Flash Memory to Rival Hard Drives

Skal Tura writes "Samsung will start producing 16 gigabit Nand Flash chips this year, nudging the memory technology towards use in notebook PCs and maybe even edging out hard drives in some products in the next few years."

Comments

Gb or GB?

[TripMaster Monkey]

Some more information about the NAND flash memory can be found here.

One nice thing about this article is that it clearly explains the difference between a gigabit (Gb) and a gigabyte (GB)...something the article referenced in the story seems confused about.

From the article referenced in the story:

Samsung will start producing 16 gigabit Nand Flash chips this year...

Gartner estimates that 16GB Flash drives will cost from about $90...

And from the article referenced above:

Memory chips are measured in gigabits, or Gb, but consumer electronics manufacturers talk about how many gigabytes, or GB, are in their products. Eight gigabits make a gigabyte, so one 8Gb chip is the equivalent of 1GB.

Sorry to be picky, but I'm a stickler for detail.

Re:Gb or GB?

[Anonymous Coward]

Also some good insight on NAND here.

Re:Gb or GB?

[dnoyeb]

Of course there is also that 'number of writes' issue.

Re:Gb or GB?

[Belseth]

There's other uses than computers for large flash drives. I'm getting ready to pick up a Panasonic HVX200. They use a P2 memory cards as their primary recording medium. For 1080 your only other option is external hard drives. It's about 1 gig a minute at 1080/60. That translates out at 8 minutes for the largest card availible the 8 gig P2 which uses 4 2gig cards. Right now the cards are running around $2,000 but they'll drop fast as capacity goes up. They really start getting interesting when you can get a 32 gig card for $500. Even in today's market it isn't a competitive price for a hard drive but for video use given the advantges it would be very attractive. Cameras will help get capacity up and prices down so may be one day they'll make sense for computer hard drives. Everytime some one says we don't need more memory another use is found and need goes up. Terrabytes will start maxing out need for most traditional uses though. The problem will start to be organizing files since in the terrabytes most people wouldn't need to delete files. Video and graphics people are the only ones that may never be happy. Storing a single full res feature would still take quite a few terrabytes to store so if you do it professionally or are simply a serious film fanatic there's no practical limit to the storage that could be used.

Re:Gb or GB?

[Shanep]

Of course there is also that 'number of writes' issue.

True. However they can be used practically as system disks. I've been using CF cards for diskless firewalls for more than a year now. With OpenBSD I use softdeps and noatime and I've had no problems. I know of others who have done the same for years.

Re:Gb or GB?

[uberdave]

The computer world use of K=1024, although perfectly logical from a binary addressing point of view, is a hack of the SI prefix notation. Back in the not so long ago, some marketing dweeb noticed that 64K was actually 65536 bytes, and started selling computers that had 65K instead of 64. "Lookie here, Brandine", the uninformed consumer would say, "This here machine's got isself a whole extrie K".

The situation worsened when hard drives and RAM started into the megabyte realm. Is a megabye 1024*1024, 1024*1000, or 1000*1000? And if a gigabyte is a thousand megabytes does it mean 1024*1024*1024, 1024*1024*1000, or... well you get the picture.

Now as computer memories grew, so did their communications speeds. The telecommunications industry has always measured information in bits, as opposed to bytes. Not constrained by having to address these bits with other bits (as RAM and ROM manufacturers are) they did not adopt the K=1024 "standard", and followed the usual K=1000 meaning. So for them, a 56KB/S channel, meant 56000 bits (not bytes) per second.

So, with no standard for whether the b in Gb meant bits or bytes, or whether it meant 2^30 or 10^9, people started to get fed up. In the late 90's the IEC standards people got together and layed out a new standard (the "bible" one might say, if one were into puns). Lower case b is for bits. Upper case B is for bytes. Kilo (K)=1000, and Kibi (Ki)=1024.

Of course, it will take a few years for the world to adopt these standards. Old warhorses like myself (who remembers when BASIC had line numbers) will still be calling things by the old names for rest of our lives. Those of you who have never seen a rotary phone, or 8-track, or have never known a time without blogs have it easy.

Re:Gb or GB?

[Domini]

Yup, saw that too...

But then everyone (including you probably) also seems to confuse gibibyes and gigabytes anyway.

