On 8/12/07, <b class="gmail_sendername">David Hazel</b> <<a href="mailto:david.hazel@enchaine.com">david.hazel@enchaine.com</a>> wrote:<div><span class="gmail_quote"></span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div>
<div><span><font color="#0000ff" face="Arial" size="2">OK, so
far I haven't had a reply that really answers my original questions, so let me
rephrase them:</font></span></div></div></blockquote><div><br>I'd tend to disagree, but let's go on ;-) <br></div><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div><div><span><font color="#0000ff" face="Arial" size="2">1.
Given a full directory path, how can I determine FROM WITHIN AN APPLICATION
which storage device (memory card) this corresponds with? In other words,
starting with something of the form "/dir1/dir2/dir3/file", how can I identify
the storage device that this resides on?</font></span></div></div></blockquote><div><br>Well, that one would best be determined by reading the output of df or mount I would think. Because the Linux file system is so flexible, there may not be an actual "device" associated with a given path. Some of the paths in the file system are actually output from running applications. Others might be mounted across the network using any number of network file systems. For instance, the /proc directory doesn't really exist on a Linux hard drive so much as is output by a program running on the machine. So when you say you want to "find which storage device a path corresponds with" there may not be an answer because the question is wrong. Read on for more info...
<br></div><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div><div><span><font color="#0000ff" face="Arial" size="2">2.
Having found the above, how can I then find that storage device's serial number?
(Again, FROM WITHIN AN APPLICATION)</font></span></div></div></blockquote><div><br>Um, actually that was the answer everyone provided. No need to yell - that's generally what gets most Linux advocates bristling and starts flame wars.
<br><br>Just read the text file at the specified location. Where we said "cat XXXXXX", cat was just meaning dump the contents of that file to the console, so you could just open that file like any text file and read the serial number out of it. That's Linux 101, but certainly is alien to anyone who has done Palm, PocketPC or Windows development.
<br><br>So in Python for instance, you might do:<br><br>mypath = '/sys/devices/platform/mmci-omap.1/mmc1*/cid'<br>srcfile = open(mypath,'r')<br>myserial = srcfile.readline()<br>srcfile.close()<br># tada! no need for any include's either. Nice and simple.
<br><br>You can use the same method to find the type of processor in the device, how much memory card space is in use, and untold many other tidbits of cool information. Keep in mind, Linux aka Unix was originally designed around everything communicating to each other through what is basically console I/O. It's a really neat system when you think about it. This means there's no special API that needs written or header files that must be available for each language in order to access this information. Other aspects of the Linux OS are actually changed just simply by writing to these fake "text files" in your directory structure. These fake "text files" are just the communications medium between applications. And that's a Fact. ;-)
<br></div><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div><div><span><font color="#0000ff" face="Arial" size="2">Fact:
I can programmatically determine an SD card's serial number on a Windows Mobile
device. Therefore I expect this to be possible on the Nokia 800 as
well.</font></span></div></div></blockquote><div><br>Sure, just read it from the file system as described above. Linux provides the /sys/devices (or on a desktop normally /proc/whatever) "file system" to make it easier to do this, so there's not even an API you need. Just read the settings you're looking for from the OS supplied text file.
<br></div><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div><div><span><font color="#0000ff" face="Arial" size="2">Fact:
I can programmatically map a directory path onto its corresponding device under
Mac OS X (which is BSD Unix with go-faster stripes). Therefore I expect to be
able to do something similar on an N800 running a variant of Linux (which is
Unix-like, right?).</font></span></div>
<div><span><font color="#0000ff" face="Arial" size="2"></font></span> <br></div></div></blockquote></div><br>If you're talking about "mounting" sure, but you'll need to do it as root for security reasons. If that's not what you mean, you'll need to clarify.
<br><br>Someone who's a C programmer might be able to expound on my comments and give other options as well.<br><br>Also, on a side note, you sent your response directly to me and not the list, so I'm submitting it back to the list as well assuming it was an oversight on your part.
<br>