美国海淘    剁手星期一： SEAGATE 希捷 Backup Plus Hub 8TB 桌面硬盘（STEL8000400）约￥1260

drive, and they said "Unfortunately, we do not have this information available." Ha ha! Their reticence is understandable, the more common PMR (Perpendicular Magnetic Recording) technology is generally preferred. The prices of these Backup Plus Hub drives are less than Seagate's bare PMR drives of equal capacity, which also supports the idea that the Backup Plus Hub series is SMR.SMR technology allows more physical bits of memory in the same space without decreasing the size of the bits.Advantages of SMR-- Fast burst sequential writes are possible due to higher density and allied technology.-- Larger drive capacities in same-size enclosures.-- Cheaper to produce in large capacities.Disadvantages of SMR-- Slower random writes. SMR drives use large write heads relative to the width of the tracks of bits, so writing one track affects the next tracks of bits too. This limits SMR drives to sequential writing, where the next tracks don't matter. To do random writes (such as changes to data on the drive already), data must be arranged sequentially in cache, by the drive in this case, and entire sections of the drive must be rewritten sequentially. Some of this can be hidden by the use of large cache on the drive, believed to be 20 GB or more on Seagate SMR drives. Data can be written quickly to cache and then rewritten more slowly to another part of the drive.-- Highly variable sequential write speeds, due to the particular ways the drive manages where to put data.Read speeds aren't affected as much. The consensus about SMR drives is that they're well suited to backup use, which is reflected in the name of this series of drives. They probably aren't as suitable to use as a main drive to run a computer from, and are generally not recommended for RAID configurations (which wouldn't be likely uses for a single external drive anyway).Real-life speedsThe 6 TB version of this drive hasn't been tested by professional reviewers, but the 8 TB version has tested very well in standard benchmarks in numerous professional reviews, often well over the 160 MBs maximum rate claimed by Seagate. It's been more variable in practical use. I'm unable to test it myself with a USB 3.0 connection, but one professional reviewer who did got an average of 72 MB/s for a write of a little under 90 GB of files. That's a little over 20 minutes. (A customer review here--Pacific coast again--gets a similar 75 MB/s.)Differences between Windows and Mac versionsAccording to Seagate, the only differences between this Windows version and the Mac version of the Backup Plus Hub series are the initial formatting of the drives and the cosmetics of the cases. The formatting can easily be changed at home, so buy whichever drive you please for either OS.System requirements-- Windows 7 or later-- Mac OS 10.7 or later-- for Mobile Backup app: iOS 8 or higher, Android 3.0 or higherOther points-- Doesn't run too hot. I've seen measured temps of 100 and 113 degrees inside, which is fine for a hard drive.-- A little noisy when operating, not any worse than most computers.-- No fan, has passive cooling through vents on the bottom.-- Includes USB 3 (or 2) cable, type A to micro-B.-- 2-year warranty.

