<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML ><HEAD ><TITLE >Persistent Data</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK REL="HOME" TITLE="Linux Loadable Kernel Module HOWTO" HREF="index.html"><LINK REL="PREVIOUS" TITLE="About Module Parameters" HREF="parm.html"><LINK REL="NEXT" TITLE="Technical Details" HREF="x627.html"></HEAD ><BODY CLASS="SECT1" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >Linux Loadable Kernel Module HOWTO</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="parm.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="x627.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="AEN615" ></A >9. Persistent Data</H1 ><P >Some LKMs are set up to retain information from one load to the next. This is called persistent data. When you remove one of these LKMs with <B CLASS="COMMAND" >rmmod</B >, <B CLASS="COMMAND" >rmmod</B > extracts certain values from the LKM's working storage and stores them in a file. When you next insert the LKM with <B CLASS="COMMAND" >insmod</B >, <B CLASS="COMMAND" >insmod</B > reads the persistent data from the file and inserts it into the LKM.</P ><P >See the <TT CLASS="PARAMETER" ><I >--persist</I ></TT > option on <B CLASS="COMMAND" >insmod</B > and <B CLASS="COMMAND" >rmmod</B >.</P ><P >Persistent data was introduced in November 2000.</P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="parm.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="x627.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >About Module Parameters</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" > </TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Technical Details</TD ></TR ></TABLE ></DIV ></BODY ></HTML >