Slightly off topic:
It's similar to the markings on watches where the maker claims 100M water resistant, but this is a ploy, since the 100M does not mean 100m and the measurement only indcates 'safe to bath'. Most buyers don't know this and this confusion has also spread to other cheaper manufacturers...

Grr. Know your SI units and you can't get fooled!

Re:Gb or GB?

[k8to]

The redeeming fact is that the number of writes is now well over the number that people actually achieve in any normal application, including general purpose computing and even swap. Modern flash devices intended for general use are capable of distributing the phyiscal usage across the entire device, and the number of writes keeps slowly climbing orders of magnitude upwards.

Re:Gb or GB?

[nacturation]

Samsung will start producing 16 gigabit Nand Flash chips this year...

Gartner estimates that 16GB Flash drives will cost from about $90...

Where's the conflict? Flash chip != flash drive. Flash drives can often comprise multiple chips. Let's say we stack 8 of those 16Gb chips into one drive. How big is the flash drive going to be?

Re:Gb or GB?

[astralbat]

You can get laptops with 7200 RPM disk drives - they are known as desktop replacements. AFAIK, SATA is being used in the latest models now, even for the 4200 RPM drives.

Just don't expect their batteries to last long.

Re:Gb or GB?

[undercanopy]

uhh... i think you mean 12MBytes/s, but they're getting even faster than that.

I don't know what kind of flash drive you have, but mine runs a hell of a lot faster than usb1.1 speeds. I haven't tun hdtach on it but it but i just copied 87 megs of mp3s onto it in ~6 seconds, that's 14.5 MBytes/sec, or 116Mbits/s

looking back up i see you said flash card... dunno fi you think it matters, but my 512MB SD card is narly as fast.

gigawhat?

[Daniel Dvorkin]

Seems like they're playing fast and loose with capacity: "will start producing 16 gigabit Nand Flash chips this year" vs. " currently in products such as USB drives and digital cameras in capacities of up to 8GB." Correct me if I'm wrong, but doesn't 16 gigabits = 2GB?

Re:gigawhat?

[kf6auf]

It is my understanding that individual chips currently max out at 8 Gb; so t have an 8GB capacity right now you need 8 chips in your USB drive/camera/whatever. "Tomorrow" you will only need 4, meaning it should cost about half as much once the fixed costs are paid for.

Re:gigawhat?

[Mantus]

Your problem is the assumption that a device may only use one chip. There are 12GB (~$7300 USD) CF cards available and they use chips with less capacity than 16Gb. This will allow higher capacity/cheaper devices.

Re:I'm not surprised

[Jotaigna]

i dont know about long lifed, since a flash memory card has a limited number of writes anyway. This is because each one of the memory holding transistors has an extra insulating layer between the gate and the emitter, so electrons are "forced" throug, trapping the bit and therefore the data. There is only so many times (in the 10s of thousands) you can do this, and then is toast. If you use it as a hard drive with crappy memory paging, it will die soon.

Re:A Correction

[Fishead]

Ummm.... prolly not.

I don't know any specifics (but neither did your post, so we are even) but I build computer controlled devices that need to work in a fairly high vibration environment. Our current product runs off Win2K, and boots relatively quickly off a 2GB solid state Laptop size HDD.

We are building a new product that will be running Linux off a 256MB CF card. We are not quite done development, but it seems to run OK. It isn't working that hard though, just polling a USB control panel and outputting control commands based on what the user wants to do with a small amount of very simple graphics.

(disclaimer: I know very little about OS's and software. I am mostly solder jockey, circuit design, system installer, and a little bit of sales. I have been struggling to get my MythTV box working for over a year now :-)

Re:One Thought...

[BadassJesus]

Flashdisks are much more reliable then any conventional harddrive. They claim >5,000,000 write/erase cycles and unlimited reads. Unites States defence department is using them for reliability issue alone.

M-Systems (top flash disk producer) states this:
(copied from the website)

Top Reliability & Endurance
** 99.999% reliability
** >1,400,000 hours of actual (in the field) MTBF
** Embedded EDC/ECC, based on BCH Algorithm
** Data integrity under power-cycling
** TrueFFS® technology: bad blocks mapping-out and dynamic wear-leveling algorithms
** >5,000,000 Write/Erase cycles; Read unlimited
5-year warranty


Source link:
http://www.m-systems.com/site/en-US/Products/IDESC SIFFD/IDESCSIFFD

Re:One Thought...

