There are several factors at play here:
* CD's are slower than hard drives
* Once the CD is inserted, it has a spin-up time (where many drives cannot start reading the CD until the drive is spinning at full speed)
* Once your OS can start reading from the CD, the OS has to "mount" the disc to the rest of the OS's drive structure. The basic structure of the disc is read into memory so that subsequent accesses are faster.
All of this takes times and this is a major simplification of what happens. Your hard drive is "mounted" as the OS is started so you do not see any of these delays.
The reason you notice these pauses is because any action that shows a drive listing (such as opening My Computer or an other Windows explorer window with drive letters showing) has to wait for the CD to be fully mounted prior to accessing it. You can blame these pauses mostly on the fact that most of Window's UI code is not multi-thread safe, and so updates to the display must wait for the background operations, like CD mounting, before explorer displays its results. Microsoft could have rewritten the way explorer works and have it display everything except for the hot swappable devices first and then go back and fill in those details as it found them. That, apparently, is more work than Microsoft was willing to do.
* CD's are slower than hard drives
* Once the CD is inserted, it has a spin-up time (where many drives cannot start reading the CD until the drive is spinning at full speed)
* Once your OS can start reading from the CD, the OS has to "mount" the disc to the rest of the OS's drive structure. The basic structure of the disc is read into memory so that subsequent accesses are faster.
All of this takes times and this is a major simplification of what happens. Your hard drive is "mounted" as the OS is started so you do not see any of these delays.
The reason you notice these pauses is because any action that shows a drive listing (such as opening My Computer or an other Windows explorer window with drive letters showing) has to wait for the CD to be fully mounted prior to accessing it. You can blame these pauses mostly on the fact that most of Window's UI code is not multi-thread safe, and so updates to the display must wait for the background operations, like CD mounting, before explorer displays its results. Microsoft could have rewritten the way explorer works and have it display everything except for the hot swappable devices first and then go back and fill in those details as it found them. That, apparently, is more work than Microsoft was willing to do.
