Generally, drives with jumpers for manual, slave, and cable select settings refer to IDE drives, aka parallel ATA. Drives have these jumpers because IDE controllers have two channels, one for master and one for slave, which means for one IDE cable you will have connectors for two drives. Usually if you have two devices on an IDE controller you want to set the jumper on your primary device as a master, and the second one as a slave. So if you have a drive you want to normally appear as C:, you would set this drive as master, and the other device residing on the IDE cable as a slave. You can also set both drives to "Cable Select" which will automatically assign a master and slave drive (most often the device at the end of the cable will be set to master). I prefer to have my master and slave devices set manually, however.
Serial ATA (SATA) drives do not utilize master/slave settings as there is only one cable per device.