wnd's weblog

Linux, SD card readers and HAL

4 Sep 2013 17:59:31 FFR, Linux

If your copy of GNU/Linux can’t find your SD card in a reader, try running lshal (which can be found in package hal in Debian) and then check again.

Earlier today I was trying to copy the stuff from an micro SD card, but failed miserably as the kernel log didn’t mention a thing about the card when it was inserted. Puzzeled, I inserted the card in my cheap Chinese Android tablet and behold, the stuff was there. I then tried the same card with a Linux laptop with no success. Baffled, I also tried other SD cards (regular and micro) with my desktop. None of the cards worked. The card reader appeared as /dev/sdg and that’s all there was for it. At the same time using an USB adapter for the micro SD card worked perfectly fine.

After asking the almighty Google about this, someone suggested running lshal as a mean to investigate remotely similar problem. After installing HAL, running it and grepping the output I saw the card was now available through /dev/sdg1. dmesg now also mentioned this “newly” attached device.

Obviouly I’ve fallen behind after introduction of DEVFS and udev, as I didn’t even think of HAL. In fact, I don’t even really know what HAL is. I’ve known what it stands for, I’ve known that for quite some time, but that’s about it. I still find it odd that dmesg didn’t list the device until hald was started (upon running lshal). Also, if HAL was so crucial part of the system nowadays, why is it marked as optional in Debian? My understanding here is rather limited, but why did things work so differently for “plain” USB sticks?

Oh well, immediate problem solved. Perhaps I educate myself about all this later.