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AIX Version 4.3 Kernel and Subsystems Technical Reference, Volume 2

IDEIOREAD (Read) IDE Adapter Device Driver ioctl Operation


Issues a single block Integrated Device Electronics (IDE) read command to a selected IDE ATA device.


The IDEIOREAD operation allows the caller to issue an IDE device read command to a selected device. System management routines use this command for configuring IDE devices.

The arg parameter of the IDEIOREAD operation is the address of an ide_readblk structure. This structure is defined in the /usr/include/sys/ide.h header file.

This command results in the IDE adapter device driver issuing an ATA READ SECTOR read command. The command is set up to read only a single block. The caller supplies:

The maximum block length for this command is 512 bytes. The command will be rejected if the length is found to be larger than this value.

Note: The IDE adapter device driver performs normal error-recovery procedures during execution of this command.

Return Values

When completed successfully, this operation returns a value of 0. Otherwise, a value of -1 is returned and the errno global variable is set to 1 of the following values:

EFAULT Indicates that a bad copy between kernel and user space occurred.
EINVAL Indicates that an IDEIOSTART command was not issued prior to this command. If the IDEIOSTART command was issued, then this indicates the block length field value is too large.
EIO Indicates that an I/O error has occurred. If an EIO value is returned, the caller should retry the IDEIOREAD operation since the first command may have cleared an error condition with the device. In the case of an adapter error, the system error log records the adapter error status information.
ENOCONNECT Indicates that a bus fault has occurred. Generally, the IDE adapter device driver cannot determine which device caused the bus fault, so this error is not logged.
ENODEV Indicates that no IDE device responded to the requested IDE device ID. This return value implies that no device exists at the specified IDE device ID. This condition is not necessarily an error and is not logged.
ENOMEM Indicates insufficient memory is available to complete the command.
ETIMEDOUT Indicates the device did not respond with status before the internal time-out value expired. The caller should retry this command at least once, since the first command may have cleared an error condition with the device. The system error log records this error.


/dev/ide0, /dev/ide1,..., /dev/iden Provide an interface to allow IDE device drivers to access IDE devices or adapters.

Related Information

idedisk IDE device driver or idecdrom IDE device driver.

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