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Samsung's Hybrid Hard Drive Exposed
Erica Campbell writes "Samsung is preparing to release a new
Flash memory-assisted computer hard drive
that boasts improved performance, reduced energy consumption, a faster boot time, and better reliability. The new hybrid hard drive will be released around the same time as the upcoming Windows Vista operating system and will be one of the first hardware designed specifically to benefit from it."
What's so different about Vista that makes this drive benefit from Vista. Will the drive not work in Windows XP, Linux or Mac OSX machines?
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Sadly, I can't RTFA as the account has already suffered a slashdotting, but I have a question about this drive. Isn't there an upper limit to how many times you can write to flash memory before it ceases to function? Granted, hard drives wear out eventually, but unless this stuff is of high quality then the cache is going to wear out before the rest of the drive.
When the cache dies off, what happens?
It's designed for Vista, but I want it for Linux. How long until then I wonder?
Given Apple's strong relationship with Samsung (iPod shuffle+nano memory both come from Samsung, I believe- and I'm almost positive Samsung has supplied RAM to apple on+off since the golden olden days), what do others think about the possibility of this ending up in a Powerbook, er, Macbook Pro- and 10.5 being designed to take advantage of it?
Apple can be hit or miss with the latest and greatest- they took forever with USB2 (yeah yeah, firewire blah blah) and lagged behind a lot of the smaller laptop mafacturers with Expresscard (given there's next to nothing for expresscard, who can blame them?)...it'll be interesting to see if Apple thinks this is a win or lose technology...
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Excellent point. TFA has been Slashdotted so I can't see the specs without an undue amount of initiative on my part, but presumably if they put enough flash memory in, and used a proper distributive algorithm to make sure the same sectors aren't constantly written to - there might be little danger of this drive failing any sooner than a conventional drive.
I hope.
If Vista knows about the CF, why does it need to be on the hard disk itself? It sounds like all the heavy lifting is being done by Vista anyways. WOuldn't it make more sense just to use any CF attached to the system for this caching, etc, and use normal hard disks instead? That way adding CF to a PC would improve its performance, no matter what type of hard disks you have attached.
It's a tweaked XP not something newer than plan9 - it will probably swap it out to disk so you get a big page file and a delay while it is doing it, which is probably one reason this new drive will help.
Personally I think it is stupider than doublespace since memory limited programs like image editors are commonplace now. The annoyance of not being able to print for a couple of minute while the memory swaps out can come to everyone. It is paticularly stupid on the MS Windows platform where people typically only perform one application task at a time - you do not want the behemoth that is office in memory while you run some graphicly intensive thing or vice versa - you almost always only have one user with one desktop and one application being worked on.
The problem here is if we're talking about fully flash hard drives. If you bought two, one for backup (even in a ghost or RAID ghost setting), how can you rely on the fact that one won't die when it was written onto the same exact number of times, byte for byte, and used for the same amount of time? It's similar to current HD's, but these tend to not break at the same time.
Flash also can only be written onto so many times before it's rewriting capabilities start to suffer badly (don't remember the exact number, but this is when flash drives die).
We wrote a driver to read and write fat 16 flash drives for an embeded system. The testing for it wrote and read full speed 24/7 for two weeks before they died. I assumed that was because of the limited read write settings. Or is it possible the low quality connection was to blame? Doesn't really matter they were only used to transfer settings. As any one whos had to support them knows, they often just die for no apparent reason. I'm not convinced that this is a system I'd want my data on.
Well.. maybe. Or Maybe not. But Definitely not sort of.
I can't tell whether you're trying to be funny.
That is actually reason enough for me to re-think that whole Vista thing.
Has the ability to boot and run Linux off flash made you "re-think that whole Linux thing"?
With partial flash drives and eventually 100% flash drives, the last major component of computer hardware failure, namely, all of those closely moving parts in a hard drive, will be wiped out.
They'll be replaced by a medium that has a much higher MTBF for writes.
Oh yeah, and it'll be fast as hell, too.
Not really. Flash memory is not all that fast, and a lot of boot time is spent doing other things. On all my machines, most of the booting process is concerned with checking and initializing hardware.
