Everything? to know about external HDD.(or  SSD)          

This device is used for 2 reasons, Backup data or to Clone a HDD to HDD or to SSD.  ( things not applicable)
Normal behavior is.

The external box, or enclosure, or DOCKING STATION ,  or just  a clone cable.  (I will do Basic boxes only here cover all failure modes.  I will call them HDD BOXES. (the BOX from now on).
Do know that some folks avoid all this and use cloud storage. (or like me, I use web servers to backup key data and the below both)
The 2 big complaints on externals, is  #1  it is too slow, or #2  it's dead.
eSata hints?

External HDD Problems? 3.5" only.
The top 3 reasons for failure here are: (I do all ways later below in 2 more lists, long and shorter)
  • Thinking XP has  future, gee, it's been dead for 3years and now so be VISTA 2017 this  Spring , MS shut it down to, and may fail for dead USB ports now. (PnP is dead now)  Be sure SP3 is installed in XP or its hopeless.
  • Expecting that Laptop 100ma USB 2 can run a huge HDD. (or for that matter 500mA USB ports.) It can't. Get a case with a 12vdc 2.0 amp power pack or buy a SSD that only needs  0.1amp to startup.(or less)
  • Thinking Windows, can read your HDD that is formatted for Apple or 100s of other ODD ball computers. I't can't  , solution is easy, erase the drive and format it to NTFS.
  • Thinking that GPT forumatted HDD  (say under W10) can be seen by older windows. It can not. (see proof here)
  • The HDD box, missing a 12vdc,pwer  pack means the BOX needs  5vdc (usb Vbus) power to produce 12vdc power converter to run the drive motor.  (this is the 2nd limit on motor current and easy failures)
Did you know XP is dead,  and VISTA now, and what that means,? I means your new BOX with that new sexy chip inside is not supported under XP at all and now VISTA
Plug and play is now dead at MS XP and MS VISTA, so why would you expect this to work.  (call you BOX vender and demand XP support ?, see how far you get...?.)

 What to buy is easy: (DIY?)
  1. A BOX that has USB port and cable or.
  2. An e-SATA port and cable.  SATA-III is best, for now and the future and for sure using any SSD.
  3. A 12vdc power pack rated at at least 2.0Amps or more.  (the startup current can be very high, 1 to 2amps or more as seen below.)
  4. Some Green drives, are only 1.2amps on the 12vdc bus,  3.5"  (about 1/2 power) starting up and getting to max RPM. (eg: WD10EZRX by Western Digital)
  5. Some boxes now do both 2.5" and 3.5" drives, make sure it can be locked down so the drive does not fall out easy, sata ports do not have locks, so the drive must be clamped down to be secure.
  6. If using a 2.5" drive make sure your USB port can handle a full 1amp startup current. (or use and SSD) 

Do know what many OLD (vast) Laptops only can source 100mA(say 1/10th amp)on any USB port. RTM read your product spec. and learn what it can do. (my desktop does 500mA on USB)
No only that but some PC can do 500mA only when software nogoitated and newer PC can do up to 1.8Amps and 2.0Amps and now in 2015 ,USB-C and 5amps.  (5x12v =60watts) and that 65watt power pack is not going to make that happen.  The super set of Class C is Thunderbolt and its logo and special new cables, and 2 direction power flows.
Know that some PCs the USB port power is shared by other USB ports, so if you have other power sucking devices there, guess what,  your HDD port is very limited on power, due to that 1 fact.
Current seen on a scope with a CURRENT probe.  (amps). This is 3.5" drive and at the 12vdc power wire )
From Seagate white pages, that ramp down is the RPM coming up to speed. Those tiny spikes is the head servo moving.

As you can clearly see 100mA USB current will never handle 2amps above load, nor will 500mA rated USB ports, Unless behind it is  HUGE 1000uF cap. (that can't fit there on a laptop, but can on any Desktop)
In fact, the offical USB spec. even tells you how to to ride through such a spike. (ways and means in the POWER CHAPTERS)

Know that the USB  ports can go to sleep. (it's programmable by you in Windows) So turn it off I this feature gets in your way.
The beauty of these boxes below is they can run on any PC made with either usb or e-sata ports.

