configure.help

《嵌入式系统设计与实例开发实验教材二源码》Linux内核移植与编译实验

  system, but the driver will do nothing.

Timer LED
CONFIG_LEDS_TIMER
  If you say Y here, one of the system LEDs (the green one on the
  NetWinder, the amber one on the EBSA285, or the red one on the LART)
  will flash regularly to indicate that the system is still
  operational. This is mainly useful to kernel hackers who are
  debugging unstable kernels.

  The LART uses the same LED for both Timer LED and CPU usage LED
  functions. You may choose to use both, but the Timer LED function
  will overrule the CPU usage LED.

CPU usage LED
CONFIG_LEDS_CPU
  If you say Y here, the red LED will be used to give a good real
  time indication of CPU usage, by lighting whenever the idle task
  is not currently executing.

  The LART uses the same LED for both Timer LED and CPU usage LED
  functions. You may choose to use both, but the Timer LED function
  will overrule the CPU usage LED.

Kernel FP software completion
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.

# Choice: himem
High Memory support
CONFIG_NOHIGHMEM
  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
  However, the address space of 32-bit x86 processors is only 4
  Gigabytes large. That means that, if you have a large amount of
  physical memory, not all of it can be "permanently mapped" by the
  kernel. The physical memory that's not permanently mapped is called
  "high memory".

  If you are compiling a kernel which will never run on a machine with
  more than 960 megabytes of total physical RAM, answer "off" here (default
  choice and suitable for most users). This will result in a "3GB/1GB"
  split: 3GB are mapped so that each process sees a 3GB virtual memory
  space and the remaining part of the 4GB virtual memory space is used
  by the kernel to permanently map as much physical memory as
  possible.

  If the machine has between 1 and 4 Gigabytes physical RAM, then
  answer "4GB" here.

  If more than 4 Gigabytes is used then answer "64GB" here. This
  selection turns Intel PAE (Physical Address Extension) mode on.
  PAE implements 3-level paging on IA32 processors. PAE is fully
  supported by Linux, PAE mode is implemented on all recent Intel
  processors (Pentium Pro and better). NOTE: If you say "64GB" here,
  then the kernel will not boot on CPUs that don't support PAE!

  The actual amount of total physical memory will either be auto
  detected or can be forced by using a kernel command line option such
  as "mem=256M". (Try "man bootparam" or see the documentation of your
  boot loader (grub, lilo or loadlin) about how to pass options to the
  kernel at boot time.)

  If unsure, say "off".

4GB
CONFIG_HIGHMEM4G
  Select this if you have a 32-bit processor and between 1 and 4
  gigabytes of physical RAM.

64GB
CONFIG_HIGHMEM64G
  Select this if you have a 32-bit processor and more than 4
  gigabytes of physical RAM.

Normal floppy disk support
CONFIG_BLK_DEV_FD
  If you want to use the floppy disk drive(s) of your PC under Linux,
  say Y. Information about this driver, especially important for IBM
  Thinkpad users, is contained in <file:Documentation/floppy.txt>.
  That file also contains the location of the Floppy driver FAQ as
  well as location of the fdutils package used to configure additional
  parameters of the driver at run time.

  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 floppy.o. If you want to compile it as a
  module, say M here and read <file:Documentation/modules.txt>.

iSeries Virtual I/O Disk Support
CONFIG_VIODASD
  If you are running on an iSeries system and you want to use
  virtual disks created and managed by OS/400, say Y.

iSeries Virtual I/O Disk IDE Emulation
CONFIG_VIODASD_IDE
  This causes the iSeries virtual disks to look like IDE disks.
  If you have programs or utilities that only support certain
  kinds of disks, this option will cause iSeries virtual disks
  to pretend to be IDE disks, which may satisfy the program.

Support for PowerMac floppy
CONFIG_MAC_FLOPPY
  If you have a SWIM-3 (Super Woz Integrated Machine 3; from Apple)
  floppy controller, say Y here. Most commonly found in PowerMacs.

RAM disk support
CONFIG_BLK_DEV_RAM
  Saying Y here will allow you to use a portion of your RAM memory as
  a block device, so that you can make file systems on it, read and
  write to it and do all the other things that you can do with normal
  block devices (such as hard drives). It is usually used to load and
  store a copy of a minimal root file system off of a floppy into RAM
  during the initial install of Linux.

  Note that the kernel command line option "ramdisk=XX" is now
  obsolete. For details, read <file:Documentation/ramdisk.txt>.

  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 and read <file:Documentation/modules.txt>. The module will be
  called rd.o.

  Most normal users won't need the RAM disk functionality, and can
  thus say N here.

Default RAM disk size
CONFIG_BLK_DEV_RAM_SIZE
  The default value is 4096. Only change this if you know what are
  you doing. If you are using IBM S/390, then set this to 8192.

