path: root/arch/alpha/Config.help

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_ALPHA
  The Alpha is a 64-bit general-purpose processor designed and
  marketed by the Digital Equipment Corporation of blessed memory, now
  Compaq.  Alpha Linux dates from 1995-1996 and was the first non-x86
  port. The Alpha Linux project has a home page at
  <http://www.alphalinux.org/>.

CONFIG_MATHEMU
  This option is required for IEEE compliant floating point arithmetic
  on the Alpha. The only time you would ever not say Y is to say M in
  order to debug the code. Say Y unless you know what you are doing.

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_ALPHA_GENERIC
  This is the system type of your hardware.  A "generic" kernel will
  run on any supported Alpha system. However, if you configure a
  kernel for your specific system, it will be faster and smaller.

  To find out what type of Alpha system you have, you may want to
  check out the Linux/Alpha FAQ, accessible on the WWW from
  <http://www.alphalinux.org/>. In summary:

  Alcor/Alpha-XLT     AS 600
  Alpha-XL            XL-233, XL-266
  AlphaBook1          Alpha laptop
  Avanti              AS 200, AS 205, AS 250, AS 255, AS 300, AS 400
  Cabriolet           AlphaPC64, AlphaPCI64
  DP264               DP264
  EB164               EB164 21164 evaluation board
  EB64+               EB64+ 21064 evaluation board
  EB66                EB66 21066 evaluation board
  EB66+               EB66+ 21066 evaluation board
  Jensen              DECpc 150, DEC 2000 model 300,
                      DEC 2000 model 500
  LX164               AlphaPC164-LX
  Miata               Personal Workstation 433a, 433au, 500a,
                      500au, 600a, or 600au
  Mikasa              AS 1000
  Noname              AXPpci33, UDB (Multia)
  Noritake            AS 1000A, AS 600A, AS 800
  PC164               AlphaPC164
  Rawhide             AS 1200, AS 4000, AS 4100
  Ruffian             RPX164-2, AlphaPC164-UX, AlphaPC164-BX
  SX164               AlphaPC164-SX
  Sable               AS 2000, AS 2100
  Shark		      DS 20L
  Takara              Takara
  Titan               Privateer
  Wildfire            AlphaServer GS 40/80/160/320

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

CONFIG_ALPHA_ALCOR
  For systems using the Digital ALCOR chipset: 5 chips (4, 64-bit data
  slices (Data Switch, DSW) - 208-pin PQFP and 1 control (Control, I/O
  Address, CIA) - a 383 pin plastic PGA).  It provides a DRAM
  controller (256-bit memory bus) and a PCI interface.  It also does
  all the work required to support an external Bcache and to maintain
  memory coherence when a PCI device DMAs into (or out of) memory.

CONFIG_ALPHA_XL
  XL-233 and XL-266-based Alpha systems.

CONFIG_ALPHA_BOOK1
  Dec AlphaBook1/Burns Alpha-based laptops.

CONFIG_ALPHA_AVANTI
  Avanti AS 200, AS 205, AS 250, AS 255, AS 300, and AS 400-based
  Alphas. Info at
  <http://www.unix-ag.org/Linux-Alpha/Architectures/Avanti.html>.

CONFIG_ALPHA_CABRIOLET
  Cabriolet AlphaPC64, AlphaPCI64 systems.  Derived from EB64+ but now
  baby-AT with Flash boot ROM, no on-board SCSI or Ethernet. 3 ISA
  slots, 4 PCI slots (one pair are on a shared slot), uses plug-in
  Bcache SIMMs.  Requires power supply with 3.3V output.

CONFIG_ALPHA_DP264
  Various 21264 systems with the tsunami core logic chipset.
  API Networks: 264DP, UP2000(+), CS20;
  Compaq: DS10(E,L), XP900, XP1000, DS20(E), ES40.

CONFIG_ALPHA_EB164
  EB164 21164 evaluation board from DEC.  Uses 21164 and ALCOR.  Has
  ISA and PCI expansion (3 ISA slots, 2 64-bit PCI slots (one is
  shared with an ISA slot) and 2 32-bit PCI slots.  Uses plus-in
  Bcache SIMMs. I/O sub-system provides SuperI/O (2S, 1P, FD), KBD,
  MOUSE (PS2 style), RTC/NVRAM.  Boot ROM is Flash.  PC-AT-sized
  motherboard.  Requires power supply with 3.3V output.

