VXA Autoloader Technology                                                                                                         August, 2004 Page 4 of 8                                                                                              Introduction to Backup Automation The inadequacy of the manual backup process in an on-demand world of explosive data growth led to the introduction of the autoloader.  Autoloaders specifically address the human intervention challenge of successfully moving data to and from tape by automating the backup and retrieval processes. An autoloader is a compact storage device that contains a tape drive, tape cartridge slots, and a robotic mechanism that moves tapes between the slots and the tape drive.  Unlike libraries, which contain several tape drives and many cartridge storage locations, an autoloader typically contains only a single tape drive and up to ten cartridge slots.    Controlled by backup software, autoloaders enable specific backup routines to run automatically while simplifying data restoration.  The autoloader’s robotic mechanism operates as a random-access “changer” device with software that controls libraries, or as a sequential-access “stacker” device with tape drive control software. The random-access feature distinguishes the autoloader from a simple stacker device, which only processes cartridges in sequential order. With ten cartridge slots, a single tape loading operation, occurring weekly or even bi-weekly, addresses as many as ten backup events.  By reducing the frequency of human involvement from daily to weekly, the autoloader eliminates the opportunity for human error or neglect by 80%.  Filling the autoloader with a new batch of tapes at extended intervals is intrinsically more reliable than depending on daily tape swapping, and even accounts for employee absence and turnover. Conveniently, a weekly tape loading routine also organizes the tape sets for off-site rotation.  A single new tape loading session produces a collection of the most recent backup copies prepared for transport to a disaster-proof location.  Furthermore, handling tapes as complete sets greatly reduces the probability of tape misfiling errors. The autoloader also simplifies the majority of restoration operations caused by the loss or deletion of recent files.   Because the initial full backup and several daily incremental or full backups remain in the autoloader after their completion, in most cases the tape containing the file to be restored is still loaded and available online.  Furthermore, when the restore is completed, the backups will continue on schedule without operator intervention. Invariably, tapes rapidly deteriorate with frequent human handling due to greater exposure to contamination and mishandling.  In contrast, autoloaders, based on tests performing Figure 2 – Illustration of two sets of tape movements over a two-week backup cycle. p1   p2   p3   p4   p5   p6   p7   p8