These 3.5" Esata enclosure  (by ROSEWILL) I Have many here that are old. (it's slow USB1.5, 187MB/sec. Using the old slow JMB351 chip from Jmicron inside.
A far better box is here USB3 +esata port.by VANTEK (the higher price is justifed) @$35

If your PC only does USB2 speeds?, buy the super speed  card to upgrade that form same folks here.

 This is my DT USB port, It can not in anyway ,handle the startup current of my 1TB HDD. not possible.!!! (it's only 1/4th the power needed) But sure a SSD will sing like a bird here.
See that motor run, it uses lots of power ! and start up power is max.! running power is 10x less.

Show and tell #1, here is my 2009 year BOX.
Below is my FANTOM(tm) Drive.  USB2  With Initio chip #Inic-1611L (Data transfer rate of up to 60 MB/sec on USB side, 150 MB/sec on SATA side.)
Once can simply drag copy files to back up at anytime you want, or use any backup program you please, (a near endless list)
This chassis is not going to run fast with SSD, with USB 2 chips here, so do learn that the CHIP inside is a top thing to learn. (I opened mine and read the chip laser marked lable to see what I got) No secrets.

There are docking cables and docking stations, for any drive you want, and speed class as seen here.(as low as $18 cheap USB3 rated)
Keep in mind that I only run my 15,000 RPM drives in a fan cooled case or it WILL OVERHEAT..
No lie a fan cooled BOX is the best to own if planning on using an form or hot running high RPM hard drives, but sure if using SSD you do not need any fan ever. (or 2.5" slow cool drives)
Do learn that most boxes sold have no data sheet,  in almost every case the sheet presented is useless to read, no important details at all, just USB 3 or eSata stated, no data rates stated. 
There are ready to run boxes using 2.5" drives, that do run at 500mA USB ports, that is no lie. ( both SSD drives and green drives)
 THE NEED FOR SPEED, lies ,1/2 truths and the seems like a hype thing.  (Know  that the bus can do 600MB/sec. but no 1 Hard drive ever goes that fast. (heck most HDD can't  even tax the 300MB/Sec.
Now the speed confusions, first off MB/Sec is megabytes per second and mb is bits. not bytes.  MB is  not  the same as mb , best is to use full English, MegaBytes, is MB.
The speeds you read are (under perfect conditions , means no software overhead 20% is typ. and software does in fact slow it way down. (in fact in all cases!)
USB2 60MB/sec. (as you can see your old laptop is going to have very very slow external drive if ANY KIND.  about 10x slower, 10 is huge number to humans, (felt /seen)  there is also a USB2 super speed , 3x faster.
Watch out my LT has 2 and 3 ports, do not use the wrong ports they are NOT THE SAME, on my Elitebook.
USB3 640MB/sec (10x faster. usb 3.1 cuts overhead to 3% (bottom layers of OSI model)
SATA 1 = 150MB/sec  
SATA 2 = 300  (see any HDD ever hit this limit? here?)
SATA 3 = 600  (aka SATA III)  no single HDD goes this fast, how can it?, even 15,000RPM drive can't.   learn how head seek times slow data flows..,  and all this is easy to understand, SEAGATE has VAST WHITE papers to read, please do and learn.
and SATA 3.2 = 1969MB/sec (wow)  (over kill this is now.)

