MAKEDEV

Section: Linux Programmer's Manual (8)
Updated: 14th August 1994
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NAME

MAKEDEV - create devices

SYNOPSIS

cd dev; ./MAKEDEV -V
cd dev; ./MAKEDEV [ -n ] [ -v ] update
cd dev; ./MAKEDEV [ -n ] [ -v ] [ -d ] device ...

DESCRIPTION

MAKEDEV is a script that will create the devices in /dev used to interface with drivers in the kernel.

Note that programs giving the error ``ENOENT: No such file or directory'' normally means that the device file is missing, whereas ``ENODEV: No such device'' normally means the kernel does not have the driver configured or loaded.

OPTIONS

-V: Print out version (actually RCS version information) and exit.
-n: Do not actually update the devices, just print the actions that would be performed.
-d: Delete the devices. The main use for this flag is by MAKEDEV itself.
-v: Be verbose. Print out the actions as they are performed. This is the same output as produced by -n.

CUSTOMISATION

Since there is currently no standardisation in what names are used for system users and groups, it is possible that you may need to modify MAKEDEV to reflect your site's settings. Near the top of the file is a mapping from device type to user, group and permissions (e.g. all CD-ROM devices are set from the $cdrom variable). If you wish to change the defaults, this is the section to edit.

DEVICES

General Options
update: This only works on kernels which have /proc/interrupts (introduced during 1.1.x). This file is scanned to see what devices are currently configured into the kernel, and this is compared with the previous settings stored in the file called DEVICES. Devices which are new since then or have a different major number are created, and those which are no longer configured are deleted.
generic: Create a generic subset of devices. This is the standard devices, plus floppy drives, various hard drives, pseudo-terminals, console devices, basic serial devices, busmice, and printer ports.
std: Standard devices. These are: mem - acess to physical memory; kmem - access to kernel virtual memory; null - null device (infinite sink); port - access to I/O ports; zero - null byte source (infinite source); core - symlink to /proc/kcore (for kernel debugging); full - always returns ENOSPACE on write; ram - ramdisk; tty - to access the controlling tty of a process.
local: This simply runs MAKEDEV.local. This is a script that can create any local devices.
Virtual Terminals
console: This creates the devices associated with the console. This is the virtual terminals ttyx, where x can be from 0 though 63. The device tty0 is the currently active vt, and is also known as console. For each vt, there are two devices vcsx and vcsax, which are used to generate screen-dumps of the vt (the vcsx is just the text, and vcsax includes the attributes).
Serial Devices
ttyS{0..63}: Serial ports and corresponding dialout device. For device ttySx, there is also the device cuax which is used to dial out with. This can avoid the need for cooperative locks in simple situations.
cyclades: Dial-in and dial-out devices for the cyclades intelligent I/O serial card. The dial in device is ttyCx and the corresponding dial-out device is cubx By default devices for 7 lines are created, but this can be changed to 15 by removing the comment.
Pseudo Terminals
pty[p-s]: Each possible argument will create a bank of 16 master and slave pairs. The current kernel (1.2) is limited to 64 such pairs. The master pseudo-terminals are pty[p-s][0-9a-f], and the slaves are tty[p-s][0-9a-f].
Parallel Ports
lp: Standard parallel ports. The devices are created lp0, lp1, and lp2. These correspond to ports at 0x3bc, 0x378 and 0x278. Hence, on some machines, the first printer port may actually be lp1.
par: Alternative to lp. Ports are named parx instead of lpx.
Bus Mice
busmice: The various bus mice devices. This creates the following devices: logimouse (Logitech bus mouse), psmouse (PS/2-style mouse), msmouse (Microsoft Inport bus mouse) and atimouse (ATI XL bus mouse) and jmouse (J-mouse).
Joystick Devices
js: Joystick. Creates js0 and js1.
Disk Devices
fd[0-7]: Floppy disk devices. The device fdx is the device which autodetects the format, and the additional devices are fixed format (whose size is indicated in the name). The other devices are named as fdxLn. The single letter L identifies the type of floppy disk (d = 5.25" DD, h = 5.25" HD, D = 3.5" DD, H = 3.5" HD, E = 3.5" ED). The number n represents the capacity of that format in K. Thus the standard formats are fdxd360, fdxh1200, fdxD720, fdxH1440, and fdxE2880.
: For more information see Alain Knaff's fdutils package.
: Devices fd0* through fd3* are floppy disks on the first controller, and devices fd4* through fd7* are floppy disks on the second controller.
hd[a-d]: AT hard disks. The device hdx provides access to the whole disk, with the partitions being hdx[0-20]. The four primary partitions are hdx1 through hdx4, with the logical partitions being numbered from hdx5 though hdx20. (A primary partition can be made into an extended partition, which can hold 4 logical partitions). By default, only the devices for 4 logical partitions are made. The others can be made by uncommenting them.
: Drives hda and hdb are the two on the first controller. If using the new IDE driver (rather than the old HD driver), then hdc and hdd are the two drives on the secondary controller. These devices can also be used to acess IDE CDROMs if using the new IDE driver.
xd[a-d]: XT hard disks. Partitions are the same as IDE disks.
sd[a-z], sd[a-c][a-z], sdd[a-x]: SCSI hard disks. The partitions are similar to the IDE disks, but there is a limit of 11 logical partitions (sdx5 through sdx15). This is to allow there to be 128 SCSI disks.
loop: Loopback disk devices. These allow you to use a regular file as a block device. This means that images of filesystems can be mounted, and used as normal. This creates 8 devices loop0 through loop7.
Tape Devices
st[0-7]: SCSI tapes. This creates the rewinding tape device stx and the non-rewinding tape device nstx.
qic: QIC-80 tapes. The devices created are rmt8, rmt16, tape-d, and tape-reset.
ftape: Floppy driver tapes (QIC-117). There are 4 methods of access depending on the floppy tape drive. For each of access methods 0, 1, 2 and 3, the devices rftx (rewinding) and nrftx (non-rewinding) are created. For compatability, devices ftape and nftape are symlinks to rft0 and nrft0 respectively.
CDROM Devices
scd[0-7]: SCSI CD players.
sonycd: Sony CDU-31A CD player.
mcd: Mitsumi CD player.
cdu535: Sony CDU-535 CD player.
lmscd: LMS/Philips CD player.
sbpcd{,1,2,3}: Sound Blaster CD player. The kernel is capable of supporting 16 CDROMs, each of which is accessed as sbpcd[0-9a-f]. These are assigned in groups of 4 to each controller. sbpcd is a symlink to sbpcd0.
Scanner
logiscan: Logitech ScanMan32 & ScanMan 256.
m105scan: Mustek M105 Handscanner.
ac4096: A4Tek Color Handscanner.
Audio
audio: This creates the audio devices used by the sound driver. These include mixer, sequencer, dsp, and audio.
pcaudio: Devices for the PC Speaker sound driver. These are pcmixer. pxsp, and pcaudio.
Miscellaneous
sg: Generic SCSI devices. The devices created are sga through sgh and sg0 through sg7. These allow arbitary commands to be sent to any SCSI device. This allows for querying information about the device, or controlling SCSI devices that are not one of disk, tape or CDROM (e.g. scanner, writeable CDROM).
fd: To allow an arbitary program to be fed input from file descriptor x, use /dev/fd/x as the file name. This also creates BR /dev/stdin , BR /dev/stdout , and BR /dev/stderr . (Note, these are just symlinks into /proc/self/fd).
ibcs2: Devices (and symlinks) needed by the IBCS2 emulation.
apm: Devices for power management.
dcf: Driver for DCF-77 radio clock.
helloworld: Kernel modules demonstration device. See the modules source.
Network Devices: Linux used to have devices in /dev for controlling network devices, but that is no longer the case. To see what network devices are known by the kernel, look at /proc/net/dev.

AUTHOR

Nick Holloway

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