Say Y here to get to see options for various different block device drivers. This option alone does not add any kernel code. If you say N, all options in this submenu will be skipped and disabled; only do this if you know what you are doing.
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/blockdev/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. To compile this driver as a module, choose M here: the module will be called floppy.
If you have a SWIM-3 (Super Woz Integrated Machine 3; from Apple) floppy controller, say Y here. Most commonly found in PowerMacs.
You should select this option if you want floppy support and you don't have a II, IIfx, Q900, Q950 or AV series.
This enables support for using Chip RAM and Zorro II RAM as a ramdisk or as a swap partition. Say Y if you want to include this driver in the kernel. To compile this driver as a module, choose M here: the module will be called z2ram.
Very old 8 bit hard disk controllers used in the IBM XT computer will be supported if you say Y here. To compile this driver as a module, choose M here: the module will be called xd. It's pretty unlikely that you have one of these: say N.
A standard SEGA Dreamcast comes with a modified CD ROM drive called a "GD-ROM" by SEGA to signify it is capable of reading special disks with up to 1 GB of data. This drive will also read standard CD ROM disks. Select this option to access any disks in your GD ROM drive. Most users will want to say "Y" here. You can also build this as a module which will be called gdrom.
There are many external CD-ROM and disk devices that connect through your computer's parallel port. Most of them are actually IDE devices using a parallel port IDE adapter. This option enables the PARIDE subsystem which contains drivers for many of these external drives. Read <file:Documentation/blockdev/paride.txt> for more information. If you have said Y to the "Parallel-port support" configuration option, you may share a single port between your printer and other parallel port devices. Answer Y to build PARIDE support into your kernel, or M if you would like to build it as a loadable module. If your parallel port support is in a loadable module, you must build PARIDE as a module. If you built PARIDE support into your kernel, you may still build the individual protocol modules and high-level drivers as loadable modules. If you build this support as a module, it will be called paride. To use the PARIDE support, you must say Y or M here and also to at least one high-level driver (e.g. "Parallel port IDE disks", "Parallel port ATAPI CD-ROMs", "Parallel port ATAPI disks" etc.) and to at least one protocol driver (e.g. "ATEN EH-100 protocol", "MicroSolutions backpack protocol", "DataStor Commuter protocol" etc.).
This is the driver for Compaq Smart Array controllers. Everyone using these boards should say Y here. See the file <file:Documentation/blockdev/cpqarray.txt> for the current list of boards supported by this driver, and for further information on the use of this driver.
This is the driver for Compaq Smart Array 5xxx controllers. Everyone using these boards should say Y here. See <file:Documentation/blockdev/cciss.txt> for the current list of boards supported by this driver, and for further information on the use of this driver.
When enabled (Y), this option allows SCSI tape drives and SCSI medium changers (tape robots) to be accessed via a Compaq 5xxx array controller. (See <file:Documentation/blockdev/cciss.txt> for more details.) "SCSI support" and "SCSI tape support" must also be enabled for this option to work. When this option is disabled (N), the SCSI portion of the driver is not compiled.
This driver adds support for the Mylex DAC960, AcceleRAID, and eXtremeRAID PCI RAID controllers. See the file <file:Documentation/blockdev/README.DAC960> for further information about this driver. To compile this driver as a module, choose M here: the module will be called DAC960.
Saying Y here will include support for the MM5415 family of battery backed (Non-volatile) RAM cards. <http://www.umem.com/> The cards appear as block devices that can be partitioned into as many as 15 partitions. To compile this driver as a module, choose M here: the module will be called umem. The umem driver has not yet been allocated a MAJOR number, so one is chosen dynamically.
The User-Mode Linux port includes a driver called UBD which will let you access arbitrary files on the host computer as block devices. Unless you know that you do not need such virtual block devices say Y here.
Writes to the virtual block device are not immediately written to the host's disk; this may cause problems if, for example, the User-Mode Linux 'Virtual Machine' uses a journalling filesystem and the host computer crashes. Synchronous operation (i.e. always writing data to the host's disk immediately) is configurable on a per-UBD basis by using a special kernel command line option. Alternatively, you can say Y here to turn on synchronous operation by default for all block devices. If you're running a journalling file system (like reiserfs, for example) in your virtual machine, you will want to say Y here. If you care for the safety of the data in your virtual machine, Y is a wise choice too. In all other cases (for example, if you're just playing around with User-Mode Linux) you can choose N.
