CONFIG_SMP
  This enables support for systems with more than one CPU. If you have
  a system with only one CPU, like most personal computers, say N. If
  you have a system with more than one CPU, say Y.

  If you say N here, the kernel will run on single and multiprocessor
  machines, but will use only one CPU of a multiprocessor machine. If
  you say Y here, the kernel will run on many, but not all,
  singleprocessor machines. On a singleprocessor machine, the kernel
  will run faster if you say N here.

  Note that if you say Y here and choose architecture "586" or
  "Pentium" under "Processor family", the kernel will not work on 486
  architectures. Similarly, multiprocessor kernels for the "PPro"
  architecture may not work on all Pentium based boards.

  People using multiprocessor machines who say Y here should also say
  Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
  Management" code will be disabled if you say Y here.

  See also the <file:Documentation/smp.tex>,
  <file:Documentation/smp.txt>, <file:Documentation/i386/IO-APIC.txt>,
  <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
  <http://www.linuxdoc.org/docs.html#howto>.

  If you don't know what to do here, say N.

CONFIG_IA64
  The Itanium is Intel's 64-bit successor to the 32-bit X86 line.  As
  of early 2001 it is not yet in widespread production use.  The Linux
  IA-64 project has a home page at <http://www.linuxia64.org/>.

CONFIG_IDE
  If you say Y here, your kernel will be able to manage low cost mass
  storage units such as ATA/(E)IDE and ATAPI units. The most common
  cases are IDE hard drives and ATAPI CD-ROM drives.

  If your system is pure SCSI and doesn't use these interfaces, you
  can say N here.

  Integrated Disk Electronics (IDE aka ATA-1) is a connecting standard
  for mass storage units such as hard disks. It was designed by
  Western Digital and Compaq Computer in 1984. It was then named
  ST506. Quite a number of disks use the IDE interface.

  AT Attachment (ATA) is the superset of the IDE specifications.
  ST506 was also called ATA-1.

  Fast-IDE is ATA-2 (also named Fast ATA), Enhanced IDE (EIDE) is
  ATA-3. It provides support for larger disks (up to 8.4GB by means of
  the LBA standard), more disks (4 instead of 2) and for other mass
  storage units such as tapes and cdrom. UDMA/33 (aka UltraDMA/33) is
  ATA-4 and provides faster (and more CPU friendly) transfer modes
  than previous PIO (Programmed processor Input/Output) from previous
  ATA/IDE standards by means of fast DMA controllers.

  ATA Packet Interface (ATAPI) is a protocol used by EIDE tape and
  CD-ROM drives, similar in many respects to the SCSI protocol.

  SMART IDE (Self Monitoring, Analysis and Reporting Technology) was
  designed in order to prevent data corruption and disk crash by
  detecting pre hardware failure conditions (heat, access time, and
  the like...). Disks built since June 1995 may follow this standard.
  The kernel itself don't manage this; however there are quite a
  number of user programs such as smart that can query the status of
  SMART parameters disk.

  If you want to compile this driver as a module ( = code which can be
  inserted in and removed from the running kernel whenever you want),
  say M here and read <file:Documentation/modules.txt>. The module
  will be called ide.o.

  For further information, please read <file:Documentation/ide.txt>.

  If unsure, say Y.

CONFIG_DISCONTIGMEM
  Say Y to upport efficient handling of discontiguous physical memory,
  for architectures which are either NUMA (Non-Uniform Memory Access)
  or have huge holes in the physical address space for other reasons.
  See <file:Documentation/vm/numa> for more.

CONFIG_NUMA
  Say Y to compile the kernel to support NUMA (Non-Uniform Memory
  Access).  This option is for configuring high-end multiprocessor
  server machines.  If in doubt, say N.

CONFIG_ISA
  Find out whether you have ISA slots on your motherboard.  ISA is the
  name of a bus system, i.e. the way the CPU talks to the other stuff
  inside your box.  Other bus systems are PCI, EISA, MicroChannel
  (MCA) or VESA.  ISA is an older system, now being displaced by PCI;
  newer boards don't support it.  If you have ISA, say Y, otherwise N.

CONFIG_PCI
  Find out whether you have a PCI motherboard. PCI is the name of a
  bus system, i.e. the way the CPU talks to the other stuff inside
  your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
  VESA. If you have PCI, say Y, otherwise N.

