On Thu, 12 Nov 2020 22:56:11 -0500, Paul wrote:
> The 15mm thick 2.5" drives for a start.
>
> There's no reason for them to have a SATA connector,
> because they're not to be offered to the retail
> market as internal drives.
>
> Those are an orphan product used only within 2.5"
> external drives.
Hi Paul,
I appreciate that you're always three things many others can't be:
1. Detailed
2. Knowledgeable
3. Purposefully helpful
(while I only own the first and last traits, and lack the middle).
This is good to know that the 15mm-thick 2.5" drives will likely never be
SATA, which means you can't as easily "shuck" them when needed (although
you may not need shucking as much since they also do not require an
additional 12VDC power source like my 8TB 3.5" Seagate needs to run.
> The 3.5" drives are still "suitable" for usage in
> external housings or as raw drive mechanisms for
> the retail market.
>
> The 8TB drive in question, has a visual hint. It has
> two USB connectors on the front. And one USB on the back.
The 8TB Seagate has 2 output USBs on the back & 1 USB 3.0 input in front.
o 8TB Costco Item #8888881 P/N 1XAAY5-570 (STEL800401 on sticker)
I get it though that it's a "visual hint" that there must be a "powered
hub" somewhere inside since each of those output ports has to fit the USB
standard on simultaneous output current sourcing.
> This suggests a separate PCB to house the hub function.
> It makes sense then, to also have a SATA to USB function
> on the (separate) adapter board too (hub chip, converter chip).
I understand the logic you present and do not disagree.
o Thanks for breaking it down into its component parts (which is helpful).
(NOTE: Logic needs to be stepwise; if steps are missed, it's "intuition",
and intuition is almost always wrong (read quantum mechanics for why).
Note below... understanding _each_ sentence you write takes me a while as I
have to look up each of the things you say (unlike those moronic Apple
Apologists like Alan Baker who never seem to look up _anything_ ever!).
> But before getting too excited, the seagate drive is:
>
> 1) SMR (the good kind is PMR)
Here you go again using those damn big words on me! :)
Looking up what the heck SMR & PMR are...
o What are PMR and SMR hard disk drives?
<
https://www.synology.com/en-uk/knowledgebase/DSM/tutorial/Storage/PMR_SMR_hard_disk_drives>
o Perpendicular Magnetic Recording (aka Conventional Magnetic Recording)
o Shingled Magnetic Recording (offers greater areal density)
Hmmm... who knew about "idle time" being important?
"When the HDD becomes idle, it will enter a reorganization mode where the
old bits of data on the original track will be erased and made fully
available for future use. This reorganization mode must occur to
completely delete tracks, making the idle time essential for an SMR
drive."
Bearing in mind that these disks will not be used frequently, the question
is how that matters over _elapsed_ time of decades from now (the actual use
of a "backup" disk is, oh, let's say, oh, about, um, oh, one hour a month,
let's say, over a 25 year period - so that's 300 actual hours in 25 years
(let's make it 500 hours in 25 years just for easy numbers).
I guess it simply means that we can _double_ the time we hook up SMR
drives, such that the idle time is equal to the running time, which doubles
that spinning time to 1,000 hours in 25 years.
> 2) 120MB/sec ("hello to year 2007" or so, this is the SMR rate)
Hi Paul,
Unlike the Apple apologists, I'm all about "logic", where I don't think
read/write time should matter all that much for a _backup_ disk, do you?
It's a _backup_ disk, right?
o All I should care about is what matters to a _backup_ disk, right?
To me, the key thing that matters is the data must be available
25 years from now - and that the disk can be used an hour a month (or so)
to easily back up the data - and that it must hold a _lot_ of backup data.
Looking at this article on SMR speeds from Western Digital:
o <
https://hddscan.com/blog/2020/hdd-wd-smr.html>
"it is not recommended to use SMR drives for applications
with significant load"
But this is a portable _backup_ drive.
By definition, the "load" on a portable _backup_ drive is puny, right?
o The thing spins for 1,000 hours in 25 years, max, right?
What seems to me to matter a lot about _backup_ drives is elapsed time.
o Will your data still be accessible to you in 25 years from now?
> 3) *Could* have aggressive spindown behavior.
> Requires a tester to test. Without spindown the
> drive could overheat.
I can appreciate overheating, but we have to always keep in mind these are
external _backup_ disks which have a known amount of cooling given they
basically sit temporarily on the desktop while being used an hour a month.
The key question for backup disks, particularly in light of the fact we're
storing precious photos of the kids and grandkids, is whether those photos
will be accessible in 25 years from now, due to technology changes and
storage issues (and the simple fact that fewer parts is better and more
interchangeable parts is better from the standpoint that we don't know if
we'll even have the cables handy in 25 years).
In summary, if we store our own photos, which of the two Costco
hundred-dollar backup drives are better for eventual use in a few decades?
--
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