A. The DISK_ASYNCH_IO parameter is set to TRUE.
B. The FILESYSTEMIO_OPTIONS parameter is set to NONE.
C. Another session runs the I/O calibration process concurrently.
D. The pending area has not been created before running the I/O calibration process.
Answer: B
参考：http://docs.oracle.com/cd/E11882_01/server.112/e41573/os.htm#PFGRF94412
查看图表检查在I/ O校准过程中得到的错误。在裸设备上没有数据文件。此错误的原因是什么？
You can use the FILESYSTEMIO_OPTIONS initialization parameter to enable or disable asynchronous I/O or direct I/O on file system files. This parameter is platform-specific and has a default value that is best for a particular platform.
FILESYTEMIO_OPTIONS can be set to one of the following values:
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ASYNCH: enable asynchronous I/O on file system files, which has no timing requirement for transmission.
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DIRECTIO: enable direct I/O on file system files, which bypasses the buffer cache.
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SETALL: enable both asynchronous and direct I/O on file system files.
-
NONE: disable both asynchronous and direct I/O on file system files.
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