  The PCI-HOWTO, available from
  <http://www.linuxdoc.org/docs.html#howto>, contains valuable
  information about which PCI hardware does work under Linux and which
  doesn't.

CONFIG_MCA
  MicroChannel Architecture is found in some IBM PS/2 machines and
  laptops.  It is a bus system similar to PCI or ISA. See
  <file:Documentation/mca.txt> (and especially the web page given
  there) before attempting to build an MCA bus kernel.

CONFIG_EISA
  The Extended Industry Standard Architecture (EISA) bus was
  developed as an open alternative to the IBM MicroChannel bus.

  The EISA bus provided some of the features of the IBM MicroChannel
  bus while maintaining backward compatibility with cards made for
  the older ISA bus.  The EISA bus saw limited use between 1988 and
  1995 when it was made obsolete by the PCI bus.

  Say Y here if you are building a kernel for an EISA-based machine.

  Otherwise, say N.

CONFIG_HOTPLUG
  Say Y here if you want to plug devices into your computer while
  the system is running, and be able to use them quickly.  In many
  cases, the devices can likewise be unplugged at any time too.

  One well known example of this is PCMCIA- or PC-cards, credit-card
  size devices such as network cards, modems or hard drives which are
  plugged into slots found on all modern laptop computers.  Another
  example, used on modern desktops as well as laptops, is USB.

  Enable HOTPLUG and KMOD, and build a modular kernel.  Get agent
  software (at <http://linux-hotplug.sourceforge.net/>) and install it.
  Then your kernel will automatically call out to a user mode "policy
  agent" (/sbin/hotplug) to load modules and set up software needed
  to use devices as you hotplug them.

CONFIG_PCMCIA
  Say Y here if you want to attach PCMCIA- or PC-cards to your Linux
  computer.  These are credit-card size devices such as network cards,
  modems or hard drives often used with laptops computers.  There are
  actually two varieties of these cards: the older 16 bit PCMCIA cards
  and the newer 32 bit CardBus cards.  If you want to use CardBus
  cards, you need to say Y here and also to "CardBus support" below.

  To use your PC-cards, you will need supporting software from David
  Hinds' pcmcia-cs package (see the file <file:Documentation/Changes>
  for location).  Please also read the PCMCIA-HOWTO, available from
  <http://www.linuxdoc.org/docs.html#howto>.

  This driver is also available as a module ( = code which can be
  inserted in and removed from the running kernel whenever you want).
  When compiled this way, there will be modules called pcmcia_core.o
  and ds.o.  If you want to compile it as a module, say M here and
  read <file:Documentation/modules.txt>.

CONFIG_KCORE_ELF
  If you enabled support for /proc file system then the file
  /proc/kcore will contain the kernel core image. This can be used
  in gdb:

  $ cd /usr/src/linux ; gdb vmlinux /proc/kcore

  You have two choices here: ELF and A.OUT. Selecting ELF will make
  /proc/kcore appear in ELF core format as defined by the Executable
  and Linking Format specification. Selecting A.OUT will choose the
  old "a.out" format which may be necessary for some old versions
  of binutils or on some architectures.

  This is especially useful if you have compiled the kernel with the
  "-g" option to preserve debugging information. It is mainly used
  for examining kernel data structures on the live kernel so if you
  don't understand what this means or are not a kernel hacker, just
  leave it at its default value ELF.

CONFIG_BINFMT_ELF
  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.linuxdoc.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).

  If you want to compile this as a module ( = code which can be
  inserted in and removed from the running kernel whenever you want),
  say M here and read <file:Documentation/modules.txt>.  The module
  will be called binfmt_elf.o. Saying M or N here is dangerous because
  some crucial programs on your system might be in ELF format.

CONFIG_BINFMT_MISC
  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 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.linuxdoc.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, and <file:Documentation/java.txt> for information about how
  to include Java support.

  You must say Y to "/proc file system support" (CONFIG_PROC_FS) to
  use this part of the kernel.

  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.o. If you
  don't know what to answer at this point, say Y.

CONFIG_VGA_CONSOLE
  Saying Y here will allow you to use Linux in text mode through a
  display that complies with the generic VGA standard. Virtually
  everyone wants that.

