NAND Flash Density Surpasses HDDs', But Price Is Still a Sticking Point (computerworld.com)

Lucas123 writes: With the introduction of 3D or stacked NAND flash memory, non-volatile memory has for the first time surpassed that of hard disk drives in density. This year, Micron revealed it had demonstrated areal densities in its laboratories of up to 2.77 terabits per square inch (Tbpsi) for its 3D NAND. That compares with the densest HDDs of about 1.3Tbpsi. While NAND flash may have surpassed hard drives in density, it doesn't mean the medium has reached price parity with HDDs — nor will it anytime soon. One roadblock to price parity is the cost of revamping existing or building new 3D NAND fabrication plant, which far exceeds that of hard drive manufacturing facilities, according to market research firm Coughlin Associates. HDD makers are also preparing to launch even denser products using technologies such as heat assisted magnetic recording.

Comments

Density is nice, but what about longevity?

[kheldan]

Have SSD's reached a point where they have a lifespan comparable to HDD's in the most extreme applications, though? For instance: Just had to replace the HDD in my DVR. It's dual tuner so it's buffering 30 minutes for each channel, perpetually. The HDD lasted for years; would a current-technology SSD last as long before it ran out of write cycles in the flash memory?

Re:Density is nice, but what about longevity?

[AnotherBlackHat]

OTA channels = 19.38 Mbps (max)
2 channels = 38.76 Mbps = 4.845 MB/sec
1 Terabyte SSD = 1,000,000 MB
1,000,000 / 4.845 = 206,398 seconds, or 2.3 days
Nand flash write cycle life : 10,000

Total life 10,000 * 2.3 days = 23,000 days or 65 years

If you don't like the assumptions, feel free to make your own, but I think it's clear that write cycle life isn't going to be the limiting factor.

Re:Density is nice, but what about longevity?

[nneonneo]

Let's work it out. A few years ago, TechReport ran an SSD endurance experiment to figure out how much punishment current-gen SSDs could take before failing. Their test setup essentially involved writing random data at maximum speed for 18 months straight. The results indicated that the worst SSD in their bunch, a Intel's 335 Series, wrote about 700 TB before dying, and the best SSD, a Samsung 840 Pro SSD, went on to 2.4 PB.

Various estimates say you can put between 60-75 hours of HD content on a 500GB drive, so, assuming the largest possible size, that works out to about 8.3 GB/hour. Since you're writing two streams, that's 16.6 GB/hour, or 145 TB per year. For the worst drive in the bunch, that's about 4.8 years of service (right at the upper end of your HDD's service life); for the best drive, it's over 16 years.

Keep in mind that these tests were all run on 250GB drives. Smaller drives have less flash to work with, and have to write over the same flash cells more often. Therefore, if you bought a 1TB drive, you can expect the lifetime to be easily 4x better (more if you're using a more recent drive, such as the Samsung 850 Pro) - 64 years of DVR recording should be more than sufficient.