I have tested the installation of openSUSE 13.1 in an external media, first I installed the OS in an USB Flash drive 2.0 connected to a USB 2.0 port, the installation was successful but it took almost 3 hours to complete the installation, once installed, I proceed to make some test, the system was running as expected to a good speed, but when I tested to install some packages, samba + base development pattern, It took 73 minutes to install.
The second test was made with an external hard drive 2.0 connected to the same port in the same computer with a laptop hard drive of 5200 rpm into the enclosure, this external drive has a power adapter, I made the same test as before, but the installation completed in 20 minutes and the installation of samba + base development pattern was complete in 6 minutes, my question is, Will an USB 3.0 flash drive work as fast as the external hard disk if connected to this USB 2.0 port?
I don’t know the answer. The speed probably depends on the particular flash drive.
The fact is, that write speeds to flash drives are a lot slower than write speeds to external hard drives. It’s the flash technology that is slow, rather than the interface speed.
I have an old, slow IDE drive in an external drive enclosure. Writing to it is a lot faster than writing to a new flash drive.
> minutes, my question is, Will an USB 3.0 flash drive work as fast as the
> external hard disk if connected to this USB 2.0 port?
An usb 3 device connected on a usb 2 port is pointless, it works at usb2
speeds, so you will gain nothing.
What you need to look at is the sustained data write speed of the flash
device. The technology allows for fast read and seek, but sustained
writing is slow (small or intermittent writes appear fast because of
caching). More expensive devices could be faster.
You will have to look at the specs.
–
Cheers / Saludos,
Carlos E. R.
(from 13.1 x86_64 “Bottle” at Telcontar)
On 2014-06-24 04:16, Fraser Bell wrote:
>
> nrickert;2650434 Wrote:
>> Yes. You are limited by flash speeds …
>
> … which are slower than external drives.
I’m a bit confused, though. It might be the late hours.
Internal SSD, are flash media, I understand. I know that they are very
fast on access speed, and read speed, but not so fast on sustained write
speed.
The “not so fast” is the doubt I have. Is it faster, on sustained write,
than usb sticks (should be!), than magnetic media (?), or is it just
slower than its own read speed, but faster (on sustained write) than
magnetic media?
Or is it even slower (on sustained write) than magnetic media?
:-?
Maybe it also depends in money spent. As always :-}
–
Cheers / Saludos,
Carlos E. R.
(from 13.1 x86_64 “Bottle” at Telcontar)
> I think you will find it is a different kind of flash media than USB.
Yes…
But how different?
Is it the same basic technology?
It occurs to me that it could be the same basic technology with the same
basic characteristics, but using tricks to speed it up. For instance,
they could be using a number of chips or sections in the chips, so that
write operations can happen simultaneously on several, and interleave
the resulting blocks. Or they could have a largish local cache: write
would be fast till it fills up.
Or they could be using a better flash technology. Much better? Just a
bit better?
:-??
–
Cheers / Saludos,
Carlos E. R.
(from 13.1 x86_64 “Bottle” at Telcontar)
Flash writes are totally different. You can not rewrite a location in flash you must ease it first then you can write and this is done in rather large blocks. Last I checked 100K blocks. So if you change one byte in a file 100K must be erased before a write can occur. Erases are rally slow. In USB sticks you got to erase before the write every time. In SSD there are write leveling algorithms that spread the writes so the old block is moved to a unused location to be erased at a convenient time and the write occurs in fresh flash RAM. So it is much faster then USB sticks and also will last longer since writes are spread across available memory rather then repeatedly to the same blocks. Since flash RAM as a limited write life this will let the SSD device live much longer then an USB stick used in the same way
