Updated: April 19, 2023

Driver for ATA/IDE disk interface and ATAPI CD-ROM interface (QNX Neutrino)

Note: You must be root or have the right abilities to start this driver.


devb-eide [blk option[,option]...]
          [cam option[,option]...]
          [cdrom option[,option]...]
          [disk option[,option]...]
          [eide option[,option]...]
          [fs_type options] &

Runs on:

QNX Neutrino


Note: Use commas (,) to separate the options. You can put the blk, cam, cdrom, disk, and eide groups of options in any order.
blk options
The blk options control If specified, they must follow the blk keyword.
cam options
The cam options control If specified, they must follow the cam keyword.
cdrom options
The cdrom options control the driver's interface to If specified, they must follow the cdrom keyword.
disk options
The disk options control the driver's interface to If specified, they must follow the disk keyword.
eide options
The eide options control the driver's interface to the EIDE controller. If you've installed multiple controllers, you can repeat these options for each controller. Remember, however, to specify the eide keyword before each controller's set of options.
  • Interface-specific options:
    Use alternate status register for polling. Off by default.
    Board-specific options.
    The channel number of the controller (0 or 1).
    Set the layout between I/O registers. The default is 0.
    The device ID of the controller.
    Enable the chipset interface.
    The I/O port of the interface. By default, it's detected automatically. Use the vaddr option if this is a virtual address.
    The interrupt used by the controller.
    The amount of time, in milliseconds, to wait for a not-BSY status after interrupt. The default is 20 ms.
    Specify master device options. For device-specific options, see below.
    Don't use BIOS transfer mode settings. The default is to use them.
    Don't use busmastering. Specify this option if you want to disable DMA.
    Don't match the device defect list.
    Don't scan legacy addresses (0x1f0, 0x170).
    Don't scan for master devices.
    Don't reset devices at initialization.
    Don't scan for slave devices.
    The PCI index of the controller in the machine, where index is a value between 0 and the number of adapters.
    Set the priority of the processing thread. The default is 21.
    The number of times to retry initialization resets. The default is 1.
    Specify slave device options. For device-specific options, see below.
    Set the spacing offset between I/O ports (IDE command registers). For example, if the ports are located on 4-byte boundaries, set space to 4. The default is 1.
    Set the I/O request timeout in seconds. The default is 10.
    Set the shared memory region. The default is 0.
    The port specified by the ioport is a virtual address. By default, it's a physical address.
    Set the EIDE verbosity level.
    The vendor ID of the controller.
  • Device-specific options:
    Set the APM level (0x7f0xfe). The default is the maximum (0xfe).
    Set the device type to ATA.
    Set the device type to ATAPI.
    Use Cylinder-Head-Sector mode instead of Logical Block Addressing. LBA is used by default.
    Set the read/write Device Ready (DRDY) mode (drdy=off to disable it, or drdy=on to enable).
    Specify the drive geometry.
    Set multi-word DMA mode. Values for mode can be 0-2 (or off to disable).
    Set the number of blocks per interrupt for multiblk mode.
    Don't use busmastering.
    Report the device as nonremovable.
    Set PIO mode. Values for mode can be 0-4 (or off to disable PIO).
    Enable or disable the device read cache (state is on or off).
    Enable SMART monitoring. If there are problems with the drive, the driver puts a message in the system log (see slog2info and slogger2).
    Note: The message is logged only at startup.

    There currently isn't a mechanism to retrieve SMART data.

    The length of time, in seconds, to wait for the device to become ready.
    Note: You must also specify the device type (e.g., master=ata).
    Set ultra DMA mode. Values for mode can be 0-6 (or off to disable).
    Set the device verbosity level.
    wcache=on | off
    Enable or disable the device write cache.
    Set the I/O access width (8, 16, or 32 bits).
fs_type options
The fs_type options control any filesystem (fs-*.so) module being loaded. Here, fs_type is the filesystem type, such as qnx6 for the Power-Safe filesystem. For the list of supported filesystem options, see the reference for the corresponding shared object. For example, for qnx6, see


The devb-eide driver is for the IDE (Integrated Drive Electronics), EIDE (Enhanced IDE), and ATA (AT Attachment) hard disk interfaces, as well as the ATAPI (ATA Packet Interface) CD-ROM interface. This driver autodetects all interfaces.

Note: If you're installing multiple operating systems on the drive, make sure they all use a compatible mode. For example, if your drive is 528 MB and DOS will also be installed on the drive, the driver should be configured to use LBA.

The devb-eide driver's order of preference for the connection modes is as follows:

  1. UDMA (Ultra Direct Memory Access)
  2. MDMA
  3. SDMA
  4. PIO (Programmed Input/Output)

If the underlying hardware supports a mode, it's automatically enabled, and the driver selects the best available mode. If you want the driver to use a lower mode, you need to explicitly disable the higher, better modes. For example, if you want the driver to use PIO, and the hardware also supports UDMA and MDMA, you need to explicitly disable UDMA and MDMA.

