Alsoft DiskWarrior - 4.0 지침 매뉴얼
Graphing a Disk Directory
Chapter 2: Using DiskWarrior
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Graphing a Disk Directory
DiskWarrior allows you to create a graph that indicates the degree the directory is internally
fragmented. This graph visually shows you the number of fragments and the distance each
fragment is out of place. Rebuilding your directory with DiskWarrior optimizes your directory.
Other programs don't provide the true directory optimization provided by DiskWarrior.
fragmented. This graph visually shows you the number of fragments and the distance each
fragment is out of place. Rebuilding your directory with DiskWarrior optimizes your directory.
Other programs don't provide the true directory optimization provided by DiskWarrior.
Background
To understand directory optimization you first have to understand the way that the directory is
internally organized. If you don't want to read the details it is enough to know that the data
structures in the directory can be internally fragmented and use space inefficiently. Directory
optimization is the process of organizing the data structures for fastest access. Directory
optimization typically results in a 50% to 60% decrease in the time it takes programs to scan the
directory and a 10% to 20% decrease in startup time. If you want the details then read on.
internally organized. If you don't want to read the details it is enough to know that the data
structures in the directory can be internally fragmented and use space inefficiently. Directory
optimization is the process of organizing the data structures for fastest access. Directory
optimization typically results in a 50% to 60% decrease in the time it takes programs to scan the
directory and a 10% to 20% decrease in startup time. If you want the details then read on.
Mac OS Standard (HFS) and Mac OS Extended (HFS Plus) disk directories have a very complex
structure. Each file or folder (item) on a disk has an entry in the disk's directory. These entries
are in order of enclosing folder and then item name. This is similar to a yellow pages directory
being sorted by type of business and then business name. Just like a yellow pages directory, the
disk directory has pages—except that its pages are called nodes. Unlike the yellow pages, nodes
are dynamic and change as you add and delete items. It's sort of like a real-time yellow pages.
structure. Each file or folder (item) on a disk has an entry in the disk's directory. These entries
are in order of enclosing folder and then item name. This is similar to a yellow pages directory
being sorted by type of business and then business name. Just like a yellow pages directory, the
disk directory has pages—except that its pages are called nodes. Unlike the yellow pages, nodes
are dynamic and change as you add and delete items. It's sort of like a real-time yellow pages.
Imagine that the pages of the yellow pages are not in order and at the bottom of each page it says
"Continued on page n," where ‘n’ is the page that contains the next set of listings for the particular
type of business that you're looking up. Well, nodes are not necessarily arranged in order and
each node has a reference, or link, to the next node that contains the next set of ordered items.
"Continued on page n," where ‘n’ is the page that contains the next set of listings for the particular
type of business that you're looking up. Well, nodes are not necessarily arranged in order and
each node has a reference, or link, to the next node that contains the next set of ordered items.
When you have a fresh new directory, all of the nodes are in order. So node 1 has a link to node
2 which has a link to node 3, and so on. Nodes don't stay in order for very long. Whenever a file
or folder (item) is created, an entry for the item is added to the directory in the appropriate
node. When a node fills up, a new node is added and the entries are divided evenly between the
old node and the new node. This leaves both nodes only half full. The new node is most likely
going to be at the end of the directory, just like an addendum. To keep the items in the nodes in
order, node 1—which was previously linked to the old node—will link to the new node and the
new node will link to the old node.
2 which has a link to node 3, and so on. Nodes don't stay in order for very long. Whenever a file
or folder (item) is created, an entry for the item is added to the directory in the appropriate
node. When a node fills up, a new node is added and the entries are divided evenly between the
old node and the new node. This leaves both nodes only half full. The new node is most likely
going to be at the end of the directory, just like an addendum. To keep the items in the nodes in
order, node 1—which was previously linked to the old node—will link to the new node and the
new node will link to the old node.
For example, let's say that you have a directory with 3 nodes. Node 1 links to node 2 which links
to node 3 (Figure 2-4). If you add an item that causes node 2 to overflow, a new node 4 will be
added. The items from node 2 and the new item will be split between node 2 and node 4. Node
to node 3 (Figure 2-4). If you add an item that causes node 2 to overflow, a new node 4 will be
added. The items from node 2 and the new item will be split between node 2 and node 4. Node