how plentiful ata drives can be put on a notebook and what are they used for?

how plentiful ata drives can be put on a notebook and what are they used for?

ATA is a type of computer nouns used to connect hard drives (aka IDE or P(arallel)ATA) and CD/DVD drives (aka ATAPI). It's a 40 or 80 pin connector. (40 is the elder, slower, 80 is the newerm faster. 80 pin connectors are also referred to as UtlraATA, or ATA/100, and several other names.)

Most newer computer are presently using SATA (Serial ATA) which is a different physical connection.

Each ATA port on a controller is typically competent to connect to 2 devices (a master and slave). The ribbon cable has three ends; one to connect to the controller (typically on the mother board), one to the Master drive and one to the Slave drive. Master and Slave is designated by a jumber on your device.
You can put 2 SATA drives. And they are used for indistinguishable purpose or regular IDE...Storage!!