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dvd_drive_status [2014/03/13 17:56] – beandogdvd_drive_status [2021/10/17 23:50] (current) – beandog
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 ====== dvd_drive_status ====== ====== dvd_drive_status ======
  
-  * [[https://github.com/beandog/dvd_info|dvd_info at github]]+  * [[dvd_info]] - main package 
 +  * [[https://github.com/torvalds/linux/blob/master/include/uapi/linux/cdrom.h|Linux cdrom.h]] 
 +  * [[https://github.com/beandog/dvd_info/blob/master/dvd_drive_status.c|dvd_drive_status.c]]
  
-  * [[https://raw2.github.com/beandog/dvd_info/master/dvd_drive_status.c|dvd_drive_status.c]]+This program is a successor to the small program [[trayopen]] (which also inspired this one). ''trayopen'' works great, but it doesn't poll two things: if the drive is busy or if it has media. ''dvd_drive_status'' adds that feature plus a few more.
  
-This program is a successor to the small program [[trayopen]] (which also inspired this one).  ''trayopen'' works great, but it doesn't poll two things: if the drive is busy or if it has media.  ''dvd_drive_status'' adds that feature plus a few more.+It has support on and off for *BSD systems. I like to work on it, and then I don't. The kernels are different, and have different tray status checks and so on. I'm limited by that.
  
-To build, just download the [[https://raw2.github.com/beandog/dvd_info/master/dvd_drive_status.c|dvd_drive_status.c file]] and compile it. +A man page is included with the ''dvd_info'' program (man dvd_drive_status).
- +
-<code> +
-$ wget https://raw2.github.com/beandog/dvd_info/master/dvd_drive_status.c +
-$ gcc -o dvd_drive_status dvd_drive_status.c +
-</code>+
  
 === Context === === Context ===
  
-The reason this program was written, was because I was having problems having programs access the DVD drive before it is ready.  Duplication is simple.+The reason this program was written, was because I was having problems having programs access the DVD drive before it is ready. Duplication is simple.
  
   * Open your DVD tray   * Open your DVD tray
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   * get frustrated and have to re-run your program once the drive is ready   * get frustrated and have to re-run your program once the drive is ready
  
-The problem here is that the OS will close the tray, and pass off control of the device back to the user, while the device is still in a non-ready status.  So, using the above example, even closing it with ''eject'', it will still complain, because eject finishes before the drive is ready:+The problem here is that the OS will close the tray, and pass off control of the device back to the user, while the device is still in a non-ready status. So, using the above example, even closing it with ''eject'', it will still complain, because eject finishes before the drive is ready:
  
 <code> <code>
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 </code> </code>
  
-To fix this, we need to properly check if a drive is ready to be accessed or not.  Just being "closed" doesn't mean it is.  I wanted to solve that problem, so this is what I came up with.+To fix this, we need to properly check if a drive is ready to be accessed or not. Just being "closed" doesn't mean it is. I wanted to solve that problem, so this is what I came up with.
  
 === Drive and Tray States === === Drive and Tray States ===
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 In every state, the DVD drive is ready to send commands to it, and not have your program puke, **except** for if it is opening or closing. In every state, the DVD drive is ready to send commands to it, and not have your program puke, **except** for if it is opening or closing.
  
-I should clarify.  When I say "opening or closing" I don't mean just the physical state of the tray, this also includes the time that either the OS or the drive has to poll the tray and see what's going on.  If your drive has an LED on front, you'll see it lighting up after you close the tray.+I should clarify. When I say "opening or closing" I don't mean just the physical state of the tray, this also includes the time that either the OS or the drive has to poll the tray and see what's going on.  If your drive has an LED on front, you'll see it lighting up after you close the tray.
  
 It's that state where the drive is //not ready// to be accessed.  And when the drive's not ready to access, then automated programs will complain because it thinks there's not a DVD in the drive -- even if there is.  Basically, you can't effectively know if something is in a proper state. It's that state where the drive is //not ready// to be accessed.  And when the drive's not ready to access, then automated programs will complain because it thinks there's not a DVD in the drive -- even if there is.  Basically, you can't effectively know if something is in a proper state.
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 === Checking Drive / Tray Status === === Checking Drive / Tray Status ===
  
-Anyway, inspired by [[trayopen]] and having a desire to learn C myself, I came up with this little program, ''dvd_drive_status''.  And by little, I mean that.  ALL it does is just query the state of the DVD drive using the Linux cdrom.h.+Anyway, inspired by [[trayopen]] and having a desire to learn C myself, I came up with this little program, ''dvd_drive_status''. And by little, I mean that. ALL it does is just query the state of the DVD drive using the Linux cdrom.h.
  
-A nice bonus from the CD driver is that it lets you see if there is media in the tray or not, while the tray is closed.  So again, this is very helpful for scripts that want to automate querying the status of your DVD drive.+A nice bonus from the CD driver is that it lets you see if there is media in the tray or not, while the tray is closed. So again, this is very helpful for scripts that want to automate querying the status of your DVD drive.
  
 === Scripting === === Scripting ===

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