DVD type: DVD-R or DVD+R

​I have a Dell Dimension 2350 and am trying to work out which type of DVD to buy.​

​I have two CD drives. My D drive is what I have used for reading CDs, my E drive for writing to. {I don't know whether both can be used for reading and writing, but think that only my E drive can be used for writing}.​

​They are:​

​HL-DT-ST CD-RW GCE-8481B [CD-ROM drive] - D​
​LITEON DVD-ROM LTD163 [CD-ROM drive] -E​

​Through a google search, I have found that the Liteon is a DVD-R compatible drive, so intend to purchase some DVD-R discs and give them a try. The only reference I have found to the HL-DT-ST makes me think this is a DVD+R device. I am confused, partly because the description of the HL-DT-ST includes "CD-RW" which implies to me that it too can write to discs.​

​ ​

​Any help appreciated.​

​ ​

​ ​