To avoid superparamagnetism, engineers have been increasing the coercivity, the field size required to write a bit, of the disc media. These fields are limited by the magnetic materials making up the write head that will soon effectively limit drive sizes utilizing longitudinal recording. Although additional capacities are still achievable, the drive industry will be moving to perpendicular recording technology shortly as longitudinal recording has basically hit the proverbial brick wall after being utilized for nearly 50 years."
I wrote a pretty detailed post on the anandtech forums about this a while back. You can check it out http://forums.anandtech.com/messageview.aspx?catid...">here" (I used to post under the nickname "klaviernista"). Considering I examined and issued a lot fo the patents that are the basis of seagate's perpendicular technology, I think I am more than qualified to speak on the matter.
Oh, and for the record, the "soft" magent under layer is never truly "written to" during the reocrind gprocess. The soft magnetic underlayer is made of a material that has magnetic domains which rotate easily in response to an external magentic field. When the write field goes across any given point in the medium, it induces the field in the corresponding point on the soft magentic underlayer to rotate perpendicular to the medium. The article is correct in saying that the result is a substantial increase in write field intensity, but neglects to mention that the fields of the soft magnetic underlayer to not remain oriented perpendicular to the media surface after the write field from the magentic head is removed, whereas the fields in the magentic recording layer do remain oriented perpendicular to the media surface.
The whole point of usuing a soft magnetic underlayer is to allow magnetic materials with very high coercivity to be used as the recoprding layer. Why do you need a very high coercivity recording layer in high density recordng media? See the post I linked to above and read the discussed about "intergranular exchange coupling."
if you want to have the seagate hard drive cross shipped where they send you a replacement and you return the defective one back to them they charge $25, considering the hard drive cost $99, that there is a ripoff. I had this happen to me with a 250GB HD that I bought last year, so I'll be spending my money with one of the others unless the deal is ridiculous.
SPCR uses 1 meter (aka 1000mm or 200 times your stated distance) to measure SPL.
"Each drive is measured for SPL one meter away from the top of the hard drive. Hard drive noise tends to be directional, the loudest position being directly over the top. SPL readings typically drop by 2~3 dBA/1m when measured from the side of the drive. The drive is placed on a soft foam to ensure that no vibration noise is produced during testing."
The there is an entire category of sounds you hear at 5mm that wouldn't be noticable from outside a case.
Take this quote from SPCR: "Consider the distance of Hardware.fr's recording microphone: 5cm from the HDD. This is a serious problem. There's no way the decibel reading can be accurate due to boundary effects. It's the same problem at storagereview.com -- not even relative differences are necessarily correct due to compression effects; the close proximity impacts every measurement similarly, reducing differences."
* One meter so that "nominal" volume, audibility, and sound character can be judged.
* One foot (or 30 cm if you will) to capture all the details from even the quietest noise sources.
The WD400YR and WD500YS seem very close to performance with the Raptor, but I can't find the WD400YR on pricewatch on newegg also I read about the WD drivers having a high rate of doa?
The Seagate drive has a performance advantage with the two 160GB platters. Anandtech is still ignoring the advantages of higher platter densities. Why is that? Platter density is one of the features I look at when purchasing a new drive. It's a good indication of performance when compared to another drive of the same total capacity. You have two 320GB drives reviewed with different number of platters and yet there is no mention of this other than the table. It's very odd.
Actually, as strange as it sounds, Gary is correct on the WD warranty. You can check it out for yourself at http://support.wdc.com/warranty/policy.asp">http://support.wdc.com/warranty/policy.asp. OEM (bulk) drives carry a 3-year warranty and retail drives carry one year with an option to add 2 more years (to 3 total) for $14.95. Enterprise drives like Raptor carry a 5-year warranty.
quote: Speaking of performance, the drive in our IPEAK tests was at times near the bottom of the group and usually trailed the Seagate 320GB drive except in the game play, general business, and applications were heavy read requests were prevalent.
I'm guessing it should be "...where heavy read requests were prevalent." Just a heads up.
Nice article, Gary. I enjoyed the background info on the two companies.
A quick question: Is it possible the str of the Seagate is higher because of a higher areal density due to having only two platters vs. the WD's three? Or have I overlooked something and need to go to sleep :)
I found strange how big a difference is in some bencmarks between one drive and the other (losing or winning). Anyway, each drive looks good value for money
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patentman - Monday, July 31, 2006 - link
To avoid superparamagnetism, engineers have been increasing the coercivity, the field size required to write a bit, of the disc media. These fields are limited by the magnetic materials making up the write head that will soon effectively limit drive sizes utilizing longitudinal recording. Although additional capacities are still achievable, the drive industry will be moving to perpendicular recording technology shortly as longitudinal recording has basically hit the proverbial brick wall after being utilized for nearly 50 years."I wrote a pretty detailed post on the anandtech forums about this a while back. You can check it out http://forums.anandtech.com/messageview.aspx?catid...">here" (I used to post under the nickname "klaviernista"). Considering I examined and issued a lot fo the patents that are the basis of seagate's perpendicular technology, I think I am more than qualified to speak on the matter.
