CDROM_NOMINAL_PERFORMANCE_DESCRIPTOR structure (ntddcdrm.h)
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[4]
The StartLba field (Start LBA) contains the first logical block address of the extent described by this descriptor.
StartPerformance[4]
The StartPerformance field (Start Performance) contains the nominal logical unit performance at the Start LBA in kilobytes per second.
EndLba[4]
The EndLba field (End LBA) contains the last logical block address of the extent described by this descriptor.
EndPerformance[4]
The EndPerformance field (End Performance) contains the nominal logical unit performance at the End LBA in kilobytes per second.
Requirements
| Requirement | Value |
|---|---|
| Header | ntddcdrm.h (include Ntddcdrm.h) |