  The program SVGATextMode can be used to utilize SVGA video cards to
  their full potential in text mode. Download it from
  <ftp://ibiblio.org/pub/Linux/utils/console/>.

  Say Y.

CONFIG_SCSI
  If you want to use a SCSI hard disk, SCSI tape drive, SCSI CD-ROM or
  any other SCSI device under Linux, say Y and make sure that you know
  the name of your SCSI host adapter (the card inside your computer
  that "speaks" the SCSI protocol, also called SCSI controller),
  because you will be asked for it.

  You also need to say Y here if you want support for the parallel
  port version of the 100 MB IOMEGA ZIP drive.

  This driver is also available as a module ( = code which can be
  inserted in and removed from the running kernel whenever you want).
  The module will be called scsi_mod.o.  If you want to compile it as
  a module, say M here and read <file:Documentation/modules.txt> and
  <file:Documentation/scsi.txt>.  However, do not compile this as a
  module if your root file system (the one containing the directory /)
  is located on a SCSI device.

CONFIG_NETDEVICES
  You can say N here if you don't intend to connect your Linux box to
  any other computer at all or if all your connections will be over a
  telephone line with a modem either via UUCP (UUCP is a protocol to
  forward mail and news between unix hosts over telephone lines; read
  the UUCP-HOWTO, available from
  <http://www.linuxdoc.org/docs.html#howto>) or dialing up a shell
  account or a BBS, even using term (term is a program which gives you
  almost full Internet connectivity if you have a regular dial up
  shell account on some Internet connected Unix computer. Read
  <http://www.bart.nl/~patrickr/term-howto/Term-HOWTO.html>).

  You'll have to say Y if your computer contains a network card that
  you want to use under Linux (make sure you know its name because you
  will be asked for it and read the Ethernet-HOWTO (especially if you
  plan to use more than one network card under Linux)) or if you want
  to use SLIP (Serial Line Internet Protocol is the protocol used to
  send Internet traffic over telephone lines or null modem cables) or
  CSLIP (compressed SLIP) or PPP (Point to Point Protocol, a better
  and newer replacement for SLIP) or PLIP (Parallel Line Internet
  Protocol is mainly used to create a mini network by connecting the
  parallel ports of two local machines) or AX.25/KISS (protocol for
  sending Internet traffic over amateur radio links).

  Make sure to read the NET-3-HOWTO. Eventually, you will have to read
  Olaf Kirch's excellent and free book "Network Administrator's
  Guide", to be found in <http://www.linuxdoc.org/docs.html#guide>. If
  unsure, say Y.

CONFIG_CD_NO_IDESCSI
  If you have a CD-ROM drive that is neither SCSI nor IDE/ATAPI, say Y
  here, otherwise N. Read the CD-ROM-HOWTO, available from
  <http://www.linuxdoc.org/docs.html#howto>.

  Note that the answer to this question doesn't directly affect the
  kernel: saying N will just cause the configurator to skip all
  the questions about these CD-ROM drives. If you are unsure what you
  have, say Y and find out whether you have one of the following
  drives.

  For each of these drivers, a file Documentation/cdrom/{driver_name}
  exists. Especially in cases where you do not know exactly which kind
  of drive you have you should read there. Most of these drivers use a
  file drivers/cdrom/{driver_name}.h where you can define your
  interface parameters and switch some internal goodies.

  All these CD-ROM drivers are also usable as a module ( = code which
  can be inserted in and removed from the running kernel whenever you
  want). If you want to compile them as module, say M instead of Y and
  read <file:Documentation/modules.txt>.

  If you want to use any of these CD-ROM drivers, you also have to
  answer Y or M to "ISO 9660 CD-ROM file system support" below (this
  answer will get "defaulted" for you if you enable any of the Linux
  CD-ROM drivers).

CONFIG_DEVFS_FS
  This is support for devfs, a virtual file system (like /proc) which
  provides the file system interface to device drivers, normally found
  in /dev. Devfs does not depend on major and minor number
  allocations. Device drivers register entries in /dev which then
  appear automatically, which means that the system administrator does
  not have to create character and block special device files in the
  /dev directory using the mknod command (or MAKEDEV script) anymore.

