AutoDoubler compresses only disks that are checked in the AutoDoubler control panel. By default, only the startup disk is compressed automatically. If you turn off AutoDoubler on all disks, no automatic compression will occur, but files already compressed stay compressed and work normally.
For example, in the picture below, the disks "Boot", "Maxima", "Apps & Utils" and "Develop Misc" are all set to be compressed automatically, but the disk "Compile" will not be compressed automatically:
To check or uncheck a volume, place the cursor over the "-" or "√" and click. Checking a volume indicates it will be compressed automatically and unchecking it indicates it will not be compressed automatically.
NOTE: checking or unchecking a volume only controls automatic compression. Compressed files and applications will work normally and operate correctly whether or not the volume is checked.
When Compression Begins
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AutoDoubler compresses automatically in the background after the Macintosh has been idle for a while. "Idle" means the mouse hasn't moved, no clicks or keystrokes have occurred, and the serial (modem/printer) ports are not being used. You can change the amount of time AutoDoubler waits in the "General" dialog:
In addition, AutoDoubler has a schedule for compressing, so it doesn't needlessly scan and rescan your disks. Generally, AutoDoubler will start scanning your disk within 2 minutes after booting up your Mac. If you interrupt AutoDoubler's scan, it will try again when the machine is idle, picking up again where it left off. If it finishes a scan, then it does the next disk. If it finishes all disks, it schedules another scan for a future time.
How AutoDoubler Shows Its Activities
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When AutoDoubler is scanning, it shows one of two cursors, the AD "S" cursor or the AD "C" cursor:
The "S" cursor means "Scanning" and the "C" cursor means "Compressing". Scanning means that AutoDoubler is looking for files to compress. Compressing means that AutoDoubler is actually compressing a file.
NOTE: for technical reasons, the "S" or "C" cursor may be drawn in the menu bar instead of changing the cursor itself.
NOTE: the "..." cursor is never used while compressing in the background; it is only shown when other programs request that AutoDoubler decompress a file.
Interrupting AutoDoubler
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To interrupt AutoDoubler, simply move or click the mouse, or type any key. AutoDoubler should stop its activities within a few seconds. In very rare cases, it may take as long as 20 or 30 seconds to interrupt AutoDoubler.
NOTE: if the AD "..." cursor is showing, you cannot interrupt AutoDoubler because it is responding to a request to open the file. Interrupting the process would cause the program opening the file to not work properly.
Which Files Does AutoDoubler Compress?
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AutoDoubler compresses only eligible files and applications. Some types of files are never eligible for compression. These include:
• files in any System Folder and its subfolders
• locked files or files that are in use
• certain special types of files, such as virtual memory files
• files that AutoDoubler can't make any smaller, such as files compressed by other programs, or files that are very small.
• files on disks that have automatic compression turned off
Other files may or may not be eligible according to other factors:
• files that you specifically exclude using the AutoDoubler "Don't Compress" command
• files that are not yet old enough. (You can specify how "old" is old enough using the "Settings" button for each volume.)
The "Free Space" Goal
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The settings ("Settings") for each volume contain a free space goal. This goal is expressed as a percentage of free space of the entire disk size. For example, a free space goal of 25% on a 100 megabyte disk would instruct AutoDoubler to try to keep at least 25 megabytes of free space at all times.
To keep the maximum amount of free space, set the free space goal to 99% (the default). If you set a lower free space goal, AutoDoubler will stop compressing files when it has met the goal. For example, if you set a free space goal of 25% on a 100 megabyte disk, AutoDoubler will stop compressing (or never start perhaps) as soon as there is 25 megabytes of free space on the disk.
A: Open the AutoDoubler control panel and check your settings to see if the volumes you want compressed are checked. Then, check to see if the free space goal may already be met. Set it to 99%. Then, set the "wait" time to 1 minute. Finally, restart your Macintosh. AutoDoubler should start scanning or compressing within 2 minutes.
AutoDoubler's Safety Features
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AutoDoubler incorporates several safety features designed to protect your data from inadvertant damage due to disk error or other system malfunction. By default verification is on for every volume (you can change this in the "Settings" dialog). While verifying slows down background compression somewhat, we strongly recommend that most people leave it turned on. (With verification turned off, AutoDoubler still does a quick read-after-write verify to detect disk errors). With verification on, AutoDoubler compresses files as follows:
1. The original file is opened read-only and AutoDoubler compresses into a temp file.
2. The compressed (temp) file is decompressed into RAM and verified against the original file.
3. The files are swapped.
4. AutoDoubler verifies the temp file again by checksumming it.
5. AutoDoubler deletes the original file
If, in step #2, the verify process fails (i.e the decompressed file does not match the original), AutoDoubler presents an alert similar to the following:
This error usually occurs because of a disk error, or some kind of system problem. In any case, it means that the compressed file is not the same as the original--so AutoDoubler leaves the original alone. Because AutoDoubler cannot determine what caused the error, AutoDoubler also turns off automatic compression on the volume in question.
If this error appears, it's a good idea to use Disk First Aid to check your disk (it's supplied with Apple's System Software). Also, use the DiskTester program to test your disk (it's one of the utilities supplied with AutoDoubler). If either of these programs finds a problem with the disk, it's a good idea to make a backup of any important files, then try to correct the problem. If no problem is found, go ahead and re-enable automatic compression for the disk.
If the problem occurs again and again, please call us, as this should not happen. (But please test your disk first as mentioned above). BEFORE calling us, please write down the EXACT error message you receive. In particular, write down the code number (e.g Code 29).
If it's a particular file that AutoDoubler has a problem with, try duplicating it, then trashing the original to see if that makes a difference. If not, please send us the file on a floppy disk and we'll see what we can find out.
How AutoDoubler works with DiskDoubler
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DiskDoubler is AutoDoubler's companion product. It offers a number of compression features not found in AutoDoubler, including self-expanding files, split files, combine files, high speed file copying and the ability to backup files to another disk in compressed form.
AutoDoubler works by itself, so you do not necessarily need DiskDoubler. However, if you have both, they complement each other nicely. In fact, when AutoDoubler compresses files, it creates standard DiskDoubler files which are compressed using AutoDoubler compression. If you ever turn off AutoDoubler, files simply show up as DiskDoubler application files and work normally with DiskDoubler. In this way, you always have access to your files even if you turn off AutoDoubler, because they are stored as normal files.
DiskDoubler offers two additional compression methods not found in AutoDoubler (Method A and B). While these compression methods may compress smaller than AutoDoubler can, they are considerably slower when accessing files. You might want to use them if you are sending files via modem, where minimum file size is important.
DiskDoubler comes in an expand-only version. There are two names for this application: “DDExpand” and “AD Expand Util”. They are both the same program and both can expand files compressed by either AutoDoubler or DiskDoubler. If you have DiskDoubler you do not need this program, because DiskDoubler itself can expand the files. If you have AutoDoubler only, then “AD Expand Util” can be used at any time to expand compressed files.