Oh, and for the record, the "soft" magent under layer is never truly "written to" during the reocrind gprocess. The soft magnetic underlayer is made of a material that has magnetic domains which rotate easily in response to an external magentic field. When the write field goes across any given point in the medium, it induces the field in the corresponding point on the soft magentic underlayer to rotate perpendicular to the medium. The article is correct in saying that the result is a substantial increase in write field intensity, but neglects to mention that the fields of the soft magnetic underlayer to not remain oriented perpendicular to the media surface after the write field from the magentic head is removed, whereas the fields in the magentic recording layer do remain oriented perpendicular to the media surface.
The whole point of usuing a soft magnetic underlayer is to allow magnetic materials with very high coercivity to be used as the recoprding layer. Why do you need a very high coercivity recording layer in high density recordng media? See the post I linked to above and read the discussed about "intergranular exchange coupling."
jackylman - Thursday, July 27, 2006 - link
In the pulldown menu, accoustics -> acousticsSonicIce - Thursday, July 27, 2006 - link
Even with an extra platter to lug around, the Western Digital was quieter and cooler!madfly - Thursday, July 27, 2006 - link
if you want to have the seagate hard drive cross shipped where they send you a replacement and you return the defective one back to them they charge $25, considering the hard drive cost $99, that there is a ripoff. I had this happen to me with a 250GB HD that I bought last year, so I'll be spending my money with one of the others unless the deal is ridiculous.Mana211 - Thursday, July 27, 2006 - link
SPCR uses 1 meter (aka 1000mm or 200 times your stated distance) to measure SPL."Each drive is measured for SPL one meter away from the top of the hard drive. Hard drive noise tends to be directional, the loudest position being directly over the top. SPL readings typically drop by 2~3 dBA/1m when measured from the side of the drive. The drive is placed on a soft foam to ensure that no vibration noise is produced during testing."
The there is an entire category of sounds you hear at 5mm that wouldn't be noticable from outside a case.
Take this quote from SPCR: "Consider the distance of Hardware.fr's recording microphone: 5cm from the HDD. This is a serious problem. There's no way the decibel reading can be accurate due to boundary effects. It's the same problem at storagereview.com -- not even relative differences are necessarily correct due to compression effects; the close proximity impacts every measurement similarly, reducing differences."
http://www.silentpcreview.com/article631-page1.htm...">http://www.silentpcreview.com/article631-page1.htm... shows that the new audio recordings (not to be confused with the SPL Dba numbers) will use two recording distances:
* One meter so that "nominal" volume, audibility, and sound character can be judged.
* One foot (or 30 cm if you will) to capture all the details from even the quietest noise sources.
tuteja1986 - Thursday, July 27, 2006 - link
Western digital for me since i want a quiet and cool drive.crydee - Thursday, July 27, 2006 - link
The WD400YR and WD500YS seem very close to performance with the Raptor, but I can't find the WD400YR on pricewatch on newegg also I read about the WD drivers having a high rate of doa?AdamK47 3DS - Thursday, July 27, 2006 - link
The Seagate drive has a performance advantage with the two 160GB platters. Anandtech is still ignoring the advantages of higher platter densities. Why is that? Platter density is one of the features I look at when purchasing a new drive. It's a good indication of performance when compared to another drive of the same total capacity. You have two 320GB drives reviewed with different number of platters and yet there is no mention of this other than the table. It's very odd.evilharp - Thursday, July 27, 2006 - link
Check your "price bot" settings. Currently you list the following deals for a "Western Digital Caviar® SE16"I followed the Business Computing Network link (simply due to the crazy price) and it is for a 20 unit bulk purchase.
Booty - Thursday, July 27, 2006 - link
On the last page it should be listed that the WD has a 3 year warranty for retail and 1 year for OEM - you have them switched.Wesley Fink - Thursday, July 27, 2006 - link
Actually, as strange as it sounds, Gary is correct on the WD warranty. You can check it out for yourself at http://support.wdc.com/warranty/policy.asp">http://support.wdc.com/warranty/policy.asp. OEM (bulk) drives carry a 3-year warranty and retail drives carry one year with an option to add 2 more years (to 3 total) for $14.95. Enterprise drives like Raptor carry a 5-year warranty.Wesley Fink - Thursday, July 27, 2006 - link
Corrected.archcommus - Thursday, July 27, 2006 - link
I'm guessing it should be "...where heavy read requests were prevalent." Just a heads up.
Wesley Fink - Thursday, July 27, 2006 - link
Typo fixed.Zaitsev - Thursday, July 27, 2006 - link
Nice article, Gary. I enjoyed the background info on the two companies.A quick question: Is it possible the str of the Seagate is higher because of a higher areal density due to having only two platters vs. the WD's three? Or have I overlooked something and need to go to sleep :)
AkumaX - Thursday, July 27, 2006 - link
Nice article. We win either way!!! I'd rather go with Seagate though because I've had to RMA too many WD's in the past few years.Does anyone know of an app that measures HDD throughput (as in MB/s, read/write or both) in realtime?
Calin - Thursday, July 27, 2006 - link
I found strange how big a difference is in some bencmarks between one drive and the other (losing or winning). Anyway, each drive looks good value for moneyGooger - Thursday, July 27, 2006 - link
HDTACHPerformanceTest 6.0 (PassMark Software)
PC Pitstop @ PC Pitstop.com (requires internet explorer)
Googer - Thursday, July 27, 2006 - link
http://www.simplisoftware.com/Public/index.php?req...">http://www.simplisoftware.com/Public/index.php?req...AkumaX - Saturday, July 29, 2006 - link
Sorry, HDTach is a benchmark. I'm looking for something that actually tells me how my hard drive is doing at the moment