OESF Portables Forum
Model Specific Forums => Gemini PDA => Gemini PDA - Hardware => Topic started by: geomannie on January 09, 2018, 09:40:12 am
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Hi,
I am not if this has been answered, but can anyone confirm the size of microSD that the Gemini will support?
Thanks
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Hi,
I am not if this has been answered, but can anyone confirm the size of microSD that the Gemini will support?
Thanks
Maximum 256GB, this has been confirmed by Planet. Actually, it is not known if this is because of a hardware limitation, a software only one (hence, this limitation will be removed with a later kernel), or if they are just claiming that the don't have tested SD cards with a bigger capacity, so they can't confirm if they are supported or not. It would be anyway interesting to try 512GB or bigger cards, too bad they are still very expensive (last time I checked they were sold for around 300 euros).
Varti
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Hi,
I am not if this has been answered, but can anyone confirm the size of microSD that the Gemini will support?
Thanks
Maximum 256GB, this has been confirmed by Planet. Actually, it is not known if this is because of a hardware limitation, a software only one (hence, this limitation will be removed with a later kernel), or if they are just claiming that the don't have tested SD cards with a bigger capacity, so they can't confirm if they are supported or not. It would be anyway interesting to try 512GB or bigger cards, too bad they are still very expensive (last time I checked they were sold for around 300 euros).
Varti
Thanks a bunch! However, I am now confused by microSD standards. I see that one can have SD, SDHC or SDXC. Any thoughts as to which the Gemini will support or which is best?
Cheers
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Maximum 256GB, this has been confirmed by Planet. Actually, it is not known if this is because of a hardware limitation, a software only one (hence, this limitation will be removed with a later kernel), or if they are just claiming that the don't have tested SD cards with a bigger capacity, so they can't confirm if they are supported or not. It would be anyway interesting to try 512GB or bigger cards, too bad they are still very expensive (last time I checked they were sold for around 300 euros).
Varti
Doing a little price comparison, the sweet spot for Micro-SD cards right now is 128GB, of which good ones can be had for ~$40. 256MB equivalents are three times as much. My thought is to use a 64GB one I already have until the price of the 256s comes down, but my needs for this device involve some but not vast amounts of data storage.
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Thanks a bunch! However, I am now confused by microSD standards. I see that one can have SD, SDHC or SDXC. Any thoughts as to which the Gemini will support or which is best?
Cheers
The long answer would entail a history of TransFlash, MMC, SD, SDHC, SDXC, UHS-I and UHS-II.
The short answer is: Anything labeled microSDHC or labeled microSDXC UHS-I should work fine.
Normal caveats for purchasing flash media apply - reputable brand from a reputable source. There are still a lot of fakes out there.
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Thanks. Reputable brand SDHC card now ordered in anticipation.
Cheers
Thanks a bunch! However, I am now confused by microSD standards. I see that one can have SD, SDHC or SDXC. Any thoughts as to which the Gemini will support or which is best?
Cheers
The long answer would entail a history of TransFlash, MMC, SD, SDHC, SDXC, UHS-I and UHS-II.
The short answer is: Anything labeled microSDHC or labeled microSDXC UHS-I should work fine.
Normal caveats for purchasing flash media apply - reputable brand from a reputable source. There are still a lot of fakes out there.
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AIUI, SDXC cards are identical to SDHC, only the cards come formatted as exFAT rather than FAT.
you can format FAT32 file systems a lot larger with linux than with Windows, the latter simply refuses!
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Thanks. Reputable brand SDHC card now ordered in anticipation.
Cheers
Thanks a bunch! However, I am now confused by microSD standards. I see that one can have SD, SDHC or SDXC. Any thoughts as to which the Gemini will support or which is best?
Cheers
The long answer would entail a history of TransFlash, MMC, SD, SDHC, SDXC, UHS-I and UHS-II.
The short answer is: Anything labeled microSDHC or labeled microSDXC UHS-I should work fine.
