ELF (Executable and Linkable Format) is a format for libraries and executables used across different architectures and operating systems. Saying Y here will enable your kernel to run ELF binaries and enlarge it by about 13 KB. ELF support under Linux has now all but replaced the traditional Linux a.out formats (QMAGIC and ZMAGIC) because it is portable (this does *not* mean that you will be able to run executables from different architectures or operating systems however) and makes building run-time libraries very easy. Many new executables are distributed solely in ELF format. You definitely want to say Y here. Information about ELF is contained in the ELF HOWTO available from <http://www.tldp.org/docs.html#howto>. If you find that after upgrading from Linux kernel 1.2 and saying Y here, you still can't run any ELF binaries (they just crash), then you'll have to install the newest ELF runtime libraries, including ld.so (check the file <file:Documentation/Changes> for location and latest version).
ELF FDPIC binaries are based on ELF, but allow the individual load segments of a binary to be located in memory independently of each other. This makes this format ideal for use in environments where no MMU is available as it still permits text segments to be shared, even if data segments are not. It is also possible to run FDPIC ELF binaries on MMU linux also.
ELF core dump files describe each memory mapping of the crashed process, and can contain or omit the memory contents of each one. The contents of an unmodified text mapping are omitted by default. For an unmodified text mapping of an ELF object, including just the first page of the file in a core dump makes it possible to identify the build ID bits in the file, without paying the i/o cost and disk space to dump all the text. However, versions of GDB before 6.7 are confused by ELF core dump files in this format. The core dump behavior can be controlled per process using the /proc/PID/coredump_filter pseudo-file; this setting is inherited. See Documentation/filesystems/proc.txt for details. This config option changes the default setting of coredump_filter seen at boot time. If unsure, say Y.
Support uClinux FLAT format binaries.
Support FLAT format compressed binaries
Support FLAT shared libraries
A.out (Assembler.OUTput) is a set of formats for libraries and executables used in the earliest versions of UNIX. Linux used the a.out formats QMAGIC and ZMAGIC until they were replaced with the ELF format. The conversion to ELF started in 1995. This option is primarily provided for historical interest and for the benefit of those who need to run binaries from that era. Most people should answer N here. If you think you may have occasional use for this format, enable module support above and answer M here to compile this support as a module called binfmt_aout. If any crucial components of your system (such as /sbin/init or /lib/ld.so) are still in a.out format, you will have to say Y here.
Say Y if you are using OSF/1 binaries (like Netscape and Acrobat) with v4 shared libraries freely available from Compaq. If you're going to use shared libraries from Tru64 version 5.0 or later, say N.
Say Y here if you want to be able to execute Linux/Intel ELF binaries just like native Alpha binaries on your Alpha machine. For this to work, you need to have the emulator /usr/bin/em86 in place. You can get the same functionality by saying N here and saying Y to "Kernel support for MISC binaries". You may answer M to compile the emulation support as a module and later load the module when you want to use a Linux/Intel binary. The module will be called binfmt_em86. If unsure, say Y.
SOM is a binary executable format inherited from HP/UX. Say Y here to be able to load and execute SOM binaries directly.
If you say Y here, it will be possible to plug wrapper-driven binary formats into the kernel. You will like this especially when you use programs that need an interpreter to run like Java, Python, .NET or Emacs-Lisp. It's also useful if you often run DOS executables under the Linux DOS emulator DOSEMU (read the DOSEMU-HOWTO, available from <http://www.tldp.org/docs.html#howto>). Once you have registered such a binary class with the kernel, you can start one of those programs simply by typing in its name at a shell prompt; Linux will automatically feed it to the correct interpreter. You can do other nice things, too. Read the file <file:Documentation/binfmt_misc.txt> to learn how to use this feature, <file:Documentation/java.txt> for information about how to include Java support. and <file:Documentation/mono.txt> for information about how to include Mono-based .NET support. To use binfmt_misc, you will need to mount it: mount binfmt_misc -t binfmt_misc /proc/sys/fs/binfmt_misc You may say M here for module support and later load the module when you have use for it; the module is called binfmt_misc. If you don't know what to answer at this point, say Y.