by Roderick W. Smith, rodsmith@rodsbooks.com
-Originally written: 3/19/2012; last Web page update: 3/26/2012, referencing rEFInd 0.2.3
+Originally written: 3/19/2012; last Web page update: 4/5/2012, referencing rEFInd 0.2.4
I'm a technical writer and consultant specializing in Linux technologies. This Web page is provided free of charge and with no annoying outside ads; however, I did take time to prepare it, and Web hosting does cost money. If you find this Web page useful, please consider making a small donation to help keep this site up and running. Thanks!
@@ -103,7 +103,7 @@ href="mailto:rodsmith@rodsbooks.com">rodsmith@rodsbooks.comThe Linux EFI stub loader is a way to turn a Linux kernel into an EFI application. In a sense, the kernel becomes its own boot loader. This approach to booting Linux is very elegant in some ways, but as described on the page to which I just linked, it has its disadvantages, too. One challenge to booting in this way is that modern Linux installations typically require that the kernel be passed a number of options at boot time. These tell the kernel where the Linux root (/) filesystem is, where the initial RAM disk is, and so on. Without these options, Linux won't boot. These options are impossible for a generic boot loader to guess without a little help. For this reason, rEFIt, rEFInd's parent program, could not boot a Linux kernel with EFI stub support. rEFInd, however, goes a little further....
+The Linux EFI stub loader is a way to turn a Linux kernel into an EFI application. In a sense, the kernel becomes its own boot loader. This approach to booting Linux is very elegant in some ways, but as described on the page to which I just linked, it has its disadvantages, too. One challenge to booting in this way is that modern Linux installations typically require that the kernel be passed a number of options at boot time. These tell the kernel where the Linux root (/) filesystem is, where the initial RAM disk is, and so on. Without these options, Linux won't boot. These options are impossible for a generic boot loader to guess without a little help. It's possible to build a kernel with a default set of options, but this is rather limiting. Thus, rEFInd provides configuration options to help.
With all versions of rEFInd, you can create manual boot loader stanzas in the refind.conf file to identify a Linux kernel and to pass it all the options it needs. This approach is effective and flexible, but it requires editing a single configuration file. If a computer boots two different Linux distributions, and if both were to support rEFInd, problems might arise as each one tries to modify its own rEFInd configuration; or the one that controls rEFInd might set inappropriate options for another distribution. This is a problem that's been a minor annoyance for years under BIOS, since the same potential for poor configuration applies to LILO, GRUB Legacy, and GRUB 2 on BIOS. The most reliable solution there is to chainload one boot loader to another. The same solution is possible under EFI, but rEFInd offers another possibility.