Difference between Controller & Host Controller

[rahulkhajuria]

Question 1 ) What is the Difference between a Controller , Adapter & Host Controller ?

Question 2) Also what is a Standard OpenHCD USB Host Controller ?

Question 3) I just learned that the SMART attributes of the Hard Disk are stored in the IDE Controller . I fail to understand how the attributes can be stored there when the controller is nothing but an Integrated Circuit or bunch of Integrated Circuits . Please Explain .

 

[rcgldr]

Question 1 ) What is the Difference between a Controller , Adapter & Host Controller?

An adapter converts one type of interface to another, such as PCI Express bus to SCSI, or pehaps ethernet to SCSI. A controller is just a component in a device that controls some aspect of the device. The component that deals with an interface, such as IDE or SATA is an example of a controller. A host controller is a controller in the "host" system, as opposed to a "device" controller which is in the device, such as a hard drive.

Question 2) Also what is a Standard OpenHCD USB Host Controller ?

Just a generic controller. Microsoft reference:
http://msdn.microsoft.com/en-us/library/aa940140(WinEmbedded.5).aspx

Question 3) I just learned that the SMART attributes of the Hard Disk are stored in the IDE Controller.

The information is not stored in the IDE specific part of the controller. On some PC's, and/or RAID adapter controllers, the smart attribute history is stored in some type of non-volatile ram. The information is mostly used to warn the user that hard drive should be replaced.