What does that tell you? answer: it tells you need to know what chip is in that BOX,  is it a USB3/SATA3 chip , yes or no.?   HARDWARE MATTERS the CHIP there MATTERS.  SSD will need USB3 for sure.
The fastest speed you will ever see on HDD is from its internal CACHE ram.  if the head must jump a cylinder (track) oops, huge delays.  (bench marks are complex, for every one you show, I can invent other to make your drive look worse)
It's like car, it's fast but not so up hills nor for sure in Denver., and worse yet a 15,000 ft altitudes. (or wet roads)
What amazes me is folks can't under stand hardware and software, (simple issues here)
Rule one, you can't go faster than the HDD lets you, ever! , well unless a lucky short cashe hit.  
Ive heard of a hard ware sequencer, this is device that runs 10x faster (using rules of NIST.gov) to measure say 1 USB/SATA chip.
Imagine at test box with 10x clock and HS ROM full of some data and this box sends data into said chip (DUT device under test)  and then you measure output rates. (and then do that test back and forth to get turn around delays in the mix) Yes.
The next layer is the driver, this is software layer #1, of the 7 layer model, (btw some OS use less layers on purpose and CAN !, These layers all cause HUGE DELAYS.  (some more some less but all do)
What matters is total throughput,  in all cases, and can be as low as 50MB/sec or up to 248(R). (near) Note it can't tax even USB2(300) see? in 2017. Seagate Barracuda Pro 10TB (2016)
The hype is always prefaced with the words theoretical speed, there is no such word or thing here, my god there are now 14 OS by Microsoft , linux, and a vast numbers of USB chips and there matching drivers.  ( ever see a spec ever ?on a driver speed, no!) What does work is THROUGH PUT.
Stop reading hardware spec's then thinking that is what you get, STOP it. Those numbers only work with NO SOFTWARE AT ALL .
Try hard to know that the chip maker have no clue as to your applications,  nor any idea at what software you will run, if any at all.  (the spec.'s see are pure hardware spec. nothing else for these facts)
Ever seen a hardware only cloning devices that runs at full bus speeds, using this chip? (learn that you can use pure  fast harware logic to transfer HDD sectors. , A to B)
What matters is bench marking, learn to read what your device does on operating system X. Version Y, driver Z. (the seven layers can be what ever.)

They measure to the true speed. This is not hype, as this guys says. Its a  hardware spec, and has nothing at all to do with SYSTEM TOTAL performances.
USB 2 drive 32MB/sec as slow as... and 100MB'sec on USB3 HDD.  sustained, not some silly CACHE hit deal.  READING MEDIA cylinders. (we all know SSD go super fast even near 1000MB/sec. 1/2 that is PAR.
Last is those with horrible slow HDD, some slow RPM old LATPTOP 2.5" drive and expecting speeds go faster on USB3,  sorry you need to learn first where the bottleneck is first, in this case its the DRIVE ! (a cheap slow drive,ah but uses less battery power.. no  lie.)
Again the interface speed is not through put speed, (random read/writes and full 7 layer OSI model combined)
The hardware layer and 7 software layers, together they form Through-Put.  (end to end , R/W performance) its not hype it's electronics and software working as a team. (btw the chip maker never once lied to you, ever)

Normal behavior: 1 example, W10...
New HDD, 3.5"  Seagate,  virgin new, zero format of any kind !!
Both cables connected, power and USB.
I turn it on and hear the USB dingo, sounds. (usb not dead)  hear drive spin up and feel it  fight me ! (like a fast flywheel, as I hand turn case slowly) the effect of centrifugal forces.
I go to diskmanager here.  (CP + Administrator tools + computer managment then disk manager.)
The new disk window pops autotmatcially for the disk 4 seen here, and I pick MBR and ok.
It warns you that  GPT fomatted disk are not seen by older Windows. (see link above for that fact)
I then go to disk 4 (or what your is) disk and right click the disk area and then pick new simple volume wizard (it's    formatter)
I click next  pick a drive letter and it formats the volume :
Now "This PC" , file explorer sees the disk full time. (connected and powered on.)

If the "so called new  drive" can not be seen by diskmanager, then  before condemining the drive, erase it  with any live  booted Linux  or   free  DBAN disk. (boot and nuke,etc)
or use Linux to format the drive to NTFS the whole thing.
Remove all HDD/SSD drives containing data before running any DBAN program.  (or risk data loss) It's easy to forget what is difference from disk 0,2,3, or Hd0,hd1,hd2, etc..

