[ale] Linux alternative recommendation ?

[Ron Frazier]

<disclaimer ON>

I'll be glad to give you my opinion.  Opinions are plentiful and cheap.  
Your mileage may vary.

I am not a physicist, and am not an expert on flash memory technology.

<disclaimer OFF>

OK.  An SSD is a giant version of a memory stick, more or less.  The 
same pros and cons as mentioned before apply.  I cannot speak to the 
susceptibility to airport screening equipment as mentioned in my other 
post.  I love the idea of an SSD, although I don't currently own one.  
Properly configured and properly supported by the operating system, they 
are blazing fast.  One big current problem is cost, so you have to 
determine if it's worth $ 2 / GB to get one, as opposed to $ 0.10 / GB 
for HDD.  As someone else said, you probably won't get much speed 
advantage over an external HDD when connected to a USB v2 port.  
According to Wikipedia, USB v2 is capable of 480 Mbit/s (60 MB/s).  
That's the most you'll get out of any device connected to a USB v2 
port.  The SATA port on either a HDD or SSD is capable of about 6X that 
speed.  So, the bottleneck is going to be the USB port.  I don't know 
for certain, but I suspect that either the SSD or HDD will perform 
similarly when connected to a USB v2 port.  The HDD will be faster, and 
the SSD will be WAY faster, when connected to an internal SATA port on 
the PC.

I tried an experiment by copying 20 Ubuntu ISO files (about 13 GB) from 
one internal 7200 RPM SATA drive to another in my PC.  Data transfer 
speed varied widely, which may be due to the two platters not being 
synchronized.  In any case, the max consistent speed was about 50 MB / 
sec.  So, I don't know if a 7200 RPM drive can max out a USB v2 
connection, but it will come close.  A 10,000 RPM drive could probably 
exceed the limits of a USB v2 connection.  They are available in 2.5", 
but cost a bit more..  An SSD will almost certainly max out the USB v2 
connection.

So, the bottom line is this.  The SSD is probably better for your use as 
an external drive IF A) you want to pony up the money, and B) you 
convince yourself that airport scanners won't fry it.  It won't be much 
faster than a HDD if on USB, but it will be very durable and pretty much 
immune to mechanical shock (don't run over it with a big truck).  It 
will be mostly immune to electrical shock if properly enclosed (don't 
intentionally make sparks to it).  Get one with a 5 year + warranty.

If you're convinced that airport scanners will fry flash memory, go with 
a g-shock protected (as someone mentioned) NON HYBRID HDD with 7200 RPM 
speed.  If you want maximum possible speed, go with 10,000 RPM.  I 
didn't think about the airport thing when I originally mentioned the 
hybrid drive.  For that matter, I don't know how airport scanners effect 
HDD's either, but I presume, not so much.  The HDD will still be more 
susceptible to mechanical damage than an SSD, so g-shock feature 
notwithstanding, try not to smack the drive, especially while it's 
running.  Again, get one with a 5 year + warranty.

As I mentioned in another post, I have misgivings about the long term 
reliability of any flash memory device, including SSD's.  No matter what 
you choose, you need regular backups of critical data.  Perhaps even 
more so with a flash memory device.  Over the last few years, I've 
observed failures in several types of flash memory devices as follows:

a) when I was teaching, students reporting that their files vanished or 
were not accessible on memory sticks
b) my own relative's inability to access photos on a memory card, which 
I had to recover
c) a GPS device that suddenly decided it didn't want to run it's program 
properly, and didn't want to take a firmware update
d) routers that, periodically, start getting flaky, and have to have 
their firmware reloaded
e) some may call me crazy for mentioning this, but, severe solar storms 
are predicted in 2012 and beyond, which MAY be more likely to disrupt 
flash devices (I'm not an astronomer either.)

All these devices (a - d) are flash memory based.  And, I've seen them 
all flake out.  I wouldn't probably want to backup an SSD to an SSD.  
I'd back it up to an HDD, and possibly to online backup too.

So, there you have it, long answer to short question.  As with many 
things in technology, the answer is "it depends" on your use case.

Hope it helps.

Sincerely,

Ron



On 10/24/2011 3:14 PM, Courtney Thomas wrote:
> Ron,
>
> What is your take on SSDs vs HDDs ?
>
> Thanks again,
>
> C.Thomas
>
> On 10/24/2011 1:47 PM, Ron Frazier wrote:
>> There are a couple of benefits to "rolling your own" external drive.  
>> It is frequently the case that the prefab drive in a case type of 
>> packages don't have adequate cooling.  While the compact DIY 
>> enclosures for 2.5" drives usually don't have fans inside, good ones 
>> are made of aluminum, which has good heat dissipation.  Bigger 
>> enclosures sometimes have fans.  Western Digital had problems a few 
>> years ago with their packaged drive in a case (my book, passbook, 
>> whatever it's called).  The drives would fry themselves to death.  
>> Then you have to fret with RMAing the thing.  If you open the case, 
>> you void the warranty, and I don't think they had a 5 year warranty.  
>> If you choose carefully, you can get a bare HDD with a 5 year 
>> warranty.  Then you can switch it in and out of cases as you see 
>> fit.  You can also upgrade it to a larger drive if you choose, and 
>> not worry about voiding the warranty.
>>
>> Sincerely,
>>
>> Ron

<snip>

-- 

(PS - If you email me and don't get a quick response, you might want to
call on the phone.  I get about 300 emails per day from alternate energy
mailing lists and such.  I don't always see new messages very quickly.)

Ron Frazier

770-205-9422 (O)   Leave a message.
linuxdude AT c3energy.com

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