When you unplug the ethernet cable, it goes thru a busy few minutes with disk activitiy. Then after it "calmed down", I noticed that such semi-cyclical head activity is still going on. At that point the only possible intervention to drives can obviously be coming from NAS operating system (DSM 6.1.3-15152 Update 3) and/or these 3 "packages" running on that NAS OS:-Universal Search (can't disable)-File Station (can't disable)-Media Server (can uninstall)So in theory either NAS OS or one of these packages can be "polling" the drives cyclically. Otherwise, such cyclical activity must be coming from drive itself. I checked a bit more online for that ST8000AS0002 drive. Looks like Seagate part no is 1NA17Z and firmware version of my drives is: RT17 . Seagate website informs that; "No Newer Firmware Available / A field update is not available" (I guess they don't want to give users the ability to change firmware - potentially discovering built-in "NSA code"! (as discovered by Kaspersky few years ago)).Since user Christopher K. reported silent NAS operation of his same drives; the chances are that they might have never firmware. Or it could be purely because of NAS OS.I update both OS and packages on my Synology NAS as they become available. So it might be theoretically possible that one such update (which coincided with me installing these new Seagate drives) could be the reason behind such cyclical activity. But I noticed this nuisance immediately after upgrading to these new Seagate drives. So I still reasonably think that it's being caused by the drive itself (whether SMR structure or firmware level).On my test, next I plugged back CAT6 cable to my NAS. So now it's hardwired to my router (Netgear Nighthawk R6700); another potential source of external polling to the drives. Again after few more minutes of "calming down"; already existing activity level of drives didn't change. So the router is not guilty.At that point my hard-wired desktop PCs are off. I turned on one of my Win10 PCs (running Kaspersky Internet Suite); still same activity level on those Seagate drives.So my conclusion is; I still think that these drives (at least the ones I have - with potentially earlier firmware) are not able to "sit quite" in my given NAS. The only absolute proof will be when I upgrade them in the future (it'll be a non-SMR drive). If the new drives will be as quite as my earlier (non-SMR) Seagate drives; then I'll know that the reason was those drives after all...--------------------------------------------------------------------------------------------------------------UPDATE: In my NAS; drive heads seek in irregular intervals (about every 5-15 seconds), even there is no user read/write activity going on. Drives might be refreshing their buffers or something. Previous Seagate models (non-SMR type) were not doing that.Other than that extremely audible nuisance, this non-stop mechanical activity might shorten life-span of drives. I'll update if they fail prematurely. I suggest that you avoid this (and any) drive that uses SMR technology.--------------------------------------------------------------------------------------------------------------Inside the unit is a Seagate Archive HDD v2 ST8000AS0002 8TB 5900 RPM 128MB Cache SATA 6.0Gb/s 3.5" Internal Hard Drive.I needed the internal drive. This external unit was cheaper than buying the bare drive. Plus I have an extra USB3-to-SATA board with power adapter.This drive uses SMR technology; so it's supposed to be slow (not to be used as system drive - for archive purposes only).I replaced one of my aged NAS drives (also a Seagate 4TB Barracuda ST4000DM000 which reliably served me about 4 years - 24 hrs) with this new ST8000AS0002. Both drives have 5900 rpm speed. New one uses SMR technology, old one does not. New one runs at 100 F temperature (measured by my NAS) - old one at 90 F side-by side in NAS enclosure (fan cooled).I use my NAS strictly with ethernet cable (although it has wi-fi option; it's a joke and I disabled it after trying it once). So with old drives (in parallel writing RAID mode) I was getting 75MB/sec transfer speed. Surprisingly with one new drive (other 4TB still keeps running after 4 years) I still get the same speed. So speed of this 8TB SMR drive is totally acceptable to me. Much more than archiving speed, I can consistently stream HD movie with that 75MB/sec hard-wired ethernet connection.For those who are thinking about doing the same; opening the case is pretty much destructive (read: your warranty for whole unit is void). Interestingly; I checked warranty status for bare internal drive : Seagate web site informs that "the unit was sold as a system component. Please contact your place of purchase for service"... So after all; directly buying an internal drive (and paying a bit more) makes better sense for warranty purposes.I'll update later on about longevity of the new drive.

d about 90 days ago, but was not used for several weeks; and thereafter, usage was light (for example, Time Machine backups for a couple laptops). Then after about 2 months of use it died last week. I attempted to locate another adapter to confirm that the adaptor was not the issue, but was unable to locate the unique one that comes with this unit (Seagate power supply: 12V 3A / barrel outside 5.5mm inside 2.5mm center positive). Therefore, I contacted customer service regarding the matter and they asked me to purchase one to test their drive. Yes, they wouldn't send me a replacement adaptor to test their product, but rather wanted me to purchase one. So with that support interaction, I elected to return the unit under their product warranty coverage. That is when I was informed that they only warranty the product and DO NOT cover sending the product back to them to replace. And BTW, their warranty replacement unit will be a refurbished unit, not a new one ... another surprise in warranty coverage. Today I mailed the drive to Seagate, and my wallet is another $20+ dollars lighter ... YIKES. Therefore, due to the experience of the unit's life (60 days with light usage) and Seagate's support/warranty, I have to rate this product a ZERO!