In ATA8-ACSr3e (Section A.3) it says
“Table 127 defines the format of each of the 512-byte block of data that comprise the Extended SMART Self-test log. The maximum size of the self-test log is 65,535 512-byte blocks of data. Devices may support fewer than
65,536 512-byte blocks of data. All multi-byte fields shown in this structure follow the byte ordering described in 3.2.8.”
Based on my understanding of the log (which could be wrong), the Self-test descriptor index points to the newest self test result (i.e., descriptor entry), which means there can be a maximum of 65,535 descriptors. With 19 descriptors on each 512b data block, why is the stated maximum log so long, instead of 3450 (i.e., 65535/19 rounded up.)
Additionally if the index hits the vendor specific maximum value and rolls over back to descriptor entry 1, how does the application client know it rolled over? (Is it because the descriptor entry 2 on data block 0 is non-zero?). Lastly how does the application client know where the previous descriptor is? (Does it keep reading data blocks until the descriptors become zero?)
Thanks
Kevin
Dell, Inc.
