
Wrong, the CD300 (external) is just a plain ol' SCSI device.


No, multisession capability and double speed are two different thing.  Its just  
that the newer CD ROM drives have both capability.  Multisession means that  
when you put more pictures on a photo CD after the first session, the drive can  
read and display them.  Double speeds just transfer ANY type of data (excluding  
sound) at around double the speed.

 
CD150 is not multisession capable.  This means that you lose the ability to add  
any more pictures after the first time (must buy a new CD).  Finally, since the  
CD150 is not a double speed drive, it will require twice as long to transfer  
data (excluding sound).