I want to read a DVD-ROM through the cdb read command from the mmc specification opcode 28h. I issue the command through DeviceIoControl and SCSI_PASS_THROUGH_DIRECT. I am unsure what’s the optimum transfer length in the cdb command for fastest reading. When I look at isobuster with bushound they read 32 sectors at a time before issuing the next command. But I also see DVD-ROM-Readers with a maximum transfer capacity of 131.072 Bytes (2048 Bytes * 64 sectors). What’s best?
My next question is related to the problem. If I read more than one sector at a time for example 32 sectors, what will happen if one of that 32 sectors is unreadable. Will the complete output buffer (32 sectors) be corrupted or will only the unreadable sector be zeroed out, if the buffer was memset with zero before? Or will the buffer be good till the position of the sector and there after be defective or zero? Sorry for my noob questions. But I can’t find answers on the net and in the mmc docs.