  This is work in progress. If you want to use this, you *must* read
  the material in <file:Documentation/filesystems/devfs/>, especially
  the file README there.

  If unsure, say N.

CONFIG_DEVFS_DEBUG
  If you say Y here, then the /dev file system code will generate
  debugging messages. See the file
  <file:Documentation/filesystems/devfs/boot-options> for more
  details.

  If unsure, say N.

CONFIG_PM
  "Power Management" means that parts of your computer are shut
  off or put into a power conserving "sleep" mode if they are not
  being used.  There are two competing standards for doing this: APM
  and ACPI.  If you want to use either one, say Y here and then also
  to the requisite support below.

  Power Management is most important for battery powered laptop
  computers; if you have a laptop, check out the Linux Laptop home
  page on the WWW at
  <http://www.cs.utexas.edu/users/kharker/linux-laptop/> and the
  Battery Powered Linux mini-HOWTO, available from
  <http://www.linuxdoc.org/docs.html#howto>.

  Note that, even if you say N here, Linux on the x86 architecture
  will issue the hlt instruction if nothing is to be done, thereby
  sending the processor to sleep and saving power.

CONFIG_ACPI
  ACPI/OSPM support for Linux is currently under development. As such,
  this support is preliminary and EXPERIMENTAL.  Configuring ACPI
  support enables kernel interfaces that allow higher level software
  (OSPM) to manipulate ACPI defined hardware and software interfaces,
  including the evaluation of ACPI control methods.  If unsure, choose
  N here.  Note, this option will enlarge your kernel by about 120K.

  This support requires an ACPI compliant platform (hardware/firmware).
  If both ACPI and Advanced Power Management (APM) support are
  configured, whichever is loaded first shall be used.

  This code DOES NOT currently provide a complete OSPM implementation
  -- it has not yet reached APM's level of functionality.  When fully
  implemented, Linux ACPI/OSPM will provide a more robust functional
  replacement for legacy configuration and power management
  interfaces, including the Plug-and-Play BIOS specification (PnP
  BIOS), the Multi-Processor Specification (MPS), and the Advanced
  Power Management specification (APM).

  Linux support for ACPI/OSPM is based on Intel Corporation's ACPI
  Component Architecture (ACPI CA). The latest ACPI CA source code,
  documentation, debug builds, and implementation status information
  can be downloaded from:
  <http://developer.intel.com/technology/iapc/acpi/downloads.htm>.

  The ACPI Sourceforge project may also be of interest:
  <http://sf.net/projects/acpi/>

CONFIG_ACPI_KERNEL_CONFIG
  If you say `Y' here, Linux's ACPI support will use the
  hardware-level system descriptions found on IA64 machines.

CONFIG_MAGIC_SYSRQ
  If you say Y here, you will have some control over the system even
  if the system crashes for example during kernel debugging (e.g., you
  will be able to flush the buffer cache to disk, reboot the system
  immediately or dump some status information). This is accomplished
  by pressing various keys while holding SysRq (Alt+PrintScreen). It
  also works on a serial console (on PC hardware at least), if you
  send a BREAK and then within 5 seconds a command keypress. The
  keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
  unless you really know what this hack does.

CONFIG_ITANIUM
  Select your IA64 processor type.  The default is Intel Itanium.

CONFIG_MCKINLEY
  Select this to configure for a McKinley processor.

CONFIG_IA64_GENERIC
  This selects the system type of your hardware.  A "generic" kernel
  will run on any supported IA-64 system.  However, if you configure
  a kernel for your specific system, it will be faster and smaller.

  To find out what type of IA-64 system you have, you may want to
  check the IA-64 Linux web site at <http://www.linux-ia64.org/>.
  As of the time of this writing, most hardware is DIG compliant,
  so the "DIG-compliant" option is usually the right choice.

  HP-simulator   For the HP simulator
                 (<http://software.hp.com/ia64linux/>).
  SN1-simulator  For the SGI SN1 simulator.
  DIG-compliant  For DIG ("Developer's Interface Guide") compliant
                 system.

  If you don't know what to do, choose "generic".

