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CDROM_NOMINAL_PERFORMANCE_DESCRIPTOR structure

The CDROM_NOMINAL_PERFORMANCE_DESCRIPTOR structure gives the host an approximation of logical unit performance. It is returned by the IOCTL_CDROM_GET_PERFORMANCE I/O control request when the request type is CdromPerformanceRequest and the Except field of the CDROM_PERFORMANCE_HEADER is false (0). Separate descriptors are returned for read and write performance requests. The fields in CDROM_NOMINAL_PERFORMANCE_DESCRIPTOR correspond to the similarly named fields in the "Performance Descriptor - Nominal Performance" table described in the MultiMedia Command Set - 6 (MMC-6) specification.

Syntax


typedef struct _CDROM_NOMINAL_PERFORMANCE_DESCRIPTOR {
  UCHAR  StartLba[4];
  UCHAR StartPerformance[4];
  UCHAR  EndLba[4];
  UCHAR  EndPerformance[4];
} CDROM_NOMINAL_PERFORMANCE_DESCRIPTOR, *PCDROM_NOMINAL_PERFORMANCE_DESCRIPTOR;

Members

StartLba

The StartLba field (Start LBA) contains the first logical block address of the extent described by this descriptor.

StartPerformance

The StartPerformance field (Start Performance) contains the nominal logical unit performance at the Start LBA in kilobytes per second.

EndLba

The EndLba field (End LBA) contains the last logical block address of the extent described by this descriptor.

EndPerformance

The EndPerformance field (End Performance) contains the nominal logical unit performance at the End LBA in kilobytes per second.

Requirements

Header

Ntddcdrm.h (include Ntddcdrm.h)

See also

IOCTL_CDROM_GET_PERFORMANCE
CDROM_PERFORMANCE_HEADER

 

 

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