Before I get started on this week’s column, I want to introduce you to my new Backup Blog. Ever since I signed up for Google Alerts on the topic of “backup”, I’m overwhelmed with information, and the blog gives me a chance to post links to the most interesting bits in between reminders.
It also allows me to publish the back issues of this newsletter, so new subscribers can go back and read earlier articles. I’ll be putting the archives up an issue at a time over the next few days.
You can subscribe to the blog with your RSS newsreader (also known as an aggregator; I use the Sage plugin for Firefox), and get your backup news that way. (Never heard of RSS? Here’s an explanation.)
Everything in the newsletter will be republished in the blog, but not everything in the blog will be in the newsletter. So take a look and feel free to submit comments on any of the posts: https://www.fileslinger.com/blog.
And now for today’s feature: Backup Terminology. I try to avoid geek-speak, but there are some terms you’ll need to know in order to decide what backup solution is best for you. And because different people (and companies) use the same terms in different ways, it’s important for you to know how I’m using them in order to understand what I write.
I’ll start with the Slingerisms and then move on to other frequently-used backup terms.
FILE BACKUP means a copy of your files, either done manually through drag-and-drop or CD burning, or automated via a program like Karen’s Replicator. This is essentially what the Microsoft backup tool help file calls a copy backup—it’s a straightforward copy of individual files. I sometimes describe this as a data backup because what you’re copying is your data rather than your software or operating system. Depending on the number of files you’re copying, this kind of backup can be done onto almost any medium, including floppy diskettes and “key drives”.
DRIVE IMAGE means a copy of your entire hard drive, created with a program like Ghost or TrueImage, usually onto an external drive. This is the kind of backup that replicates your entire computer. Other terms for this are drive mirror and system backup or full backup. With a drive image your operating system and software are backed up along with your data.) Microsoft calls this a normal backup, and it’s what happens the first time you run their backup tool.
DIFFERENTIAL BACKUP means a backup that copies the files which have changed since the last backup was made. It’s not entirely clear just what distinguishes a differential backup from an INCREMENTAL BACKUP.
For Microsoft, the difference is whether files get marked as having been backed up. In other cases, incremental backups only copy the actual bits which are different—not whole files, but parts of files. The Geek Girls say that a differential backup copies the files which have changed since the last full backup and that an incremental backup copies the files which have changed since the last backup of any kind. (Are you confused yet? I am.)
Personally, I like the term “Differential Backup,” and that’s what I use to describe the way my own file backups work. Replicator compares the files on my computer to the files on my XHD. Any file which is newer on my computer is copied onto the XHD, overwriting the previous copy. Any file which hasn’t changed is skipped. This saves copying time, and that’s the whole point of doing anything less than a “full backup.”
I do differential file backups several times a day. That way, if I mess something up in between image backups, I still have a copy of it.
A few other terms you may encounter:
PROGRESSIVE BACKUP is a term which appears to have been coined by Dantz, makers of the popular Retrospect software, to refer to the fact that whenever you run their program, any new files are added into the backup.
ONLINE BACKUP can mean a backup which is kept connected to the computer you’re backing up, but it can also mean an INTERNET BACKUP—storing your backups on a website.
CUMULATIVE BACKUP refers to a procedure of adding on files each time you make a partial backup in between full backups. As HP explains it, “If you back up your system on a daily basis, the first cumulative tape will contain files updated in the preceding 24 hours, the second tape contains files updated in the preceding 48 hours, and so on.” This technique was developed for tape backups, which are something I’ll discuss in a future issue.
LIVE BACKUP is a term I found on a database backup site, and it refers to a continuous backup process, where backups are made as the files are changed. This is similar to what happens in a RAID system (discussed in an earlier newsletter). There are also software programs which monitor your files and back them up whenever they change. (Replicator can do that but I don’t have it set to run that way just at the moment.)
SELECTIVE BACKUP refers to a backup of certain files rather than of all your files. Most manual file backups are selective: you decide which files it’s important to back up.
I recommend making file backups on a frequent basis, particularly when it’s client files and business records you’re dealing with. I make a complete (drive image) backup once a week, after I send out this reminder.
If I’ve left anything out, please e-mail me or visit the Backup Blog and post a comment. (The blog site notifies me when new comments are posted.) I’ll put answers and additions on the blog site.
Meanwhile, go forth and back up!