|OddMix COMPUTERS - DATA BACKUP|
Data Backup Choices Available Popular Personal Computer PC Users
Computer users should realize how very important is the backing up of computer data. This often mentioned data should not to be confused with other type of computer files. Data files are always user program generated files. This type of data is usually, scanned, dictated, recorded, received by e-mail or is the output of application programs. All files on the computer are not data files. Operating system files (Windows, Unix etc.), or application program files (Word, Paint etc.) are not data files. All of the operating system and application files can be easily reloaded when necessary from their own original distribution media, usually in the forms of floppies or CDs. Therefore those group of programs don't require daily backups.
|Picture 1. 8mm digital magnetic tape cassette|
Data backups made for long term storage usually referred to as archival. Most often the backup has to survive a much shorter time, until another more up-to-date version of it comes along. These more frequent backups are the casual or medium term backups. As computers came into existence, various storage media were investigated and used. Punched paper tapes, magnetic core, magnetic drum, magnetic domains, analog and digital tapes and disk, were made to use for data recordings. Lately optical and solid state (semiconductor) devices are also used. The average home computer user usually has three widely available choices for computer data backups.
1. Magnetic Storage is used extensively on most computers as the hard drives all use magnetic storage technology. Other currently used magnetic storage devices are the floppy and Zip-disc (as a kind of overgrown floppy), the various types of tape cassettes and cartridges shown on Picture 1. Magnetic recordings are the oldest, and sadly, still the most reliable type of backup methods currently available.
While floppy disks - Picture 2 - are phased out, as they are somewhat limited in their storage capacity, hard drives are getting larger and less expensive all the time. Disallowing driver electronics failure in hard drives; they make the most reliable long-term backups possible. To overcome prospective hard drive electronics failures, the use of multiple drive units are the most time and cost effective. This redundant device backup idea is based on the hope, that at least one of the multiple hard drives would survive to restart at another day.
|Picture 2. 3.5 inch 1.44 MByte floppy media|
2. Optical Storage Media types include CD (Compact Disk) and DVD type media, and some currently outdated types like worm drives. Most computers come equipped with at least CD or DVD readers, and many with read/write devices necessary to make these types of backups. Since diffusion has a lot to do with the longevity of these types of devices, the long-term storage prospect is not all that promising. Although most of us experienced how well old sound recordings survived on CDs, these disks were made using a different technology. And even with this more robust construction, sound recordings are always requiring built in error correction. Error detection and correction is acceptable for sound recording where a few bit in a wrong state does not even noticeable, but it is not permissible for a computer program.
3. Solid State Media Storage Devices are currently the most expensive backup devices available. They are definitely NOT suitable for archival storage! The memory devices used to store the data are extremely dependent on the ambient temperature of the device. Because of their small physical size and convenient USB connection, the use of these devices will continue to increase. Another little known problem with these devices is that they are only capable to function for a few thousand read-write cycles. This may sound like a large number, but any time a single, or a group of files are written to the memory-drive that is another cycle. Reading is not count for the life, only writing.