Please, iIn the future, when you have more than one unrelated questions,
it's best to ask them in separate messages.
a right arrow next to a program means what??
Beats me. Where are you seeing these arrows.
Also, why would we
defrag our computers?
Files are written in increments of disk space called "clusters." If you're
using NTFS with the default cluster size, your clusters are 4K each. Let's
say you write a few files, and they are in order like this:
file 1 cluster1
file 1 cluster 2 (end)
file 2 cluster 1
file 2 cluster 2
file 2 cluster 3 (end)
file 3 cluster 1 (end)
file 4 cluster 1 (end)
file 5 cluster 1
file 5 cluster 2
file 5 cluster 3 (end)
Now you delete files 2 and 4. Your disk now looks like this:
file 1 cluster1
file 1 cluster 2 (end)
available cluster
available cluster
file 3 cluster 1 (end)
available cluster
file 5 cluster 1
file 5 cluster 2
file 5 cluster 3 (end)
Then you write a new file which takes up five clusters. You disk now looks
like this:
file 1 cluster1
file 1 cluster 2
file 6 cluster 1
file 6 cluster 2
file 3 cluster 1 (end)
file 6 cluster 3
file 5 cluster 1
file 5 cluster 2
file 5 cluster 3 (end)
file 6 cluster 4
file 6 cluster 5 (end)
Note that file six's five clusters are not contiguous, but in three groups,
clusters 1 and 2, 3, and 4 and 5. That lack of continuity is called
"fragmentation," and makes it take longer to read or write the file, because
the drive heads have to move to get from cluster 2 to 3 and from 3 to 4.
Defragmentataion is the process is rearranging the clusters, so the files
are all contiguous again, something like this:
file 1 cluster1
file 1 cluster 2
file 6 cluster 1
file 6 cluster 2
file 6 cluster 3
file 6 cluster 4
file 6 cluster 5 (end)
file 3 cluster 1 (end)
file 5 cluster 1
file 5 cluster 2
file 5 cluster 3 (end)
That makes the files on the drive faster to read and write again.