On 6/23/19 8:40 AM, Jonas Smedegaard wrote:
Is it meaningful to test the SD cards with an USB-adapter? (the MicroSD
slot would be occupied by the SD card the machine is running from/on)
Testing SD cards on a different controller may help understand
_potential_ features of cards, but not_actual_ reachable potentials.
If you prefer an analogy: Reading in a magazine that some Formel-1
driver can cut a corner while driving 60km/h in same model car as yours
does not mean that you can expect to cut that same corner at that speed:
Depends not only on the vehicle (disk device) but also on the driver!
Sure. I have tried to drive the 4 cards along exactly the same path
(i.e. flashbench) to reduce my influence on the performance.
Unfortunately I cannot tell which one is the best from the resulting data.
If the fio benchmark can tell me which card is the best, I will try it
at some point.
Of those figures, I consider the random ones more important in most
configurations. i.e. if I had to choose between a device that
supported a bit higher sequential read/write but much lower random
read/write, I'd rather have the random read/write, because that
tends to have more impact on interactive usage than sequential.
Yes, going back and forth between Thunderbird and Firefox while
copying text snippets from one app to the other sometimes ends in a
mouse pointer freeze.
That's basically what I do most of the time...
Biggest speed gain (on a limited computer like Teres-I) is likely had
with changing to less ressource hungry tools.
Instead of Firefox try GNOME Web (apt install epiphany-browser). It
uses the rendering engine "Webkit" so is likely to handle most websites.
For an radically lighter browser rendering fewer real-world websites
properly and with an arguably less friendly user interface, try Surf.
This is very helpful. I have installed epiphany now. Thanks!
A lighter alternative with ok UI and somewhat decent rendering engine is
Netsurf, but unfortunately that one won't make it into Debian Buster.
Instead of Thunderbird try Balsa or Claws Mail.
OK. Thanks!
SD cards tend to have poor random IO speed so I would never use one
for general purpose computing if I could use an HDD or SSD instead.
If random IO speed most likely is the real bottle neck, do you know of
any particular brand/label/kind/category of MicroSD card that is
significantly better than others in that regard?
https://github.com/ThomasKaiser/Knowledge/blob/master/articles/A1_and_A2_rated_SD_cards.md
(this is perhaps 5th time I share that link with you; 2nd on this list)
The article by Thomas Kaiser ends with an open discussion that you can
probably just as well buy A1 cards made before 2017. The last card I
bought is neither A1 or A2 but marked with a XC II logo. That particular
markup is not mentioned in Kaiser's article.
So the article cannot tell me which of my 4 cards is likely to be the
best for my usecase:
MicroSD SanDisk Extreme PRO 64GB [3] XC II
MicroSD SanDisk Extreme PLUS 64GB [3] XC I V30 A2
MicroSD SanDisk Extreme PLUS 32GB [3] HC I V30 A1
MicroSD SanDisk Ultra 32GB [1] HC I (10) A1
Not sure if chasing some microseconds of better performance will make
a difference, but if it is anything like parking with a heavy truck
with heavy trailer in a small parking lot with other cars, then I
guess a microsecond extra is just as important as an extra centimeter
:-)
To give you some idea of what decent SSDs manage:
http://strugglers.net/~andy/blog/2019/05/29/linux-raid-10-may-not-always-be-the-best-performer-but-i-dont-know-why/
I don't think I can make Teres-I boot from an external SSD.
Through the USB2 interface you can. Won't reach the full potentials of
SSD (see Formel-1 analogy above) but may still beat SD-cards.
You cannot_boot_ via USB2 interface but you can store your data there
which helps some scenarios (e.g. possibly helps Firefox hanging, as that
might be due to its working on cache data below your $HOME.
Ahh.. there's another hint! For some applications, disk partition matters?
I hope there is no downside to having two browsers installed, as long as
you don't use them at the same time!
Best regards.
//Erik
