# Function Calls

I/O operations use the following calls. See Kernel Folio Calls, in the 3DO System Programmer's Reference for complete details on these calls.

## Opening and Closing Devices

The following calls open and close devices:

- `CloseNamedDevice()` Closes a device previously opened with `OpenNamedDevice()`.
- `FindDevice()` Returns the item number of a device.
- `FindAndOpenDevice()` Finds and opens a device item.
- `OpenNamedDevice()` Opens a named device.

## Creating, Deleting, and Creating Pointers for IOReqs

The following calls handle IO requests:``

- `CreateIOReq()` Creates an I/O request.
- `DeleteIOReq()` Deletes an I/O request.
- `LookupItem()` Gets a pointer to an item.

## Controlling the I/O Process

The following calls handle I/O processes:

- `AbortIO()` Aborts an I/O operation.
- `CheckIO()` Checks if an asynchronous I/O request has completed.
- `DoIO()` Performs synchronous I/O.
- `SendIO()` Requests asynchronous I/O.
- `WaitIO()` Waits for an asynchronous I/O request to complete.