What is the main disadvantage of using Programmed I$/$O$?$

The user is unable to give input until the CPU is ready.

It is inefficient and wasteful of CPU cycles

The user has to write code for operations involving I$/$O$.$

Programming using the CPU is very slow.What are the disadvantages of the cycle stealing approach in DMA?

Storing the value in the PC to enable I$/$O involves multiple registers write operations.

Cycle Stealing involves delaying the internal clock to do longer tasks.

DMA controller steals a bus cycle to transfer data, causing CPU operation to slow down.

Cycle stealing can cause the DMA controller to temporarily shut down.