Slashdot Mirror
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.
http://www.pcworld.com/zoom?id=138102&page=1&type=table&zoomIdx=2 -attached to- http://www.pcworld.com/article/id,138102-c,harddrives/article.html
Both hybrids, Samsung AND Seagate were not only more expensive, they were considerably slower in tests vs. a traditional harddrive. I understand the drive to be green, but I think I'm going to wait a few years before jumping on this bandwagon!
I found it, it was samsung over a year ago... http://www.infoworld.com/article/06/05/17/78429_HNhybriddrive_1.html?DISK-BASED%20BACKUP%20APPLIANCES
Actually, you have: http://msdn2.microsoft.com/en-us/library/ms940846.aspx (it's the first thing I do on a new installation of Windows)
I'm imagine they'd use this as a write-through cache. When you write data to the disk, it stores it in flash. Because a write-through cache can be quite effectively implemented in a ring-buffer (with reordering within a moving window for efficiency), you get perfect wear levelling without any complex controller logic. That means that it will work for writing 256MB times the number of rewrite cycles. Cheap flash has 10,000 rewrite cycles. My current laptop has been on for 30 days and has written 172.85GB to disk in this time. That gives 5.76GB/day of writing, or 23 complete write through the cache per day ignore, for now, that some of those were large linear writes, which would probably want to bypass the cache). For 10,000 rewrite cycles, with this usage pattern, it would take 435 day (1.2 years) to wear out the flash. This is, as I mentioned, assuming very cheap flash. Slightly more expensive stuff can get 100,000 rewrites, giving 12 years. If the mechanical parts of a laptop hard drive lasted 12 years, I would be very impressed. They should last longer with this kind of system, because it can batch writes a lot, and reduce the frequency of spinning the drive up and down. You also won't need to spin up the drive to read back data that you've only just written, which could help some poorly performing swapping algorithms (i.e. all of the ones used by 'modern' operating systems).
By the way, flash has a slight weird characteristic that you can write to it with a byte granularity, but only erase it with a block granularity, and it's the number of erases that cause the problems.
I am TheRaven on Soylent News
What is ReadyDrive:
http://www.microsoft.com/windows/products/windowsvista/features/details/performance.mspx
I'm summarizing what I learned from the German c't computer magazine, which has tested the various new technologies like ReadyDrive and others in Vista and also tested Flashdrives and Flash memory in general. Read the current issue of this magazine for in-depth analysis.
1) Pure Flash disks have only ONE advantage over harddisks: they are less sensitive to mechanical stress. In real-life scenarios, they don't safe power, and they are most definitely not faster than 2.5 inch drives. They ARE faster than 1.8 inch ones often used in ultra-mobile PCs, so there they indeed provide a benefit. For everyone else: especially write performance sucks compared to modern 2.5 inch disks, and read performance is at most en par. True, they don't need to position any heads so random access should save time - but according to the real-world tests made by c't that benefit isn't noticeable.
2) c't testers were very suspicious about how long Flash memory could survive as HD replacement where writing happens all the time, and yes, Flash cells have a limited lifetime, one cannot write too often. That's the theory. In practice c't testers were unable to make even the cheapest Flash USB stick show any sign of memory loss even after something like 16 million write cycles, when they gave up further testing because that's many many years of real-work usage. (pg. 104 of c't 21/2007)
3) Intel TurboMemory or MS Vista SuperFetch, ReadyBoost or ReadyDrive were shown to provide no measurable benefit AT ALL.
Suspicion of Hitachi and others seems to be that the current implementation in Vista isn't quite finished and SP1 should provide an update, and second the amount of Flash memory is waaaaaay too small.
Original article (German): http://www.heise.de/ct/07/21/100/
Here is an alternate article for the slashdotted original:
Having spent hours, days, years studying the effects of hard drive defragmentation, let me put the kibosh on 'intelligent defragmentation' here and now.
Defragmenting the files themselves gives about 20% of the potential benefits of defragmentation.
Defragmenting the file allocation table (FAT on FAT/FAT32 file systems, or MFT on NTFS file systems) gives the remaining 80% of the performance boost potentially given by defragging.
In the big scheme of things, it honestly doesn't matter whether the most recently used files are at the beginning of the drive, next to each other, or on opposite sides of the drive - if the file allocation table (or MFT) is sufficiently fragmented. Frag out the FAT/MFT bad enough over time, and simply defragging the MFT/FAT will make your computer run an order of magnitude faster.
Want the bad news? Windows doesn't ship with a FAT/MFT defragger (well through XP. Not sure about Vista.)
Only way I know to do it is with aftermarket software like Diskeeper (excellent product, BTW, 99% of the time.)
Glonoinha the MebiByte Slayer
No, that's not correct. Samsung is shipping hybrid hard drives for over half a year now (see, for example, http://www.engadget.com/2007/03/07/samsungs-hybrid-hard-drive-hhd-released-to-oems/).
Recently, they even blamed Microsoft for the poor performance of hybrid hard disks on Windows Vista (in German, http://www.heise.de/newsticker/result.xhtml?url=/newsticker/meldung/97021&words=Samsung%20Hybrid&T=samsung%20hybrid)