unmounting removable disk took a long times

[Nils Kassube]

Anom wrote:
> When I unmount any removable media like flash disk, MMC, etc. It took
> a long time. sometime it itook more than a minute or two to unmount
> the drive.
>
> This is usually happen after I copy file to/from the drive. But if I
> didn't do anything or if I give sometime after copying to/from the
> drive before unmounting it, the problem doesn't occur.

When you copy data to a medium, it is not written immediately, but is 
first kept in memory. It is written do the medium when there is no memory 
left or after a short delay (30s?). This behaviour is used to speed up 
the writing of data, if there are many small files.

If you unmount the medium, the data are immediately written from memory to 
the medium. Depending on the write speed of the medium and the cached 
data, that can take a long time. If you have a USB stick with an 
indicator LED, you can watch this behaviour. However, there should not be 
a delay if you only copied files FROM the medium.


Nils