Start-up offers unique way to back up, share and remotely access data Dropping prices for hardware and hard disk drives mean new products to accommodate our growing collection of digital photos, music and other data.\u00a0Two weeks ago\u00a0we looked at the Tritton ASAP, which adds network-attached storage functions to a broadband router. This week, we look at Mirra Personal Server, essentially a back-up device that lets you access files remotely from a Web browser and share access with people you authorize.Mirra automatically backs up in real time every file added or changed in the client PC folders you configure for backup, keeping eight previous versions. Although called a "personal" server, Mirra attaches to the network. When you add Mirra client software to multiple PCs, the system backs them all up automatically. The product also makes the Mirra files available remotely, for free. Log in at\u00a0Mirra.com, and the company acts as a go-between, displaying (but not storing) the files on your Mirra for download. Need a file from work while at home? Forget your PowerPoint presentation when you travel? Mirra will fetch the files using an Secure Sockets Layer-encrypted connection. Handy. Mirra also lets you send e-mail notices to others granting them continuing access to any or all the folders on your Mirra. To gain access, they log on at the Mirra site, type in their e-mail address and a password you assign. The company touts this as a great way to share digital images with family members, and the feature works well. But your sales manager can also put new price sheets in a particular folder and grant salespeople or customers access.As a backup-only option, Mirra offers great value compared to tape backup products. The Mirra 80G-byte version costs $399; the 120G-byte version I tested costs $499. Plus, unlike tape, the Mirra backup routines work automatically. Every time you add, change or delete a file, the Mirra server reflects the change, but holds the deleted files for easy restoration until you delete them. Since the most common use of data backup is to restore accidentally deleted files, this is a great feature. But \u2014 and it\u2019s a big but \u2014 Mirra lacks any way to store files offsite.To be a great product for small businesses \u2014 and a complete back-up solution \u2014 Mirra needs to include an FTP client like\u00a0RocketVault\u00a0and\u00a0Toshiba Magnia\u00a0have, so you can ship files offsite to your Web host, for instance. However, the debut version is still an excellent choice for consumers.Also note, because Mirra\u2019s software relies on Microsoft .Net infrastructure, it only supports Windows XP and 2000 operating systems. Mirra's software relies on Microsoft's .Net infrastructure and makes so many changes to the PCs\u2019 Registry files, I doubt it can support Macintosh anytime soon.