$25 terabyte due by Christmas

Disk drive prices are the underlying building block of storage prices. Despite SSD popularity, there is not now - nor will there ever be - enough semiconductor fab capacity to replace spinning disk capacity with solid state memory.

Disk drive prices have been on a 30-40 percent annual price decline for decades. In the 00s, annual declines even reached 50+ percent for a few years.

That happy trend was brutally cut short 3 years ago by the October, 2011 floods in northern Thailand. Factories were inundated, production ceased, and disk drive prices spiked overnight.

This was good for drive company profits because their costs didn't rise while prices did. But it was bad for spinning disk market penetration because a costly alternative - solid state drives - suddenly looked a whole lot better.

Fast forward 3 years though and the effects of the Thai flooding are behind us. Disk drive prices have resumed their traditional downard march.

Retail price declines

Disk retail price decreases follow a regular pattern. Special short term deals are offered - often requiring a rebate - to touch a new price point. Since many people don't redeem rebates, the actual price is higher.

Then a couple of months later a rebate-hassle-free special will be offered at the same price point. Finally around 9-12 months later the special-with-rebate price becomes the new retail price online. Brick-and-mortar stores lag further.

The best deals

With the holiday season almost upon us expect to see $25/TB drives available on Black Friday specials and before Christmas. The best deals will be on large capacity - 4-6TB - 3.5" external USB 3.0 drives from online stores. While there's nothing magic about $25/TB, it makes for nice round numbers that are easy to promote.

The Storage Bits take

Back in 1982 disk drive prices were about $40-$50 a megabyte for a washing machine-sized box of a few hundred megabyte capacity. Smaller, faster drives arrived in 1983 that dropped that to $20-$25/MB.

So ≈30 years later disk drives cost one-millionth as much per bit - without adjusting for inflation. That amazing progress we owe to the work of the major drive vendors.

Let's hope they're able to continue down that price curve so that in another 30 years we're looking at the $25 dollar exabyte.

Comments welcome, of course. When did the amazing drop in drive prices first surprise you?