 |
 |
|
|
|
The first thing to understand about mail is that, unless you're using a corporate server that automatically maintains copies of all transmitted messages, the data is actually stored on your PC. Most ISPs use POP (Post Office Protocol) servers that transmit received mail messages to your PC's local inbox; once delivered, the messages are deleted from the server. There are options that can be set (e.g. "leave mail on server") even after it's delivered, but eventually your disk quota will be exceeded and you'll stop receiving mail altogether. Once the mail messages have been delivered, no one else maintains copies. A disk failure or software defect could leave your mail file corrupted or even totally destroyed. In the case of a disk failure, only a few recovery options are available. If you've been taking regular backups, you can just revert to your most recent copy. Depending on timing, this might mean you lose nothing (if the backup is very recent) or a small percentage of your most recent messages. Alternately, you can take the disk to a data recovery service and hope they can reconstruct the required files; this is an expensive and often futile option. A corrupted mail file is another story. Generally, mail clients maintain messages using multiple folders; some are created by the software automatically (like "inbox" and "trash") while others ("notes from Mom") are user-created. In some cases, messages are stored in individual files, but other software packages use "mailbox" format files like those used on UNIX. These are usually flat ASCII files containing sequences of messages separated by message header data. Attachments are stored separately, often in an "attachments" directory, and are linked to the messages to which they were originally attached. Access to all the above is handled using index files or other schemes that keeps track of which messages live where. If the index is corrupted or destroyed, your mail client might have no idea where your mail is, even though the actual files still exist. Certain clients may be able to rebuild corrupted index files, while others may simply refuse to function properly. Happily, numerous mailbox repair/recovery tools are available from commercial vendors, such as PL File Recovery. In some cases the packages locate all available mail files and simply recreate new index files from scratch; others will actually rebuild whole servers if needed. Note that most products are specific to a given type of mail client or server - a product designed for Outlook may not work at all with Groupwise, and vice versa. Additionally, some companies (e.g. Ontrack) offer recovery services - you send them your files or give them access to the corrupted server, and they'll try to rebuild or recover index and other information. As a bonus, many such packages can also recover deleted messages, even if the email client's trash has been emptied. Most of us have had the experience of dragging the wrong folder to the trash, so this is an extremely useful feature. Note that such options may not work after a significant delay, since the files may have been overwritten or otherwise removed by the operating system. Obviously the best offense is a good defense (hint: take regular backups). It's good to know recovery services and repair packages are available for those worst case scenarios, though. |
|
