Guess again; - On all counts.
1) I am 67 years old, and I have another 35 year old IQ test from Canada Manpower that also rates me in the 99th percentile.
2) Shutting down improperly is the primary cause of "Head Crashes" and yes they do screwup "Software" because they DAMAGE sectors on the HDD making some parts of the "Software" unreadable.
3) If you knew ANYTHING about the way HDDs work you would understand why Mirrored Arrays increase the chance of Simultaneous Hardware Failure of the HDDs in the array.
4) Get ahold of a program called TestHDD and run it on your HDDs. VERY informative. It doesn't just show unreadable sectors, it also gives a graph of the entire drive, showing sectors which are damaged, but still readable, and shows the extent of damge involved. You will notice that the damage, (and there will be some), shows a pattern.
5) HDDs work something like an old time "Record Player". Record Players read the data on "Records" while HDDs read the data on the HDD platters. Record players had "Tone Arms" fitted with a "Needle" which read the data on the Record. When the Record was not being played the "Tone Arm" sat on a "Stand". HDDs have "Read & Write Heads" which read & write data from & to the "Platters"; and when the HDD is not in use those heads are "Parked" - sort of like sitting on the "Tone Arm Stand".
6) The major difference in the method of operation between old time "Record Players" and HDDs, is that with "Record Players" the "Needle" was in "Contact" with the Record, whereas with HDDs, the "Read & Write Heads" are NOT SUPPOSED TO EVER COME IN CONTACT WITH THE PLATTERS !!! Instead they float just above the platters and read or write to them magnetically.
7) What keeps them "Floating above the platters" is an air cushion generated by the spinning of the platters in the drive. What happens when you shut down power to the drive, without first having "Parked" the "Read & Write Heads" ? The answer is the air cushion that holds them up collapses, and then you get a "Head Crash". Think about that, if you are capable of thinking. The drive is still spinning at reduced speed, not fast enough to generate the required "Air Cushion", but plenty fast enough to cause the heads to scrape the platters, bounce back up, fall back down, scrape some more, bounce again, and go on doing that for a while,- ergo the pattern in the damage which you will find by running "TestHDD". Sort of like skipping a sone on water. This causes "Bad Sectors", and it it happens to the "Boot Track" the drive is toast !!!
8) Why do "Mirrored Arrays" significantly increase the chance of Simultaneous Hardware Failure of the drives in the array ? Because in "Mirrored Arrays" both drives are constantly in the same configuration. If the primary drive is reading or writing to the Boot Track, so is the secondary drive in the array; consequently any "Head Crash" will damage the same parts of both drives. And if the Boot Track is killed on one, it gets killed on the other too.
And that is just one reason "Mirrored Arrays" significantly increase the chance of simkultaneous failure of both drives in the array.
