Re: System on a chip - performance relative size and setup (how can the (Debian) setup make a difference?)
<intentionally top posting, as I didn't see a good place to make this comment
within the previous text>
About the only thing I'd add to what others have said is that they now make
SSDs in a different form factor -- if you look for them, they start with an M,
iirc -- they are in the same size range as an SD card (well, a regular one,
not a micro).
You need a special socket to plug them into, and I'm not sure which (if any)
single board computers (I'm trying to use that to refer to computers using a
system on a chip) have that kind of socket.
<nothing added below here>
On Tuesday, June 18, 2019 09:14:19 AM Andy Smith wrote:
> Hi Erik,
>
> On Tue, Jun 18, 2019 at 02:26:57PM +0200, Erik Josefsson wrote:
> > As far as I understand, it is quite recent that SD cards are fast and
> > large enough to be able to carry and run an entire Debian instance.
>
> Not really recent. I've run Debian sarge on a 128MiB CompactFlash
> card and I'm sure people have done more extreme things than that.
>
> > If this is the case, maybe there is only theory available regarding
> > whether you can make a computer "run faster" on a 64GB SD card than on a
> > 32GB SD card when cards are otherwise identical.
>
> So firstly, SD cards in the general case aren't that performant or
> reliable. You can spend more money to get faster and more durable
> ones. The unique selling point of SD cards is the form factor –
> they're small and have no moving parts. They're meant to go in
> devices like cameras, dashcams, cell phones, etc.
>
> Given two SD cards that differ only in capacity, I would not expect
> their performance to differ. The bigger one may last longer (survive
> more writes) due to you using less of its capacity.
>
> > I don't really know how swap works on a standard computer, even less how
> > it works when the whole computer runs from/on a SD card.
>
> It doesn't work any differently, except that swapping onto SD
> generally isn't great because they aren't that fast and they often
> have fairly low write endurance.
>
> SD cards aren't like SSDs, even though they are both made from a
> form of flash memory. Modern SSDs and flash drives have much better
> write endurance than modern SD cards.
>
> > Swap is supposed to be make your computer pretend that you have more RAM
> > than it actually has, but if the whole computer is running from/on RAM
> > (or is it?), then what does swap mean?
>
> I don't know why you have introduced the concept of a computer
> running from memory, as that is a completely different topic. A
> computer running from SD card isn't much different to a computer
> running from an HDD or an SSD. It's just a block device.
>
> Now, due to the low write endurance of your typical SD card, some
> people — especially those making small single-purpose devices — do
> configure things to load off of the SD card into memory and then run
> largely from memory. This prevents writes into the SD card, thus
> prolonging its life. But that tactic is not in any way required when
> using SD cards and can be done with any block device.
>
> > On Teres-I with redpill RC2 (now there is a RC3 that I have not yet
> > installed) an unfortunate website with pop up commercials (like dn.se)
> > can eat all performance there is and freeze the mouse for hours. I would
> > guess that could have been fixed on a normal computer with "more RAM",
> > i.e., "more swap"? But is the same true for e.g. Teres-I?
>
> Sorry I am unfamiliar with Teres and redpill.
>
> > Second question is if it is meaningful to buy a "super duper blazing
> > fast" SD card for the task to run a whole Debian system?
>
> If you wish to run a general purpose operating system off of an SD
> card then yes I would suggest that the fastest and more durable one
> you can afford would be a good idea. But also consider a regular
> SSD as some of the low capacity ones may compare favourably in
> price with a specialist SD card.
>
> > There is a very expensive 64GB SD card from SanDisk that is called
> > Extreme Pro that costs twice as much as same size Extreme Plus. Specs
> > say it is "super duper blazing fast" for video in "Ultra HD 4K", but
> > would Pro also be faster than Plus for the task of running Thunderbird
> > and Firefox at the same time?
>
> Running big apps like that will benefit more from having enough
> memory. After that is satisfied, fast storage will certainly help.
> You'll have to look at the exact specifications of Plus vs Pro.
>
> What are you trying to achieve?
>
> Cheers,
> Andy
Reply to: