Uh, XP Home can't join and Active Directory domain. That's why businesses bought it, dipshit. NONE of the "home" versions of Windows can join a domain.

Also FYI the octane requirement can be related to timing advance, where a lower-compression turbocharged engine with more advanced timing would need higher octane gas to make longer burns from each spark (higher octane gas burns longer than lower octane gas). The earlier spark sets off a longer-burn time of gas timed to the timing, needing the longer-burn ability of the 92+ octane. An old simple truck with 0 BDC timing would be happy with 87 octane, where a newer engine with 15 BDC timing advance would be better with 92+ octane.

Fuck this is way off topic from hard drives, sorry. Just needed to fill in some missing info.

As for hard drives, the more, the better. RAID is for safety now, and SSD's are for speed where we used to have RAID-0. ETC

Let's presume that consumer drives don't fail for 3 years, and enterprise drives don't fail for whatever their warranty period is (or at least neither suffers significant failure figures during those time periods). Let me then compare the price of a comparable consumer and enterprise drive on NewEgg:

Consumer drive: WD3001FAEX (3TB, 7200RPM, 64MB cache, 6gbit/s): $220, 2y warranty
Enterprise drive: WD3000FYYZ (3TB, 7200RPM, 64MB cache, 6gbit/s): $340, 5y warranty

Now, we know the data shows consumer drives are highly reliable for 3 years, after which they get reliable, so let's presume you replace at your own cost every 3 years. Enterprise drives are probably no more reliable, but replacements are free between years 3 and 5, so let's say you replace at your own cost every 5 years. You get:

Consumer drive, average cost per year: ~$73
Enterprise drive, average cost per year: ~$68

Not a huge difference there, and if both drives are really equally reliable, it doesn't really make much of a difference which you pick.

All the newer shelves came preloaded with Coraid-approved drives. As I said, there's hundreds of drives involved here, a lot of SATA 1TB and 2TB and some SAS 600GB. I think out of the later drives, we've had two fail. Maybe three.

Asked about it, Coraid said, yes, the warranty is better on "Enterprise-class" or "RAID-class" drives, but also, the firmware is different. They claim that drives intended for the consumer / SOHO market spend a lot of time retrying marginal reads before declaring an unreadable sector and sparing it. They say that SAN-class drives limit the retry time, because the array controller handles it more efficiently, since it has the big-picture view.

The also say that the drives are optimized for close-quarters operation, all jammed together in an array, handling vibration and heat build-up slightly differently, and that they have minor differences to keep lubrication from migrating out of the spindle bearing under continuous operation. I don't know but I imagine loss of spindle bearing lube would add vibration and make any but the best reads more marginal.

I don't know for sure, but we've spent a great deal of US dollars on their products and our experience has borne out the fact that there's a definite difference in arrays.

As for corporate desktop and/or server use, well, I don't really know. Our servers that have one to four drives were mostly shipped with those drives, so we didn't choose them. I can't tell you if they are enterprise class drives, but I imagine they are, based on the replacement costs. And I know about what some of those costs are, or anyhow I know they were way more than I personally pay for drives for home desktop and server use. I know that because occasionally they fail, and I have to buy new ones.

But consumer hard drives are so much cheaper that it's not really cost effective anymore to buy Enterprise drives.

Do you actually do Enterprise Storage? Because I know people who do.

At the really high end, the machines automatically call home and report a fault to the vendor. The vendor then dispatches someone to replace the faulty bit within the SLA.

In my experience, and from what I've been told by people who do this for a living, the Enterprise class drives come with the benefit of a warranty in which the manufacturer is contractually obligated to get you a replacement within a fixed amount of time.

Anyone doing real enterprise class storage for real mission critical things -- using commercial SATA drives is just not done unless it's cheap/bulk storage. Sure, you pay through the nose to the vendor for that kind of support, but you also have guaranteed service time and availability.

I just don't see evidence of people who do this at an enterprise scale cheaping out on disks for the important stuff.

No difference between enterprise and home HDD's that I know of.

As for what "hammering and heavy use " of a drive is?

The biggest killer of HDD's is something called the CSS test cycle.

CSS = Contact Start Stop where the drive is booted up, spun up, and then shut down repetitively.

Generally, a HDD sitting there spinning away is not what kill them off,
however turning them on-off-on-off a lot is the most abusive thing that you can do.

I still think WD makes the best quality out there, but that's just my opinion.

just my 0.02 worth...

Australia displays the "Research Octane Number" on the pumps, while the US diplays the "Anti-Knock Index", which is:
((Research Octane Number) + (Motor Octane Number)) / 2

Since MON is often 8-10 points lower for the same fuel, this results in 4-5 points lower on the pump display in the US.

I got the warranty info directly from WD's site and spec sheets. RPM is NOT the primary factor in determining seek time, that only affects rotational latency, which is one of at least 4 components of access time, the other three being track seek time, head settling time, and head select time. Seek time is generally the largest of those, rotational latency second largest, and the others are minor by comparison.

Amount of ECC is not only dependent upon 512/4k (AF) drive, that's one factor, but most "enterprise" drives from most manufacturers have greater ECC and most use lower track densities to allow faster positioning (faster seek). For instance, compare the data sheets for the 7200RPM desktop [seagate.com] and Enterprise (Constellation ES) [seagate.com] drives from Seagate. Note the "enhanced error correction" and better "non-recoverable read error" rates (which are directly related to ECC recoverablity) on the ES (enterprise) drive, and that's comparing a 512b sector ES drive to a 4K/AF desktop drive.

As I said, you analysis was generally good, you just missed a the 3 items I noted.