My hard drive external failure list: (dead)
  1. The old pathetic laptop can not spin up the drive , or for sure any 3.5" drive (this is power issue)  If the hdd can not be heard to spin up to full speed, bingo power issues.
  2. The old PC runs XP and the USB ports  are dead (what's new there, upgrade to w7)
  3. The BOX (hdd enclosure) is turned off, or the power pack to it dead, or unpluged or the wrong one is used, 12vdc, 2Amps (min).
  4. Forgot to format it? forgot to assign it a DRIVE LETTER? (if not explorer can't see it , only Diskmanagment  can.(if blank or MS formatted, not if APPLE formatted)
  5. Has the wrong format? Windows can't see Apple or other alien formats so erase the drive and start over, in disk manager. (or inside another PC) !
  6. Does the HDD fail inside any other  PC internal SATA port (power must be connected too) Yes, then it's a bad HDD. if not fail there, then you have issues with your BOX (enclosure)
  7. Does USB work but e-SATA fail, yes, then e-sata cable inside PC fell off or the BIOS has this port SHUT OFF,  (look in your BIOS pages, and find that) ( if your PC allows hot swapped e-sata , like mine, this too needs to turned on in BIOS and windows too. By the way , most laptops the Esata cable is missing 12vdc making 3.5" HDD dead (but not 2.5")
  8. Both USB and e_SATA fail , either power issue or bad HDD, test HDD in a PC directly , internally.
  9. If only USB fails did you try all USB ports and a good cable.? warning some USB ports can't do USB3 and some can't do over 100ma current, so use the power pack and win. 
  10. Each inclusure running on USB only, no 12vdc pack , only works on  2.5" drives or  SSD,  3.5" need powerful 12vcd to run.
  11. So if the Drive can not be heard do spin up or you hear it clicking over and over, try using a real BOX with a real 12vdc 2amp or more power pack and now see the motor start every time. 
  12. One other trick is to boot to Linux, using the great and free Knoppix v7 up, live DVD (or USB stick) can you see the drive now? can your format it to NTFS; sure you can. (or erase it first then format it to any windows spec format only) Linux sees all formats (hint hint !) learn to use LINUX live boots media learn the LIXUS see things Windows, can not see at all !
  13. Running XP and the USB ports are inoperative ?  XP is dead, no plug and play at MS,  XP has grave difficulties with USB and 10 times worse lacking the SP3 UPGRADE.

The power used on SSD   can be 100 times less than any HDD made. DIPM turned on Device Initiated Power Management, even less. 0.07watts on mine.
The difficult drives to spin up are here, from hard to easy.
15,000 RPM  3.5" HDD
all 3.5" drives,  need near 2 amps to startup. (same with Hybrid drives they suck same startup currents)
2.5" are easy but not on old laptops. No HDD of any kind likes old laptops and the weak 100mA power availiable.  The 2.5" uses 5vdc to run the motor , 12 volt pins are not connected.
SSD are childs play; there is no motor to spin up.

Most USB3 devices are backwards compatible. So in most cases this is never a problem.
If all things seem to fail.
The the offending drive HDD is still dead, then put it in any PC, and erase it or even better erase it using Linux live boot CD.
(many HDD are preformatted, or are used,  my Seagate drives all come totally blank, no format at all, and Windows has no problem with that.)

This page does not apply to you if:
The External HDD is:
SSD (solid stated drive, has no disk inside to spin up and suck current huge)

or some low power 2.5" HDD plugged into a full 500mA USB port.
or running any HDD 3.5" with a 2 amps power pack (or more) attached,
I see Seagate SSHD (highbrid( drives) still sucks 2.0amps motor startup currents. 3.5" and 2.5" at 1.0Amp startup.
Seagates current 3.5" "Desktop HDD series" (runs 2 to 2.5AMP startup in red below, on the  12vdc line.

The Enterprize driver look just like this at Seagate. The green line is 5vdc turning on . The red line is 12vd startup current on the  ST6000NM0235 drive.
Again these are scope views with current probe on the motor power wire.
idle current is about 0.5A(12vdc bus) after the startup ends.

Some laptops do not have a 12vdc pin on the eSATA port,  making the motor dead, on any connected HDD. (unless you connect a 12vdc power pack to the drive.)

Most 2.5" drives need no 12vdc at  all. (the motor is 5vdc only on most) not all.  The 5vdc bus then has the near same startup currents, of about 1.0Amps
eSATA to hot swap feature needs the following things to be set :
  • Mobo supports it.
  • Mobo BIOS this turned on.
  • The OS Windows? you use it must be enabled.

version 1.  8-8-2017  (rough draft, It is really just my journal , I share)