Using two SD cards and when to safely remove them?


RobeeJay

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Mar 7, 2012
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Two SD card questions, hopefully someone can help me with answers...

Firstly, what's the best way to use two SD cards? It seems games create save data on the one in slot 1, and obviously I can't really mount the second one in the same place at the same time. Is there any clever trick to using two cards for apps? Or should I just move things like Scummvm games and roms that the relevant apps allow you to put anywhere on the second card?

And secondly, when is it safe to remove an SD card? Is it like windows, do I have to eject it first to ensure it's been written to? I'm sure I read a message somewhere about not removing them when the system is in standby, but I haven't seen that in ages so I'm beginning to think I'd imagined it. :/

TIA for any replies.
 
Games save to the SD card they themselves are launched from.

There should be some safe remove button to click somewhere like on windows, but don't know right now where it is. Either at the right in the panel at the bottom of the screen or in the file manager on the left side, or both.
 
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Be sure that the cards have a label - otherwise, the card you inserted first will be mounted as mmcblk0p1, regardless if it's the left or right slot. This can cause issues with some programs.


If you label the card, it will always be mounted with it's name (just be sure that you don't have two cards with the same label ;) )
 
Games save to the SD card they themselves are launched from.
That is very handy to know, thanks! I should be able to just move them around on the Pandy itself, ta.
To elaborate, applications live on the pandora/ directory in your SD card. On my case:
$ ls /media/PANCARDA/pandora/
README.txt appdata apps desktop menu
I've labeled my first slot card as PANDCARDA.
The PND files are either on the desktop or menu directories:

$ ls -1 /media/PANCARDA/pandora/menu/
CodecPack.pnd
NESemu.pnd
PanPlayer.pnd
drastic.pnd
...snip...
 And the save data somewhere in appdata directory. For example for DraStic emulator:

Code:
$ ls /media/PANCARDA/pandora/appdata/DraStic/           
backup  config  drastic_file_info.txt  input_record  profiles  roms  savestates  system  unzip_cache
You can move the PND file and corresponding directory under appdata to a different card and you should have all your saves and such working right away.
 
And to make something more clear ( :p at Yoyobuae :-D ):

$ ls /media/PANCARDA/pandora/
README.txt appdata apps desktop menu
I've labeled my first slot card as PANDCARDA.
Be sure that the cards have a label - otherwise, the card you inserted first will be mounted as mmcblk0p1, regardless if it's the left or right slot. This can cause issues with some programs.

If you label the card, it will always be mounted with it's name (just be sure that you don't have two cards with the same label ;) )
Labelling and slots work like this:

If your card has no label, it gets a name like mmcblk<x>p<y>. The x is just the lowest one which is still free at the time you insert the SD card (so usually it's 0 for the first and 1 for the second and nothing else). The y is the number of each partition on your SD card (if you don't know what partitions are, y is just always 1).

So that naming scheme has nothing to do with left/right slot. The system doesn't care about which slot a card is in. For most parts, it doesn't even know.

You can give your cards custom labels with a programs such as gparted (gparted is on the repo). When you do that the cards will appear under that name on all computers (including Pandora) you put them in.

They still get a name {1} like described above (at least on the Pandora, on other Linuxes maybe with a different naming scheme, but similar), but it's hidden from sight unless you go poke around the inside of the system (which you need to do for certain a little more advanced things).

{1}(do they? they should, but I never consciously checked)
 
{1}(do they? they should, but I never consciously checked)
Yes:


$ ls /dev/ | grep mmc
mmcblk0
mmcblk0p1
mmcblk1
mmcblk1p1

The labeling affects the name of the directory where they are mounted.
 
Before removing a card you ought to right click on its icon either on the desktop or in Thunar and select 'unmount/eject', but that often fails on the Pandora due to a small bug in the PND system somewhere, so I tend to treat it like an old 8-bit system - wait until the light stops flashing, then you're safe to eject.
 
^ Don't let those SD cards be the boss of you, rip those suckers out when you feel like it.
 
^ Don't let those SD cards be the boss of you, rip those suckers out when you feel like it.
:)Probably he should, but only if he has backups and is willing to write them back now and again (which is obviously annoying).
 
And secondly, when is it safe to remove an SD card? Is it like windows, do I have to eject it first to ensure it's been written to? I'm sure I read a message somewhere about not removing them when the system is in standby, but I haven't seen that in ages so I'm beginning to think I'd imagined it. :/
The behaviour is a little different than on windows, as the system is configured with small write caches in mind, while on Windows (or more generally speaking on most desktop operating systems) write caches are usually rather big. Thats why there is an eject functionality in the first place > if you use it, the system gets the signal that all I/O operations that may be still cached currently are to be completed immmediately.So while only a "sync" through a terminal will give you absolute certainty, a rule of thumb that never let me down in about three years of daily Pandora usage: after the SD LED stopped blinking just count to five before mechanically ejecting the card.
 
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