Normal caveats for purchasing flash media apply - reputable brand from a reputable source. There are still a lot of fakes out there.
I hope you mean microSDHC. An SDHC card isn't going to physically fit in the microSD slot.
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AIUI, SDXC cards are identical to SDHC, only the cards come formatted as exFAT rather than FAT.
you can format FAT32 file systems a lot larger with linux than with Windows, the latter simply refuses!
Has Linux found away to read exFAT natively? When I occasionally have had the need to read an exFAT card I've had to employ something called exfat-fuse, which was cooked up at, I think, Google. This is of some significance in that I'd kind of hoped to use the SDC as storage accessible to both Linux and Android sides, so it would pretty much need to be in a format both could read.
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Has Linux found away to read exFAT natively? When I occasionally have had the need to read an exFAT card I've had to employ something called exfat-fuse, which was cooked up at, I think, Google. This is of some significance in that I'd kind of hoped to use the SDC as storage accessible to both Linux and Android sides, so it would pretty much need to be in a format both could read.
I'm pretty certain exFAT is only usable as a FUSE file system, probably due to patent encumbrances.
I have a DSLR with a 64GB card and it has to be formatted exFAT for the camera to recognise it (can't even partition it down to 32GB and use FAT32), and I had to install FUSE utils and other things for it to be mountable on Linux.
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I'm pretty certain exFAT is only usable as a FUSE file system, probably due to patent encumbrances.
I have a DSLR with a 64GB card and it has to be formatted exFAT for the camera to recognise it (can't even partition it down to 32GB and use FAT32), and I had to install FUSE utils and other things for it to be mountable on Linux.
Me, too (re. DSLR with big card and what needs to be done to mount it). My concern now is what file system might be used for big MicroSD cards that would be happily recognized by both Linux and Android. Is there one?
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I'm pretty certain exFAT is only usable as a FUSE file system, probably due to patent encumbrances.
I have a DSLR with a 64GB card and it has to be formatted exFAT for the camera to recognise it (can't even partition it down to 32GB and use FAT32), and I had to install FUSE utils and other things for it to be mountable on Linux.
Me, too (re. DSLR with big card and what needs to be done to mount it). My concern now is what file system might be used for big MicroSD cards that would be happily recognized by both Linux and Android. Is there one?
We discussed this over on the Pyra boards and someone came up with a solid but in some ways ironic and sad solution.
Format the partition as NTFS and both Android and Linux as well as Windows should be able to read it native. Cameras are out of luck though. exFAT makes the cameras, Windows and Android happy but not Linux... BUT... On the Pandora (Pyra forums) a community member was able to incorporate the exFAT system in.
In theory, Android devices are native EXT4. I haven't tried that.
We're in for all sorts of entertainment with cards, card speeds, partitioning, formats, etc... It's going to be fun.
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the partition on my memory card containing a debian installation is formatted as ext4, I've not had any problems mounting it on various phones I've had since I set that up.
it's a shame that there's no F2FS driver for Windows: https://f2fs.wiki.kernel.org/development (https://f2fs.wiki.kernel.org/development)
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the partition on my memory card containing a debian installation is formatted as ext4, I've not had any problems mounting it on various phones I've had since I set that up.
it's a shame that there's no F2FS driver for Windows: https://f2fs.wiki.kernel.org/development (https://f2fs.wiki.kernel.org/development)
If Android can read and write ext4, then the world is a more beatuiful place than I awakened this morning thinking it was.
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the partition on my memory card containing a debian installation is formatted as ext4, I've not had any problems mounting it on various phones I've had since I set that up.
it's a shame that there's no F2FS driver for Windows: https://f2fs.wiki.kernel.org/development (https://f2fs.wiki.kernel.org/development)
If Android can read and write ext4, then the world is a more beatuiful place than I awakened this morning thinking it was.
I tried an EXT4 formatted microSDXC last night in a Galaxy Note 3, Android 5.1. It failed to recognize it.