Actually I think it's more like fixing software problems in Hardware. The situation in which this technology will improve access time is when you have to randomly seek on your harddrive. Unfortunately that is needed in Windows as there is little possibility to keep all your bootup files one after another in the order you need them. With Linux, however that is rather easily possible. You can create an initial ramdisk which the computer can load very quickly without much booting and then boot from it. Theoretically, if you have enough RAM, you can even load your complete system into it.
So now you essentially have to spend a lot of money (Flash and Patents!) on a technology which will, at most, give you an decrease in boot-times and will be obsolete once the power management of the drivers support Suspend to Disk or Suspend to RAM. Just look at Linux or MacOS 8 on an old clamshell iBook. You just close it and it's "Off", you open it again, and after very few seconds it's completely back again.
Out of curiosity, how similar is Vista's ReadyBoost feature to just mounting a USB drive as swap in Linux? Can you hot-unplug the drive in Linux if it's being used for swap? According to a FAQ on ReadyBoost I found, Vista will back up the pagefile to disk so it's not a catastrophe if you yank out the USB stick.
/proc/sys/vm/swappiness ?
And is there any setting in Linux to tweak to let the system know you've got a fast swap partition, other than simply monkeying with
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Sources:
http://www.techworld.com/storage/features/index. cfm?featureid=2814&pagtype=samecat
http://www.bitmicro.com/press_resources_flash_ss d.php
http://en.wikipedia.org/wiki/Flash_memory#Limita tions (yeah, yeah, Wikipedia isn't authoritative, but it's good enough)
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We did some basic research with Flash / HDD hybrids two years ago. As such disks weren't available, yet, we were using a real (Notebook)HDD and a IDE-Flash-HDD in parallel.
." in the root of a freshly booted system).
Our goal was to minimize energy consumption for mobile devices (i.e. not a lot of ram available for caching and the device is switched off repeatedly to save energy).
Using a very sensitive (time resolution wise) energy measurement device, we determined, that most energy was consumed by moving the heads into position. The difference was substancial: Around 0.63W for the HDD spinning idle and about 5.3W during heavy seeking (e.g. trigered by a "find
We decided to not use the flash as cache (flash is quick to read, but slow to write) and just put the relatively static metadata (directory structure, inode tables...) onto the Flash drive, but keep there files and data on the HDD, as each directory access triggered a expensive seek, but delivered very few data, compared to reading a file.
To simulate our mobile device we used a Linux-System limited to 32 ram to prevent the system from excessive caching.
We observed up to a factor 8 reduced energy consumption and as a surprising side effect a factor 6 increase in speed!
When increasing the available Ram, this advantage quickly vanished on repated benchmark runs, as the System appearently cached the directory structure very effectively. The first run after booting however still performed substancially better with our system, no matter the amout of ram. (And this was our target useage profile: Power on, search something, Power off).
As the code was an embarrassingly ugly hack to the ext2 driver and we envisioned trouble keeping the hdd with the data and the flash-hdd in sync, it was not persued further.
However with hybrid drives becoming available, it might be worth a more detailed analysis...
Really? What are the seek times on these 15,000 rpm scsi drives that out-perform solid-state devices, and where can I buy them?
It would also be ideal for laptop systems to save power...
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Enable swap on a flash volume. Install it in your grandmother's computer (256MB RAM, with the OS recommending 512MB). This is a real cause for concern, IMHO.
Not all wear leveling algorithms are created equal. In the worst case, your writes get hashed across a relatively small percentage of the cells in a particular flash part. Even in the best case, your wear leveling is still per flash part, not across the entire hard drive. Thus, unless the drive is spreading the cache load out evenly across all parts (in a way that is persistent across power cycles for the drive), it is really easy to construct a case where you would artificially wear one part of the unit faster and start getting errors when the drive is much less than 3-4 years.
The issue has been partially worked around, but the workaround is only sufficient for devices that don't have heavy write loads (e.g. digital cameras), not for a main system volume or even necessarily for a cache, though it -might- be good enough for a cache. Without a lot of implementation details, I wouldn't be comfortable with this feature on a hard drive. Thus, I'm not going to jump on this bandwagon until they've been out there for several years just so I can see the failure rate figures before making that call. I also want a guarantee that I'll be able to pull or install a jumper and disable the flash entirely so that when it eventually fails, the drive will still be usable, albeit slower.
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