Seagate Releases Hybrid Hard Drive

An anonymous reader writes to tell us Seagate has released a new hybrid hard drive. This new drive adds the speed of a solid state drive to the conventional hard drive. Originally designed for laptops this new drive comes in 80, 120, and 160 GB flavors and features 256MB of flash memory.

Comments

This is Great

[MrCrassic]

However, why did they only include 256MB of flash storage instead of a larger quantity like 2 GB or so?

Many people who exercise smaller flash storage options get flash drives larger than 512MB, so was it really that much more expensive to bump up the available flash storage a little bit?

Regardless, I look forward to the performance benefits devices like these will provide.

Re:This is Great

[Anonymous Coward]

I'm thoroughly confused now about using flash as a write cache. Isn't the write speed for flash something like 40MB/s for the expensive stuff, more like 10MB/s for the normal stuff? And don't SATA drives typically have better than 100MB/s write speeds? Are you typically writing the same stuff to disk over and over such that caching it makes sense? There is no predictive pre-fetch on a write either, as far as I know.

I see your point about not really needing flash for a read cache, since you don't need to keep it between reboots. But reading flash is still faster than from a disk, and since you don't need to keep it energized to maintain its state, you could have a cooler, quieter drive (and longer battery life) if you use flash instead of volatile memory.

Re:This is Great

[walt-sjc]

OK, my laptop has 2G of ram. Most modern laptops have at least 1G. While 256M is better than nothing, it certainly isn't much in terms of todays OS's and apps.

So here is what I would suggest... Put a card slot on there. Let me put in as much as I need. MicroSD cards are nice and small, but may be too slow, even the SDHC variety. I'm sure they could come up with something that would work well however.

Obligatory

[TopSpin]

Have 'they' solved the problem of the limited number of writes a flash device device can handle. If it's only going to last a few months and then wear out I won't consider it! Pity the poor fool that forgets to turn off atime updates.

Re:if it's a hybrid

[Anonymous Coward]

Furthermore, if they're going to have so little flash memory, why not have 256 MBs of cache instead... Seeing flash memory wears out and is more expensive.

Re:Couldn't this be done in software?

[morgan_greywolf]

But with USB 2.0, still potentially faster than a bare HDD, right?

I'd rather it allowed the drive to spin down.

[Joce640k]

Windows has this thing to let the drive go to sleep when you're not using it... ...except it never does because Windows is always syncing it or doing something. It never gets enough idle time to actually spin down.

If these drives could fool Windows into letting them go to sleep we might be onto something.

Like the Transistorized Vacuum Tube Radios?

[Cliff Stoll]

Around 1956, electronics makers began selling hybrid radios with both vacuum tubes and transistors. Emerson's vest-pocket portable model 843 used tubes in the rf stages and a pair of plug-in transistors for audio output. A 6 volt battery lit up the tubes and transistors, while a 67 volt battery kept the tubes' electrons jumping from cathodes to plates.

From Emerson's adverts: "Transistors are so tiny they must be seen to be believed. Transistors are so sturdy they won't break... They will last for life!" and give "greater power without distortion - full reproduction of voice and instruments, balanced tone quality, and greater power output with less distortion, not to mention low battery drain"

What other mixed hybrids have came along? Was there ever a hybrid horse and car?

Re:Like the Transistorized Vacuum Tube Radios?

[hcdejong]

By the end of WW2, aircraft engine technology was transitioning from pistons to turbines. The last generation of piston engines relied heavily on turbochargers and/or superchargers. Engines like the Napier Nomad and the Wright R3350 turbocompound can be considered hybrids: some of their output power comes from the piston engine, but some comes directly from the turbines.

Vista requirement

[ehiris]

Does that mean that the drives will not work with Linux?

Ahem, wrong cache type...

[fifirebel]

What you are describing is a write-back cache.
Brain fart? Or I misconstrued you?

Re:surviving falls

[bentcd]

The equations of motion can be found at
http://en.wikipedia.org/wiki/Equations_of_motion#Linear_equations_of_motion

In this particular case,
vf = vi + a * t
seems most appropriate (where vf is final velocity, vi is initial velocity, a is accelleration and t is duration of acceleration).
Assuming vf = 0 and solving for a, we get
a = vi/t (1)
Solving for t yields
t = vi/a (2)

"vi" after a 6-foot fall can be determined by using another of the equations:
vf^2 = vi^2 + 2ad
(where d is distance in meters, let's use 2 meters for 6 feet. We must assume that vi is zero.)
vf^2 = 2ad = 2 * 9.8 * 2 = about 40 m2/s2 (for simplicity).
vf = sqrt(40) m/s = about 6 (for simplicity)

For an object that travels at 6 m/s, we can use equation (2) above to learn how much time it must decellerate over in order to experience 900 Gs. 900G is (approx) 9000 m/s2 so we get
t = vi / a = (6 / 9000)s = 0.00067 seconds

So what we learn is that a disk that is dropped from 6 feet has a speed of 6 m/s as it hits the ground. Upon hitting, it starts deforming and if this is a reasonably linear process (which may or may not be the case) then a constant 900Gs throughout means that it took 0.00067 seconds to come to a complete stop.

Determining how many millimeters of the disk and/or ground got deformed during the decelleration is left as an exercise for the reader :-)