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On the subject of filing systems, has anyone figured out what are the best ones for wear levelling?
For anyone who dosn't know what it is then have a read of Wear_leveling (https://en.wikipedia.org/wiki/Wear_leveling)
But basically our flash drives/cards are going to last for a much longer time if we have some part of the system doing that for us. It can happen in the flash controller hardware or in the drivers or in the filesystem. I'm hoping the internal drive is sorted by the controller/driver but have no evidence of this being the case, removable media on the other hand is unlikely to have this?
One additional thing to do is to set 'noatime' so that every read doesn't also cause a write: ReducingWrites (https://github.com/adamboardman/gemini-keyboard-apps/wiki/ReducingWrites)
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memory cards have an internal controller which does wear levelling, but I don't think they support TRIM?
on my DSLR, I occasionally (after copying off all the photos) do a secure erase on the card which esssentially factory resets the card so that the wear-levelling can work more effectively. You need the right kind of memory card reader and to use the official SD card formatter in the right mode for that: https://www.sdcard.org/downloads/formatter_4/ (https://www.sdcard.org/downloads/formatter_4/)
I don't know anything about the memory controller in the Gemini, whether it's simply flash connected directly to the CPU with the OS taking care of wear levelling, or if there's an intermediate controller. Hopefully the latter. If the former, you definitely want to be using F2FS with TRIM, and never put swap on the internal flash to avoid destroying part of it.
p.s. and a lot depends on whether its SLC flash or MLC etc, the former gives many more write/erase cycles.
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I'll be also using F2FS on my SD card with no swap partition, as suggested by speculatrix. I already use that filesystem on my Sharp Zaurus and I never had any problem with it.
By the way, does anybody know what type of internal storage will be used on the Gemini? Will it be an M.2 SSD drive (https://en.wikipedia.org/wiki/M.2 (https://en.wikipedia.org/wiki/M.2), and thus will it be possible to upgrade it?
Varti
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I thought most phone-like devices (and some budget convertible x86 tablets) used eMMC, but I could be mistaken. Since Planet seems to be trying to leverage some existing turnkey hardware to focus on the uniqueness of the form-factor, I would be (pleasantly) surprised if they were able to put a true SSD in the Gemini
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I'm pretty sure it will be eMMC. We have to hope they will have used an eMMC 5 module with high performance supporting HS400, to give good random I/O as well as sustained reads and writes.
I found this useful table:
https://www.datalight.com/solutions/technol...ison-by-version (https://www.datalight.com/solutions/technologies/emmc/emmc-feature-comparison-by-version)
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Gemini flash thoughts...
M.2? No.
Removable SSD? No.
Soldered on eMMC module? Definitely.
On partitions and formats...
For this I'm a bit torn.
Android since V6 has used EXT4 for it's own partition on the eMMC. But...
Depending on how the OEM (Planet Computers) sets up Android, it may or may not be willing to read any partition format other than Fat32 (cards <= 32GB) and ExFat (cards > 32GB).
There ARE Linux drivers for ExFat (Thank Google) utilizing FUSE. These can likely be made to work for Debian on the Gemini... maybe... They were able to make them work on the Pandora (Another ARM Linux computer).
I think Planet is planning to have us boot Linux from the microSD slot. Yet to be proven one way or the other. If this is the case, I'll probably put multiple partitions on my microSD card to use in the Gemini.
Something I'm still missing, and can't seem to find via searching... What is the definitive list of partition formats that Android 7 can support?
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File system support comes down to the configuration used when the kernel was built.
Planet should release the kernel sources under the GPL and so it should be possible to replace the kernel or add modules to it restrospectively. And this is where the shadow of Mediatek looms, since devices based on Mediatek rarely get the full kernel sources released, and may require closed source binary blobs which make it hard or impossible to upgrade to a newer kernel.
