WD's surprising little drive

IIRC, it was just 15 years ago that Maxtor shipped the first 1 GB, 3.5" drive.
Written by Robin Harris, Contributor

IIRC, it was just 15 years ago that Maxtor shipped the first 1 GB, 3.5" drive. The usual things happened: database admins all swore it was "too big," techies said it cost too much, and regular users wondered if they could ever fill it up.

DBA's still kvetch about disk size and techies still complain about cost, but regular users wonder a lot less about filling up a disk drive. Even as drives get huge.

Case in point: a 250 GB 2.5" drive I was surprised to see that Western Digital was first out of the gate with that capacity. While well-regarded for their Raptor line of 3.5" drives, they always seemed far behind Toshiba, Seagate and Hitachi in the 2.5" space. Not any more.

Intelliseek I was particularly interested in learning more about WD's Intelliseek technology. So I contacted their PR person, the helpful Heather Skinner, who got together with me and David Chung, the Scorpio product manager, to talk about the new drive.

Intelliseek is an example of the retrospective obviousness of a good idea. Some bright engineer realized that always using the same acceleration and velocity to move the head around wasted energy and created noise.

A 5400 RPM drive's disks rotates 90 times a second. Each rotation takes a bit over 11 milliseconds. So, on average, the head arrives on the track and then sits around twiddling its thumbs for five and half ms waiting for the block to show up (there's some head settling time as well, but let's ignore that). What a waste!

So instead of sticking with what I think disk drives have always done, moving the head with the same urgency no matter what, Bright Engineer looked at slowing down the head acceleration and velocity to only what was required to arrive on time.

Slightly greener and quieter Does it really save any energy? After all, heads are pretty small. David said it was workload dependent: with lots of random small block accesses it will reduce actuator power consumption by as much as 50%. YMMV. It can also reduce this already quiet drive's noise level by as much as 3db.

Some changes to the actuator improved their shock spec to 300 Gs. And they improved their head parking design, which helped non-operating shock.

SATA in the lead This drive is only available with a SATA interface. David said that the notebook world has almost finished its transition to SATA. That didn't take long.

The Storage Bits take There is debate in the industry about whether 2.5" drives will ever displace 3.5" drives as the dominant form factor, despite the trend of the last 50 years. The first disk drive used 24" platters, and ever since the platters have gotten smaller as bit density has increased.

Some objections to the 2.5" form factor are economic: 3.5" capacity is cheaper. Some are mechanical: there isn't enough metal to make 2.5" drives as tough. Others question the performance, saying nothing will replace 15k drives.

It won't be as fast as some past transitions, but I think it will happen. Smaller form factor PCs, power and cooling, engineering improvements and higher volumes will all help make the smaller drives more popular with more people. And WD seems well-positioned to make the transition, if they can keep driving capacity and power improvements.

Update: I just saw that Hitachi is now saying they are shipping 250's in volume as well. But it looks like WD got there first. Update II: I did some minor editing and clarification.

Comments welcome, of course.

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