If a mirror (shadow) set is used in a RAID configuration, which level of RAID does not?

Data mapping for a RAID Level 0 array is shown. Following the working principles of RAID Level 1 array, how you would like to fill the following physical disks from the stripes available in logical disk in the given diagram

With general computer organization with cache in it, Overhead for the following lock is likt that : Test-and-set > Compare-and-set > Test-and-Test-and-Set 1. I'm wondering How about without cache?? 2. And CAS lock can be improved in the same way as TAS to TTAS??

Does external fragmentation have a cause? And what can be done to stop it?

Given the following hard disk set with RAID 4 configuration, can you find the missing data of Block2 back? Please write down your calculation steps

The Answer to the given question is provided at the end of the question. I need you to show the full solution to get the given answer. Show all steps where necessary.   During TLB search, the associative lookup time (ε) is 3ns and hit ratio (α) is 70%. For each time memory access, 80ns is needed. Calculate the effective access time. Answer: 106.1ns

1. Given that in a RAID 2 there are 30 disks in total, what is the space efficiency of the RAID 2?  Given that in a RAID 2 there are 25 disks in total, what are the possible space efficiencies of RAID 50?