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Re: Possibly erroneous "device not present" message during boot

On 04/15/2017 10:28 AM, David Wright wrote:
On Sat 15 Apr 2017 at 11:05:12 (+0200), Pascal Hambourg wrote:
Le 15/04/2017 à 02:37, David Wright a écrit :
Of course, an SD card can be
made to look like a USB stick just by sticking it in a card reader.
I guess you mean "in a USB-to-SD card adapter", which translates a
SD card into a USB mass storage device (/dev/sd*).
Yes, you guess correctly. Writing 40 years ago, I would use those same
words to describe a washing-machine sized object for reading punched
cards. Nowadays, if you type "card reader" into google, you will be
proffered several more sophisticated ones than mine, together with
some different varieties of credit card reader.

A SD card reader such as the one the OP has just exposes the SD card
as what it is, a SD/MMC card (/dev/mmcblk*).
I assumed that the OP, writing about a laptop, had no card reader,
and was inserting the SD card directly into the computer.

As it happens, if you do this with the ancient laptop I'm typing on,
it has the functionality of a card reader built into it and you get
a /dev/sd*, and that can be boot an SD card directly.


It turns out that there are two kinds of cards that look the same, but on a Dell laptop I have, one kind won't be recognized and the other works. I don't remember which is which, or what they are called. One is SD, the other something else. Of course, I found out the hard way, but it really doesn't matter, since I don't need to
use the laptop for that.