RTG News: March 1996TAPE DRIVE CAPACITYIf you back up your hard disk at all, you probably use a tape drive. Recently, several manufacturers have offered "800 megabyte" tape drives at less than $200. The HP Colorado T1000 and the Conner TapeStor 800 are representative models. Unfortunately, these drives are not a good match to today's typical hard disks, which may store 1.2 gigabytes (more than 1200 MB). The drives use a Travan TR-1 tape, which holds 400 MB of uncompressed data. The manufacturers assume that software compression increases the capacity by a factor of two, hence the 800 MB claim. In actual use you will not get a factor of two with the data on real hard disks. To be safe, assume a compression ratio of 1.5 to 1, or 600 MB on one tape. Unless your hard disk is partitioned into separate drives of 600 MB or less each, you will need to use multiple tapes to do a complete backup. This is very inconvenient, because you must be present to switch tapes. If the entire disk could be backed up onto one tape, you could set the software to do the backup at night. Another problem is speed. The ads claim a speed of 9.5 MB per minute. Even if that speed were accurate, a 1275 MB drive would require more than 134 minutes for a complete backup, not counting the time it takes to change tapes. To verify that the backup was successful, the software must compare the data on the tape to the data on the hard disk. That takes just as long as writing the data to the tape in the first place. So the total time is at least 4.5 hours and, of course, you must be there to change the tapes. Solution: either buy a tape drive with greater capacity, or partition your hard disk into tape-size chunks (600 MB). If the backup is done at night, unattended, then the speed is not important. Please note that file servers on networks must be backed up also, but the considerations are somewhat different. Unattended backup is still crucial, but speed may also be important for large disk drives. WINDOWS 95 CRASHESWe have used Windows 95 for a while and found it to be a significant improvement over previous versions of Windows. Occasionally a program would "perform an illegal operation" and Windows would shut it down; this just means that the application has a bug and Windows prevented it from causing damage to the operating system or to other applications. Even WordPerfect 6.1 for Windows has worked reliably after we applied the "Perfect Office update" (which Novell made available on their Internet site). Recently, after we started using TurboTax, Intuit's tax preparation software, Windows 95 became unstable. Sometimes the screen display would disappear completely. At other times, programs that had been reliable would crash. This experience demonstrates the fact that Windows 95 is not completely protected from bugs in applications, especially Windows 3.1-compatible (16-bit) applications. Perhaps we will see greater reliability as software developers create more Windows 95-only (32-bit) applications. THE VOICE-ACTIVATED TYPEWRITER: COMING SOON?
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