(feedback) microSD vs eMMC

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1

Hi, here is yet another feedback. It’s a bit long…

We need microSD in order to update OS, so what’s the point of eMMC?
I read somewhere that it’s more vibration resistent. But, DC power, USB,
ethernet connections are all more vibration sensitive than microSD.

If you get rid of eMMC, you would

  • save cost of eMMC
  • make room for regular HDMI port – it’s saving for us, because we wouldn’t
    need micro to regular HDMI cable.
  • make room for more USB ports – we wouldn’t need USB hub for keyboard,
    mouse, harddisk.

Another consequence would be for software developers. Currently, because
of 2GB eMMC, they are putting together barebone Linux distros. But, with
user supplied 8/16/32/64GB microSD, they would be able to offer a full Linux
distros which users are already familiar with. That means, no “busybox”,
no “dropbear”, no “shellinabox”, etc.

For an example, my current problem is with X Windows offered by Angstrom
(Ubuntu and Debian images don’t include X). With normal X Windows, you
would be able to log into BeagleBone Black from remote machine by simply
doing
X :1 -query ip.of.beaglebone.black
This would save me HDMI cables/converters which cost more than the board
itself. I read in this forum about using VNC. That’s unnecessary, though,
because remote X session is built into X Windows from the beginning.

2

So, if I get rid of eMMC and add the cost of USD, then that will save cost? Sorry, but that is not true. And it has nothing to do with “vibration”. It has to do with knowing what controller is in the eMMC vs. that uSD that you buy. Unless of course you are advocating that we ship board so that out of the box they do nothing, which is not something we choose to do.

And, for what it is worth, you actually do no need a uSD to flash the eMMC. There are several other ways of doing it (USB,Serial). It is just at this times those tools are not yet ready to support eMMC. Hoefully that will happen at some point.

Gerald

3

We need microSD in order to update OS, so what's the point of eMMC?
I read somewhere that it's more vibration resistent. But, DC power, USB,
ethernet connections are all more vibration sensitive than microSD.

SD cards also suck at wear leveling and most will fail long before a
similarly used eMMC due to the internal controller designs. Please do a
search on SD card failures on the list, you'll find many. I've not seen
any complaints of eMMC failures, yet.

If you get rid of eMMC, you would
    - save cost of eMMC
    - make room for regular HDMI port -- it's saving for us, because we
wouldn't
      need micro to regular HDMI cable.
    - make room for more USB ports -- we wouldn't need USB hub for
    keyboard,
      mouse, harddisk.

eMMC is cheap, cheaper than you can buy a similar sized SD card at
retail. It is also much easier to obtain decent eMMC in large-ish
quantity than SD cards.

Your comments about USB would require adding a USB hub, which adds cost,
similar to the cost of the eMMC. But you'd then also need another USB
connector. Connectors are very expensive.

Another consequence would be for software developers. Currently, because
of 2GB eMMC, they are putting together barebone Linux distros. But, with
user supplied 8/16/32/64GB microSD, they would be able to offer a full
Linux
distros which users are already familiar with. That means, no "busybox",
no "dropbear", no "shellinabox", etc.

I run Debian on my white bones. I partition my 4 GB SD cards to have a
2 GB partition of which about 200 MB is used. I'm running real Debian 6
armel. If you're having trouble making a sub-2GB Linux system, try
harder. It's quite easy, even including X.

For an example, my current problem is with X Windows offered by Angstrom
(Ubuntu and Debian images don't include X). With normal X Windows, you
would be able to log into BeagleBone Black from remote machine by simply
doing
    X :1 -query ip.of.beaglebone.black
This would save me HDMI cables/converters which cost more than the board
itself. I read in this forum about using VNC. That's unnecessary,
though,
because remote X session is built into X Windows from the beginning.

Both Debian and Ubuntu have X packages for ARM. I'm confused by your
insinuation that X doesn't exist on Ubuntu or Debian.

You can always order beagles from Circuit Co directly and ask for
modifications if you don't want certain things populated.

-Andrew

4

I doubt it. I've seen uSD sockets fail mechanically, and on investigating them
you can see how they are prone to that. I've never seen it on any of the other
connector types you mention.

Britton