The devb-eide driver uses DMA by default. If you want to disable DMA, specify the nobmstr command-line option.

By default, the driver uses LBA (Logical Block Addressing) modes if the drive supports them. If you want the device programmed to CHS (Cylinder-Head-Sector) mode, specify the chs option.

The devb-eide driver closes its standard input, standard output, and standard error immediately after completing its initializations. Any error messages produced during the initialization phase are written to standard error.

When the driver starts, it detects all EIDE devices attached to the chain. For each device, the driver creates an entry in the /dev directory (e.g., a hard drive appears as hdx, where x is the number of the drive, starting from 0). For example, suppose a system has two hard drives installed. The driver creates the following entries in the /dev directory:

Usually the primary master.
Usually the primary slave, or the next drive on the system (the secondary master).

If the system has one hard drive and a CD-ROM, the entries are:

The primary master.
The CD-ROM drive.
Note: A slave drive must have a master drive.

When the driver starts, it displays on the console the type of detected hardware, along with other debugging information that gets sent to the system logger, slogger2. To view the system log, run slog2info.

Note: When you view the output from slog2info, there will likely be a number of ASC_MEDIA_NOT_PRESENT entries. The driver logs these messages if there isn't a CD in the CD-ROM drive. You can generally ignore them.

Troubleshooting for devb-eide

If the driver doesn't detect the interface or drives attached to it:

Here are some other problems that you might encounter and what you should try:

If the drives are detected, but they're running slowly:


Detect all IDE controllers, and list all connected devices:

devb-eide &

Detect an IDE controller at a specific I/O port address and IRQ number, and list all connected devices:

devb-eide eide ioport=0x1f0,irq=14

Detect a PCMCIA disk that is configured in contiguous I/O mapped addressing at a specific I/O port address and IRQ number:

devb-eide eide ioport=0x320:0x32c,irq=7,noslave
Note: For PCMCIA devices configured in contiguous I/O mapped addressing, you should always specify the control block address of the interface by adding an offset (usually 12) to the base address of the port. This isn't required for legacy addressing (0x1f0 or 0x170), where the driver adds the standard control block offset (0x200) automatically.

Detect an IDE controller with specific vendor and device identifiers, and list all connected devices:

devb-eide eide vid=0x8086,did=0x2411,pci=0,chnl=0

Detect an IDE controller with a specific vendor ID, device ID, and channel number, and disable ultra DMA on the master:

devb-eide eide vid=0x8086,did=0x2411,pci=0,chnl=1,master=udma=off

Pass cache and delwri options to, uid and gid options to, and vollabel option to

devb-eide blk cache=2m,delwri=2s cd uid=234,gid=120 dos \
vollabel=ignore &

The cd and dos options apply to any filesystems of those types that are mounted (either by the automatic mounter or a later explicit mount).

You can also pass generic mount options (as described in as follows:

devb-eide blk noatime dos hidden=show,noexec qnx6 ro &

This sets the ST_NOATIME mount bit for all filesystems, and the ST_NOEXEC bit for any DOS filesystem. The mount message also has these bits, which apply only to that mountpoint.


The devb-eide driver causes to adopt various block special devices under /dev. These devices are normally named hdn (or cdn for CD-ROMs), where n is the physical unit number of the device.

This driver could also require the following shared objects:

Binary Required For CD-ROM access For hard-disk access Always

Exit status:

The devb-eide driver terminates only if an error occurs during startup, or if it has successfully forked itself upon startup because it hadn't been initially started in the background.

The devb-eide driver wasn't started in the background and therefore forked itself. The original process terminated with a zero exit status, the forked process continued.
An error occurred during startup.


Unless overridden with the blk automount= option (see, devices are mounted as:

Device Mountpoint Filesystem type
/dev/hd0t177 /hd qnx6
/dev/cd0 /cd cd
/dev/hd0t6 /dos dos
/dev/hd0t11 /dos dos

While there's no limit to the size of a disk or partition, the limit on I/O (i.e., the lseek(), read() and write() functions) depends on the type of filesystem mounted and on whether you use the 32- or 64-bit versions of these functions. This I/O limit has no effect on the partition size for mounted filesystems. The maximum number of blocks is 232.

Known supported functions include:

chmod(), chown(), close(), closedir(), creat(), devctl(), dup(), dup2(), fcntl(), fpathconf(), fstat(), lseek(), mkdir(), mkfifo(), mknod(), open(), opendir(), pathconf(), read(), readdir(), readlink(), rewinddir(), rmdir(), stat(), symlink(), unlink() (not supported for directories), utime(), write()

Note that certain calls (such as pipe(), as well as read() and write() on FIFOs) may require the pipe manager.