4 ms·

Android phones don't do this anymore, for the technical reason that allowing a computer to mount a filesystem directly requires that the phone unmount it. Mass

by dTal 8y ago

Android phones don't do this anymore, for the technical reason that allowing a computer to mount a filesystem directly requires that the phone unmount it. Mass storage expects a block device, so there's no wrapper that one could provide that would make this work with the native filesystems of the phone. What could be done is to dedicate a file on the phone as block storage, and expose that as a mass storage device. This would suffer from the same problem (of the phone not being able to access it at the same time), but if it's dedicated "flash drive emulation" space then perhaps this behavior won't be as surprising to the user.

gdulli 8y ago
> allowing a computer to mount a filesystem directly requires that the phone unmount it I don't think that's true. My S8 storage is mounted and accessible from my computer right now while at the same time playing music from the same storage. I can still take pictures/write to the storage.
- dTal 8y ago
  As mass storage, or MTP? The distinction is why I qualified with "mount a filesystem directly". MTP doesn't do that.
  - TulliusCicero 8y ago
    You said "Android phones don't do that anymore", "that" referring to "have it show up as a removable storage device". Pointing out that the protocol used is leaky or bad in some technical way doesn't change that Android phones do in fact show up as removable storage devices when connected to (at least Windows) PC's. Your original assertion was incorrect. samcday even said they just wanted to copy some files around. You don't need to be able to modify files in-place from the PC to accomplish this.
    - ernesth 8y ago
      UMS (USB Mass Storage) is a protocol. MTP is a different protocol. Android devices don't support UMS anymore.
TulliusCicero 8y ago
> Android phones don't do this anymore They don't? Since when? I still have a Pixel 1 but it's running Android P, so the latest major version of Android, and this still works fine.
- deleted 8y ago
  [deleted]
skykooler 8y ago
Android phones show up as MTP devices, which are basically file-level storage instead of block-level storage. Most OS's (besides MacOS) will display this with the same interface as a USB mass storage device.
- dTal 8y ago
  MTP is a horrible protocol which renders the abstraction very leaky in my experience, to the extent that it's inaccurate to refer to it as "removable storage" and expect to behave in similarly sane fashion to a proper flash drive. For example, there's no support for modifying a file in-place - the entire file must be read out, modified, and then written back. These kinds of restrictions render it slow and unreliable. Wikipedia tells the sordid story: https://en.wikipedia.org/wiki/Media_Transfer_Protocol#Comparison_with_USB_Mass_Storage https://en.wikipedia.org/wiki/Media_Transfer_Protocol#Compar...
  - TulliusCicero 8y ago
    > MTP is a horrible protocol which renders the abstraction very leaky in my experience Nevertheless, it's still removable storage that can take the place of the most common use case of portable flash drives: moving files around from one computer to another. Which is explicitly what we were originally talking about. Pointing out that it doesn't work for some other use case that you yourself brought up doesn't make any sense. That's not what everyone else was talking about.
    - dTal 8y ago
      I'm not going to debate you in three places at once, that's just obnoxious and clutters the thread. Ultimately this is an argument about the precise semantics of "removable storage". I don't regard an MTP device as "removable storage" - it's another computer that one speaks to using a special protocol, with severe limitations. So is an iPhone - with special, protocol-speaking software, you can certainly put arbitrary files on it. I interpreted the parent to mean that they wanted to plug the phone in to "any PC" and have it Just Work. MTP isn't so great at that, especially from my perspective as a Linux user, where MTP support is no more built-in than iOS-protocol support. From this standpoint, "removable storage" == "USB mass storage". On the other hand, it sounds like whatever Apple provides is much worse even than MTP, and less well supported in general.

by dTal 8y ago

gdulli 8y ago

> allowing a computer to mount a filesystem directly requires that the phone unmount it I don't think that's true. My S8 storage is mounted and accessible from my computer right now while at the same time playing music from the same storage. I can still take pictures/write to the storage.

dTal 8y ago
As mass storage, or MTP? The distinction is why I qualified with "mount a filesystem directly". MTP doesn't do that.
- TulliusCicero 8y ago
  You said "Android phones don't do that anymore", "that" referring to "have it show up as a removable storage device". Pointing out that the protocol used is leaky or bad in some technical way doesn't change that Android phones do in fact show up as removable storage devices when connected to (at least Windows) PC's. Your original assertion was incorrect. samcday even said they just wanted to copy some files around. You don't need to be able to modify files in-place from the PC to accomplish this.
  - ernesth 8y ago
    UMS (USB Mass Storage) is a protocol. MTP is a different protocol. Android devices don't support UMS anymore.

TulliusCicero 8y ago

> Android phones don't do this anymore They don't? Since when? I still have a Pixel 1 but it's running Android P, so the latest major version of Android, and this still works fine.

deleted 8y ago
[deleted]

skykooler 8y ago

Android phones show up as MTP devices, which are basically file-level storage instead of block-level storage. Most OS's (besides MacOS) will display this with the same interface as a USB mass storage device.

dTal 8y ago
MTP is a horrible protocol which renders the abstraction very leaky in my experience, to the extent that it's inaccurate to refer to it as "removable storage" and expect to behave in similarly sane fashion to a proper flash drive. For example, there's no support for modifying a file in-place - the entire file must be read out, modified, and then written back. These kinds of restrictions render it slow and unreliable. Wikipedia tells the sordid story: https://en.wikipedia.org/wiki/Media_Transfer_Protocol#Comparison_with_USB_Mass_Storage https://en.wikipedia.org/wiki/Media_Transfer_Protocol#Compar...
- TulliusCicero 8y ago
  > MTP is a horrible protocol which renders the abstraction very leaky in my experience Nevertheless, it's still removable storage that can take the place of the most common use case of portable flash drives: moving files around from one computer to another. Which is explicitly what we were originally talking about. Pointing out that it doesn't work for some other use case that you yourself brought up doesn't make any sense. That's not what everyone else was talking about.
  - dTal 8y ago
    I'm not going to debate you in three places at once, that's just obnoxious and clutters the thread. Ultimately this is an argument about the precise semantics of "removable storage". I don't regard an MTP device as "removable storage" - it's another computer that one speaks to using a special protocol, with severe limitations. So is an iPhone - with special, protocol-speaking software, you can certainly put arbitrary files on it. I interpreted the parent to mean that they wanted to plug the phone in to "any PC" and have it Just Work. MTP isn't so great at that, especially from my perspective as a Linux user, where MTP support is no more built-in than iOS-protocol support. From this standpoint, "removable storage" == "USB mass storage". On the other hand, it sounds like whatever Apple provides is much worse even than MTP, and less well supported in general.