CONFIG_ALPHA_EB64P
  Uses 21064 or 21064A and APECs.  Has ISA and PCI expansion (3 ISA,
  2 PCI, one pair are on a shared slot). Supports 36-bit DRAM SIMs.
  ISA bus generated by Intel SaturnI/O PCI-ISA bridge. On-board SCSI
  (NCR 810 on PCI) Ethernet (Digital 21040), KBD, MOUSE (PS2 style),
  SuperI/O (2S, 1P, FD), RTC/NVRAM. Boot ROM is EPROM.  PC-AT size.
  Runs from standard PC power supply.

CONFIG_ALPHA_EB66
  A Digital DS group board.  Uses 21066 or 21066A.  I/O sub-system is
  identical to EB64+.  Baby PC-AT size.  Runs from standard PC power
  supply.  The EB66 schematic was published as a marketing poster
  advertising the 21066 as "the first microprocessor in the world with
  embedded PCI".

CONFIG_ALPHA_EB66P
  Later variant of the EB66 board.

CONFIG_ALPHA_EIGER
  Apparently an obscure OEM single-board computer based on the
  Typhoon/Tsunami chipset family. Information on it is scanty.

CONFIG_ALPHA_JENSEN
  DEC PC 150 AXP (aka Jensen): This is a very old Digital system - one
  of the first-generation Alpha systems. A number of these systems
  seem to be available on the second- hand market. The Jensen is a
  floor-standing tower system which originally used a 150MHz 21064 It
  used programmable logic to interface a 486 EISA I/O bridge to the
  CPU.

CONFIG_ALPHA_LX164
  A technical overview of this board is available at
  <http://www.unix-ag.org/Linux-Alpha/Architectures/LX164.html>.

CONFIG_ALPHA_MIATA
  The Digital PersonalWorkStation (PWS 433a, 433au, 500a, 500au, 600a,
  or 600au).  There is an Installation HOWTO for this hardware at
  <http://members.brabant.chello.nl/~s.vandereijk/miata.html>.

CONFIG_ALPHA_MIKASA
  AlphaServer 1000-based Alpha systems.

CONFIG_ALPHA_NAUTILUS
  Alpha systems based on the AMD 751 & ALI 1543C chipsets.

CONFIG_ALPHA_NONAME
  The AXPpci33 (aka NoName), is based on the EB66 (includes the Multia
  UDB).  This design was produced by Digital's Technical OEM (TOEM)
  group. It uses the 21066 processor running at 166MHz or 233MHz. It
  is a baby-AT size, and runs from a standard PC power supply. It has
  5 ISA slots and 3 PCI slots (one pair are a shared slot). There are
  2 versions, with either PS/2 or large DIN connectors for the
  keyboard.

CONFIG_ALPHA_NORITAKE
  AlphaServer 1000A, AlphaServer 600A, and AlphaServer 800-based
  systems.

CONFIG_ALPHA_RAWHIDE
  AlphaServer 1200, AlphaServer 4000 and AlphaServer 4100 machines.
  See HOWTO at
  <http://www.alphalinux.org/docs/rawhide/4100_install.shtml>.

CONFIG_ALPHA_RUFFIAN
  Samsung APC164UX.  There is a page on known problems and workarounds
  at <http://www.alphalinux.org/faq/FAQ-11.html>.

CONFIG_ALPHA_SABLE
  Digital AlphaServer 2000 and 2100-based systems.

CONFIG_ALPHA_TAKARA
  Alpha 11164-based OEM single-board computer.

CONFIG_ALPHA_WILDFIRE
  AlphaServer GS 40/80/160/320 SMP based on the EV67 core.

CONFIG_ALPHA_PRIMO
  Say Y if you have an AS 1000 5/xxx or an AS 1000A 5/xxx.

CONFIG_ALPHA_GAMMA
  Say Y if you have an AS 2000 5/xxx or an AS 2100 5/xxx.

CONFIG_ALPHA_SRM
  There are two different types of booting firmware on Alphas: SRM,
  which is command line driven, and ARC, which uses menus and arrow
  keys. Details about the Linux/Alpha booting process are contained in
  the Linux/Alpha FAQ, accessible on the WWW from
  <http://www.alphalinux.org/>.

  The usual way to load Linux on an Alpha machine is to use MILO
  (a bootloader that lets you pass command line parameters to the
  kernel just like lilo does for the x86 architecture) which can be
  loaded either from ARC or can be installed directly as a permanent
  firmware replacement from floppy (which requires changing a certain
  jumper on the motherboard). If you want to do either of these, say N
  here. If MILO doesn't work on your system (true for Jensen
  motherboards), you can bypass it altogether and boot Linux directly
  from an SRM console; say Y here in order to do that. Note that you
  won't be able to boot from an IDE disk using SRM.

  If unsure, say N.

