPTIONS

   -V     Print version and exit.

   -q     Be quiet.

   -v     Be verbose.

   --report
          Print a report for the specified device. It is possible to  give
          multiple  devices. If none is given, all devices which appear in
          /proc/partitions are shown. Note that the partition StartSec  is
          in 512-byte sectors.

COMMANDS

   It is possible to give multiple devices and multiple commands.

   --flushbufs
          Flush buffers.

   --getalignoff
          Get alignment offset.

   --getbsz
          Print blocksize in bytes.

   --getdiscardzeroes
          Get discard zeroes support status.

   --getfra
          Get filesystem readahead in 512-byte sectors.

   --getiomin
          Get minimum I/O size.

   --getioopt
          Get optimal I/O size.

   --getmaxsect
          Get max sectors per request

   --getpbsz
          Get physical block (sector) size.

   --getra
          Print readahead (in 512-byte sectors).

   --getro
          Get read-only. Print 1 if the device is read-only, 0 otherwise.

   --getsize64
          Print device size in bytes.

   --getsize
          Print  device  size (32-bit!) in sectors. Deprecated in favor of
          the --getsz option.

   --getss
          Print sector size in bytes -- usually 512.

   --getsz
          Get size in 512-byte sectors.

   --rereadpt
          Reread partition table

   --setbsz bytes
          Set blocksize. Note that the  block  size  is  specific  to  the
          current  file descriptor opening the block device, so the change
          of block size only persists for as  long  as  blockdev  has  the
          device open, and is lost once blockdev exits.

   --setfra sectors
          Set filesystem readahead (same like --setra on 2.6 kernels).

   --setra sectors
          Set readahead (in 512-byte sectors).

   --setro
          Set read-only.

   --setrw
          Set read-write.

AUTHOR

   blockdev was written by Andries E. Brouwer and rewritten by Karel Zak.

AVAILABILITY

   The blockdev command is part of the util-linux package and is available
   from ftp://ftp.kernel.org/pub/linux/utils/util-linux/.



Opportunity


Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.



Free Software


Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.

Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.



Free Books


The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.

Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.



Education


Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.

Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.


birds banner