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One additional thing to do is to set 'noatime' so that every read doesn't also cause a write: ReducingWrites (https://github.com/adamboardman/gemini-keyboard-apps/wiki/ReducingWrites)
I just had a colorful hour or so, having applied the suggestions in this link and rebooting to a read-only filesystem such that I could not unedit /etc/fstab. Had to do a mount -o remount,rw /dev/sda2 / in order to be able to undo what I had done. Is this an ext4-only thing? Because in ext3 it makes for excitement but no joy. (Though I must confess that it reduced the number of writes to zero!)
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RE: noatime causing zero writes (readonly filesystem)
I've only ever used it with ext4, but from googleing the idea it appears other people have used it with ext3? Could you post your from/to lines in-case it was some other change? (I've also updated the page to avoid others having the same problem, I'll test it on my Gemini when I get it and update the page - or anyone else can)
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RE: noatime causing zero writes (readonly filesystem)
I've only ever used it with ext4, but from googleing the idea it appears other people have used it with ext3? Could you post your from/to lines in-case it was some other change? (I've also updated the page to avoid others having the same problem, I'll test it on my Gemini when I get it and update the page - or anyone else can)
UUID=00c71d45-5bc2-40a7-b52f-cd73c82d294f / ext3 errors=remount-ro 0 1
became:
UUID=00c71d45-5bc2-40a7-b52f-cd73c82d294f / ext3 errors=remount-ro,data=writeback,noatime,nodiratime 0 1
UUID=f33fcb46-c800-4a83-acef-3952e6f813d7 /home ext3 defaults 0 2
became:
UUID=f33fcb46-c800-4a83-acef-3952e6f813d7 /home ext3 defaults,data=writeback,noatime,nodiratime 0 2
Do you suppose it's the data=writeback setting that blows things up?
(I also have an additional drive in the machine, formatted ext4, but it is data only and has no UUID line at all, though this shouldn't figure in booting at all.)
The write reduction fix is of interest because Linux tends toward a lot of unnecessary disk activity, and reducing it is a Real Good Thing.
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It appears definitely to be a problem with the data=writeback. Just tried without it and all is tickety-boo.
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Excellent, I expect the access time bits have more of an impact than the writeback, so I'm glad they work for you.
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Excellent, I expect the access time bits have more of an impact than the writeback, so I'm glad they work for you.
There seems to be a noticeable performance increase as well. Thanks!
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I think Planet is planning to have us boot Linux from the microSD slot. Yet to be proven one way or the other. If this is the case, I'll probably put multiple partitions on my microSD card to use in the Gemini.
Not if this is accurate: (https://geminiplanet.com/2018/01/13/samsung-256gb-evo-plus-microsd-card/)
"Whichever model of Gemini PDA you choose, it already comes with a very healthy 64GB of on-board storage. Once you take into account the installed Android and Linux operating systems however, and then the space occupied by all your apps, and system and temporary files, that space will very quickly be significantly reduced. Many Gemini owners therefore will want to expand their storage with the addition of a MicroSD card."
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I think Planet is planning to have us boot Linux from the microSD slot. Yet to be proven one way or the other. If this is the case, I'll probably put multiple partitions on my microSD card to use in the Gemini.
Not if this is accurate: (https://geminiplanet.com/2018/01/13/samsung-256gb-evo-plus-microsd-card/)
"Whichever model of Gemini PDA you choose, it already comes with a very healthy 64GB of on-board storage. Once you take into account the installed Android and Linux operating systems however, and then the space occupied by all your apps, and system and temporary files, that space will very quickly be significantly reduced. Many Gemini owners therefore will want to expand their storage with the addition of a MicroSD card."
Considering the number of (likely unintentional) inaccuracies in those starter articles, it would not surprise me in the least if he's completely off in assumption land on those statements. No fault of his own, but the guy is a clearly writer trying to be a techie. I seriously doubt if he has anymore insights into the OS configurations on the Gemini than you or I do.
You will note through the articles that the author has never actually held a Gemini let alone looked at how the software is or isn't installed by default.