i was kind of experimenting, i burned iso file using cdrecord command, my medium was a cd-rw and it has already a data written on it...i was not able to delete that current data stored in the medium, i just burned the iso file right away...now, i cannot view my cd-rw, the files inside...what do you think happened to the medium? was it destroyed???lol...pls help me...im kinda paranoid with these things...what do you think should i in order to prevent this to happen again...thanks...

in addition, when i mount the cd-rw, it says "mount: not a directory"...and when tried openning it to windows, it says "please insert cd"...wtf do think happened???i was not able to place the -dummy option...T_T..or the media was destroyed because i was not able to delete the existing data...

When a CDRW has been burned/written to and finalized, it technically becomes a CD. No longer a RW.
In order to use it again, it needs to be blanked first. You can do this with cdrecord, and, if you like, you can blank and burn in one command. To blank, do like this:
That will blank a CDRW and make it ready for use.
to burn and blank at the same time, use something like:
and to simply burn, use:
Note: I use the dev=/dev/hdd instead of the SCSI way of 0,0,0. This works only with a 2.6 kernel as far as I know.
Note 2: I'm not sure if the 'speed' argument affects the 'blank speed', so I prefer to blank and burn in separate steps, though I have had success both ways.
Note 3: You need to use the PAD option if you want the disk to work properly, especially if it will be used on a CD drive other than the one it was made on.

When you mount it, the filetype will be iso9660 or UDF, depending on exactly what you put on the disk. But still, it has to be burned properly before it will work

thanks dude, what will i do with the cd-rw??could i still recover it??uhmmm...it seems i can't erase it since it cannot be detected...currently, im trying to save it using nero...hope it will work...thanks again

If the CD was made under windows initially, OR it was a multisession CD which wasn't finalized, you may need the cdrwtool package, for UDF packetwriting support.
As for recovering the data, if you wrote over preexisting data, the chances are small to none.
If you have tried mounting it as UDF, iso9660, AND tried mounting it as a UDF-packet-written multisession data disk, and it's all no-go, I would consider forgetting about the data, and just blanking the disk and starting fresh.
Maybe you could use some recovery tool to rescue some stuff, but.... I don't know how it would go.