CONFIG_IA64_PAGE_SIZE_4KB
  This lets you select the page size of the kernel.  For best IA-64
  performance, a page size of 8KB or 16KB is recommended.  For best
  IA-32 compatibility, a page size of 4KB should be selected (the vast
  majority of IA-32 binaries work perfectly fine with a larger page
  size).  For Itanium systems, do NOT chose a page size larger than
  16KB.

  4KB                For best IA-32 compatibility
  8KB                For best IA-64 performance
  16KB               For best IA-64 performance
  64KB               Not for Itanium.

  If you don't know what to do, choose 8KB.

CONFIG_ITANIUM_BSTEP_SPECIFIC
  Select this option to build a kernel for an Itanium prototype system
  with a B-step CPU.  You have a B-step CPU if the "revision" field in
  /proc/cpuinfo has a value in the range from 1 to 4.

CONFIG_IA64_MCA
  Say Y here to enable machine check support for IA-64.  If you're
  unsure, answer Y.

CONFIG_DISABLE_VHPT
  The Virtual Hash Page Table (VHPT) enhances virtual address
  translation performance.  Normally you want the VHPT active but you
  can select this option to disable the VHPT for debugging.  If you're
  unsure, answer N.

CONFIG_MCKINLEY_ASTEP_SPECIFIC
  Select this option to build a kernel for an IA64 McKinley system
  with any A-stepping CPU.

CONFIG_MCKINLEY_A0_SPECIFIC
  Select this option to build a kernel for an IA64 McKinley system
  with an A0 or A1 stepping CPU.

CONFIG_IA64_DEBUG_CMPXCHG
  Selecting this option turns on bug checking for the IA64
  compare-and-exchange instructions.  This is slow!  Itaniums
  from step B3 or later don't have this problem. If you're unsure,
  select N.

CONFIG_IA64_DEBUG_IRQ
  Selecting this option turns on bug checking for the IA64 irq_save
  and restore instructions.  It's useful for tracking down spinlock
  problems, but slow!  If you're unsure, select N.

CONFIG_IA64_EARLY_PRINTK
  Selecting this option uses the VGA screen for printk() output before
  the consoles are initialised.  It is useful for debugging problems
  early in the boot process, but only if you have a VGA screen
  attached.  If you're unsure, select N.

CONFIG_IA64_PRINT_HAZARDS
  Selecting this option prints more information for Illegal Dependency
  Faults, that is, for Read after Write, Write after Write or Write
  after Read violations.  This option is ignored if you are compiling
  for an Itanium A step processor (CONFIG_ITANIUM_ASTEP_SPECIFIC).  If
  you're unsure, select Y.

CONFIG_PERFMON
  Selects whether support for the IA-64 performance monitor hardware
  is included in the kernel.  This makes some kernel data-structures a
  little bigger and slows down execution a bit, but it is still
  usually a good idea to turn this on.  If you're unsure, say N.

CONFIG_IA64_PALINFO
  If you say Y here, you are able to get PAL (Processor Abstraction
  Layer) information in /proc/pal.  This contains useful information
  about the processors in your systems, such as cache and TLB sizes
  and the PAL firmware version in use.

  To use this option, you have to check that the "/proc file system
  support" (CONFIG_PROC_FS) is enabled, too.

CONFIG_IA32_SUPPORT
  IA64 processors can run IA32 (that is, x86) binaries by emulating
  the IA32 instruction set.  Say Y here to build in kernel support for
  this.  If in doubt, say Y.

CONFIG_EFI_VARS
  If you say Y here, you are able to get EFI (Extensible Firmware
  Interface) variable information in /proc/efi/vars.  You may read,
  write, create, and destroy EFI variables through this interface.

  To use this option, you have to check that the "/proc file system
  support" (CONFIG_PROC_FS) is enabled, too.

CONFIG_DEBUG_KERNEL
  Say Y here if you are developing drivers or trying to debug and
  identify kernel problems.

CONFIG_DEBUG_SLAB
  Say Y here to have the kernel do limited verification on memory
  allocation as well as poisoning memory on free to catch use of freed
  memory.

CONFIG_DEBUG_SPINLOCK
  Say Y here and build SMP to catch missing spinlock initialization
  and certain other kinds of spinlock errors commonly made.  This is
  best used in conjunction with the NMI watchdog so that spinlock
  deadlocks are also debuggable.