Initial RAM disk (initrd) support
CONFIG_BLK_DEV_INITRD
  The initial RAM disk is a RAM disk that is loaded by the boot loader
  (loadlin or lilo) and that is mounted as root before the normal boot
  procedure. It is typically used to load modules needed to mount the
  "real" root file system, etc. See <file:Documentation/initrd.txt>
  for details.

Loopback device support
CONFIG_BLK_DEV_LOOP
  Saying Y here will allow you to use a regular file as a block
  device; you can then create a file system on that block device and
  mount it just as you would mount other block devices such as hard
  drive partitions, CD-ROM drives or floppy drives. The loop devices
  are block special device files with major number 7 and typically
  called /dev/loop0, /dev/loop1 etc.

  This is useful if you want to check an ISO 9660 file system before
  burning the CD, or if you want to use floppy images without first
  writing them to floppy. Furthermore, some Linux distributions avoid
  the need for a dedicated Linux partition by keeping their complete
  root file system inside a DOS FAT file using this loop device
  driver.

  The loop device driver can also be used to "hide" a file system in a
  disk partition, floppy, or regular file, either using encryption
  (scrambling the data) or steganography (hiding the data in the low
  bits of, say, a sound file). This is also safe if the file resides
  on a remote file server. If you want to do this, you will first have
  to acquire and install a kernel patch from
  <ftp://ftp.kerneli.org/pub/kerneli/>, and then you need to
  say Y to this option.

  Note that alternative ways to use encrypted file systems are
  provided by the cfs package, which can be gotten from
  <ftp://ftp.kerneli.org/pub/kerneli/net-source/>, and the newer tcfs
  package, available at <http://tcfs.dia.unisa.it/>. You do not need
  to say Y here if you want to use one of these. However, using cfs
  requires saying Y to "NFS file system support" below while using
  tcfs requires applying a kernel patch. An alternative steganography
  solution is provided by StegFS, also available from
  <ftp://ftp.kerneli.org/pub/kerneli/net-source/>.

  To use the loop device, you need the losetup utility and a recent
  version of the mount program, both contained in the util-linux
  package. The location and current version number of util-linux is
  contained in the file <file:Documentation/Changes>.

  Note that this loop device has nothing to do with the loopback
  device used for network connections from the machine to itself.

  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 loop.o.

  Most users will answer N here.

Network block device support
CONFIG_BLK_DEV_NBD
  Saying Y here will allow your computer to be a client for network
  block devices, i.e. it will be able to use block devices exported by
  servers (mount file systems on them etc.). Communication between
  client and server works over TCP/IP networking, but to the client
  program this is hidden: it looks like a regular local file access to
  a block device special file such as /dev/nd0.

  Network block devices also allows you to run a block-device in
  userland (making server and client physically the same computer,
  communicating using the loopback network device).

  Read <file:Documentation/nbd.txt> for more information, especially
  about where to find the server code, which runs in user space and
  does not need special kernel support.

  Note that this has nothing to do with the network file systems NFS
  or Coda; you can say N here even if you intend to use NFS or Coda.

  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 nbd.o.

  If unsure, say N.

ATA/IDE/MFM/RLL support
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.

Enhanced IDE/MFM/RLL disk/cdrom/tape/floppy support
CONFIG_BLK_DEV_IDE
  If you say Y here, you will use the full-featured IDE driver to
  control up to ten ATA/IDE interfaces, each being able to serve a
  "master" and a "slave" device, for a total of up to twenty ATA/IDE
  disk/cdrom/tape/floppy drives.

  Useful information about large (>540 MB) IDE disks, multiple
  interfaces, what to do if ATA/IDE devices are not automatically
  detected, sound card ATA/IDE ports, module support, and other
  topics, is contained in <file:Documentation/ide.txt>. For detailed
  information about hard drives, consult the Disk-HOWTO and the
  Multi-Disk-HOWTO, available from
  <http://www.linuxdoc.org/docs.html#howto>.

  To fine-tune ATA/IDE drive/interface parameters for improved
  performance, look for the hdparm package at
  <ftp://ibiblio.org/pub/Linux/system/hardware/>.

  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> and
  <file:Documentation/ide.txt>. The module will be called ide-mod.o.
  Do not compile this driver as a module if your root file system (the
  one containing the directory /) is located on an IDE device.

  If you have one or more IDE drives, say Y or M here. If your system
  has no IDE drives, or if memory requirements are really tight, you
  could say N here, and select the "Old hard disk driver" below
  instead to save about 13 KB of memory in the kernel.

Old hard disk (MFM/RLL/IDE) driver
CONFIG_BLK_DEV_HD_ONLY
  There are two drivers for MFM/RLL/IDE hard disks. Most people use
  the newer enhanced driver, but this old one is still around for two
  reasons. Some older systems have strange timing problems and seem to
  work only with the old driver (which itself does not work with some
  newer systems). The other reason is that the old driver is smaller,
  since it lacks the enhanced functionality of the new one. This makes
  it a good choice for systems with very tight memory restrictions, or