CONFIG_ALPHA_LEGACY_START_ADDRESS
  The 2.4 kernel changed the kernel start address from 0x310000
  to 0x810000 to make room for the Wildfire's larger SRM console.

  If you're using aboot 0.7 or later, the bootloader will examine the
  ELF headers to determine where to transfer control. Unfortunately,
  most older bootloaders -- APB or MILO -- hardcoded the kernel start
  address rather than examining the ELF headers, and the result is a
  hard lockup.

  Say Y if you have a broken bootloader.  Say N if you do not, or if
  you wish to run on Wildfire.

CONFIG_ALPHA_LARGE_VMALLOC
  Process creation and other aspects of virtual memory management can
  be streamlined if we restrict the kernel to one PGD for all vmalloc
  allocations.  This equates to about 8GB.

  Under normal circumstances, this is so far and above what is needed
  as to be laughable.  However, there are certain applications (such
  as benchmark-grade in-kernel web serving) that can make use of as
  much vmalloc space as is available.

  Say N unless you know you need gobs and gobs of vmalloc space.

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_KCORE_AOUT
  Not necessary unless you're using a very out-of-date binutils
  version.  You probably want KCORE_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_AOUT
  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.

  As more and more programs are converted to ELF, the use for a.out
  will gradually diminish. If you disable this option it will reduce
  your kernel by one page. This is not much and by itself does not
  warrant removing support. However its removal is a good idea if you
  wish to ensure that absolutely none of your programs will use this
  older executable format. If you don't know what to answer at this
  point then answer Y. If someone told you "You need a kernel with
  QMAGIC support" then you'll have to say Y here. You may answer M to
  compile a.out support as a module and later load the module when you
  want to use a program or library in a.out format. The module will be
  called binfmt_aout.o. Saying M or N here is dangerous though,
  because some crucial programs on your system might still be in A.OUT
  format.

CONFIG_BINFMT_EM86
  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.o. If unsure, say Y.

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_SOUND
  If you have a sound card in your computer, i.e. if it can say more
  than an occasional beep, say Y.  Be sure to have all the information
  about your sound card and its configuration down (I/O port,
  interrupt and DMA channel), because you will be asked for it.

  You want to read the Sound-HOWTO, available from
  <http://www.linuxdoc.org/docs.html#howto>. General information about
  the modular sound system is contained in the files
  <file:Documentation/sound/Introduction>.  The file
  <file:Documentation/sound/README.OSS> contains some slightly
  outdated but still useful information as well.

  If you have a PnP sound card and you want to configure it at boot
  time using the ISA PnP tools (read
  <http://www.roestock.demon.co.uk/isapnptools/>), then you need to
  compile the sound card support as a module ( = code which can be
  inserted in and removed from the running kernel whenever you want)
  and load that module after the PnP configuration is finished.  To do
  this, say M here and read <file:Documentation/modules.txt> as well
  as <file:Documentation/sound/README.modules>; the module will be
  called soundcore.o.

  I'm told that even without a sound card, you can make your computer
  say more than an occasional beep, by programming the PC speaker.
  Kernel patches and supporting utilities to do that are in the pcsp
  package, available at <ftp://ftp.infradead.org/pub/pcsp/>.

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_ISDN
  ISDN ("Integrated Services Digital Networks", called RNIS in France)
  is a special type of fully digital telephone service; it's mostly
  used to connect to your Internet service provider (with SLIP or
  PPP).  The main advantage is that the speed is higher than ordinary
  modem/telephone connections, and that you can have voice
  conversations while downloading stuff.  It only works if your
  computer is equipped with an ISDN card and both you and your service
  provider purchased an ISDN line from the phone company.  For
  details, read <http://alumni.caltech.edu/~dank/isdn/> on the WWW.

  This driver allows you to use an ISDN-card for networking
  connections and as dialin/out device.  The isdn-tty's have a built
  in AT-compatible modem emulator.  Network devices support autodial,
  channel-bundling, callback and caller-authentication without having
  a daemon running.  A reduced T.70 protocol is supported with tty's
  suitable for German BTX.  On D-Channel, the protocols EDSS1
  (Euro-ISDN) and 1TR6 (German style) are supported.  See
  <file:Documentation/isdn/README> for more information.

  If you want to compile the ISDN code 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 isdn.o. If unsure, say N.

CONFIG_SRM_ENV
  If you enable this option, a subdirectory called srm_environment
  will give you access to the most important SRM environment
  variables. If you've got an Alpha style system supporting
  SRC, then it is a good idea to say Yes or Module to this driver.

  This driver is also available as a module and will be called
  srm_env.o if you build it as a module.

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.