[cdrudge]

MTBF isn't absolute. It's a statistical estimate. A hard drive may have a 500,000 hour MTBF. That particular model of drive wasn't tested for 57 years to see if it failed.

Any type of failure rate is also representive of the collection of all products being tested, not a single one.

Read the Failure Rate Wiki entry for more information.

Re:Flash is a complementary technology, not a riva

[Anonymous Coward]

I think it's worth mentioning that the bottleneck in reading/writing large files is an interface problem (usb et.al.) and not actually an issue with the ram. Currently the thing spinning drives have going for them is cost per GB.

10,000 writes/second for 13 years

[morcheeba]

That's 100k per block, not for the entire drive. The wear-leveling algorithms will make sure that even if you constantly re-write the same file, that part of the memory won't get worn out.

With a 512-byte erase block size, that is 419 billion writes. With a 4K erase block size, that's 52 billion writes. Use a 20GB drive instead of 2GB, and you'll get 10x the writes. And, the computer can warn you before the memory stops re-writing.

5 trillion writes is 10,000 writes/second for 13 years.

Re:10,000 writes/second for 13 years

[tootlemonde]

so if you are actually using most of your 20GB drive (which isnt very difficult to achieve), then you will wear out one section a lot faster.

Wear-leveling algorithms can take this problem into account. According to this article on Solid State Disks (SSD):

When a given block has been written above a certain percentage threshold, the SSD will (in the background, avoiding performance decreases) swap the data in that block with the data in a block that has exhibited a "read-only-like" characteristic.

Re:How bout NOR Flash?

[LOTHAR, of the Hill]

The traditional flash devices are NOR flash devices. They are by nature more reliable than NAND flash but are expensive to amnufacture. NOR flash devices can withstand more write write cycles than a NAND flash. BIOS flash are NOR, as are most of the solid state flash drives used in telecom and aerospace. This is why NOR flash is marketed to embedded/industrial customers and NAND flash is marketed to the consumer market.

Re:How bout NOR Flash?

[hyc]

NOR flash is extremely slow for writes. This Samsung appnote
http://www.samsung.com/Products/Semiconductor/Memo ry/appnote/onenand_features_performance_051104.pdf
compares I/O performance of the various technologies (the chart is on page 28, so scroll down...)

For their test rig, NAND flash yields 8.8MB/sec writes vs NOR at 0.14MB/sec. That's why NOR flash is only used for BIOS memory and other things you don't have to rewrite very often. On the flip side, NAND flash gets reads at 16.5MB/sec vs NOR at 23.9MB/sec (or 108MB/sec, presumably in some kind of burst mode - that part isn't explained).

If their OneNAND performs as well as they claim, I could see using it for a boot drive; 68MB/sec read would be fine there, 9.3MB/sec write would be ok as long as you weren't paging to it or doing much of anything else. Linux would run pretty well with those parameters, its buffer cache is good at absorbing and deferring writes; Windows 2K/XP's memory manager/cache manager purges pages too aggressively though, which would make the write throughput a serious system bottleneck.

Re:How bout NOR Flash?

[Kuj0317]

the number of transistors required to make a nand gate is less than the number required to make a nor gate. Therefore, nor would offer no benefit, while requiring more tx's (higher power consumption and less chip density)

I know the diff -- and I missed it in the article.

[CFD339]

For me it was very helpful to see it posted -- I'm very much aware of the differences but missed the word gigabit in the article when I quickly read it. Reading that post was in fact "inciteful" to me and if I'd had mod points at the moment I'd have marked it so.

Re:One Thought...

[gnasher719]

'' MTBF isn't absolute. It's a statistical estimate. A hard drive may have a 500,000 hour MTBF. That particular model of drive wasn't tested for 57 years to see if it failed. ''

Also important: Products like harddisk have a limited life. That harddisk with 500,000 hour MTBF will wear out after five years or 50,000 hours; no way will it last 500,000 hours. The MTBF only means: If you buy 500 harddisks and run them for 1000 hours, you can expect one to fail.