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. To use the loop device, you need the losetup utility, found in the util-linux package, see <ftp://ftp.kernel.org/pub/linux/utils/util-linux/>. 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. There are several ways of encrypting disks. Some of these require kernel patches. The vanilla kernel offers the cryptoloop option and a Device Mapper target (which is superior, as it supports all file systems). If you want to use the cryptoloop, say Y to both LOOP and CRYPTOLOOP, and make sure you have a recent (version 2.12 or later) version of util-linux. Additionally, be aware that the cryptoloop is not safe for storing journaled filesystems. Note that this loop device has nothing to do with the loopback device used for network connections from the machine to itself. To compile this driver as a module, choose M here: the module will be called loop. Most users will answer N here.
Say Y here if you want to be able to use the ciphers that are provided by the CryptoAPI as loop transformation. This might be used as hard disk encryption. WARNING: This device is not safe for journaled file systems like ext3 or Reiserfs. Please use the Device Mapper crypto module instead, which can be configured to be on-disk compatible with the cryptoloop device.
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/blockdev/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. To compile this driver as a module, choose M here: the module will be called nbd. If unsure, say N.
Saying Y or M here will allow the exporting of a single SCSI OSD (object-based storage) object as a Linux block device. For example, if you create a 2G object on an OSD device, you can then use this module to present that 2G object as a Linux block device. To compile this driver as a module, choose M here: the module will be called osdblk. If unsure, say N.
Saying Y or M here will enable support for the Promise SATA SX8 controllers. Use devices /dev/sx8/$N and /dev/sx8/$Np$M.
This driver supports certain USB attached storage devices such as flash keys. If you enable this driver, it is recommended to avoid conflicts with usb-storage by enabling USB_LIBUSUAL. If unsure, say N.
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/blockdev/ramdisk.txt>. To compile this driver as a module, choose M here: the module will be called rd. Most normal users won't need the RAM disk functionality, and can thus say N here.
The default value is 16 RAM disks. Change this if you know what you are doing. If you boot from a filesystem that needs to be extracted in memory, you will need at least one RAM disk (e.g. root on cramfs).
The default value is 4096 kilobytes. Only change this if you know what you are doing.
Support XIP filesystems (such as ext2 with XIP support on) on top of block ram device. This will slightly enlarge the kernel, and will prevent RAM block device backing store memory from being allocated from highmem (only a problem for highmem systems).
If you have a CDROM/DVD drive that supports packet writing, say Y to include support. It should work with any MMC/Mt Fuji compliant ATAPI or SCSI drive, which is just about any newer DVD/CD writer. Currently only writing to CD-RW, DVD-RW, DVD+RW and DVDRAM discs is possible. DVD-RW disks must be in restricted overwrite mode. See the file <file:Documentation/cdrom/packet-writing.txt> for further information on the use of this driver. To compile this driver as a module, choose M here: the module will be called pktcdvd.
This controls the maximum number of active concurrent packets. More concurrent packets can increase write performance, but also require more memory. Each concurrent packet will require approximately 64Kb of non-swappable kernel memory, memory which will be allocated when a disc is opened for writing.
If enabled, write caching will be set for the CD-R/W device. For now this option is dangerous unless the CD-RW media is known good, as we don't do deferred write error handling yet.
This driver provides Support for ATA over Ethernet block devices like the Coraid EtherDrive (R) Storage Blade.
mGine mFlash(gFlash) block device driver
Define size of reserved area that usually used for boot. Unit is KB. All of the block device operation will be taken this value as start offset Examples: 1024 => 1 MB
Support for virtual disk devices as a client under Sun Logical Domains.
Include support for the Xilinx SystemACE CompactFlash interface
This driver implements the front-end of the Xen virtual block device driver. It communicates with a back-end driver in another domain which drives the actual block device.
The block-device backend driver allows the kernel to export its block devices to other guests via a high-performance shared-memory interface. The corresponding Linux frontend driver is enabled by the CONFIG_XEN_BLKDEV_FRONTEND configuration option. The backend driver attaches itself to a any block device specified in the XenBus configuration. There are no limits to what the block device as long as it has a major and minor. If you are compiling a kernel to run in a Xen block backend driver domain (often this is domain 0) you should say Y here. To compile this driver as a module, chose M here: the module will be called xen-blkback.
This is the virtual block driver for virtio. It can be used with lguest or QEMU based VMMs (like KVM or Xen). Say Y or M.
This is a very old hard disk driver that lacks the enhanced functionality of the newer ones. It is required for systems with ancient MFM/RLL/ESDI drives. If unsure, say N.
Say Y here if you want include the Rados block device, which stripes a block device over objects stored in the Ceph distributed object store. More information at http://ceph.newdream.net/. If unsure, say N.