TAILIEUCHUNG - Chapter-14-Tapes backups and floppy disks

In Chapter 11 we looked at hard disks. In this chapter, we’ll consider how to guard against data loss, and how to transfer data from one location to another. These are functions that UNIX traditionally performs with tapes, and we’ll look at them in the next sections. Because FreeBSD runs on PCs, however, you can’t completely escape floppy disks, though it would be an excellent idea. We’ll look at floppies on page 256. | 2 April 2003 17 00 47 The Complete FreeBSD page 251 In this chapter Backing up your data Using floppy disks under FreeBSD 14 Tapes backups and floppy disks In Chapter 11 we looked at hard disks. In this chapter we ll consider how to guard against data loss and how to transfer data from one location to another. These are functions that UNIX traditionally performs with tapes and we ll look at them in the next sections. Because FreeBSD runs on PCs however you can t completely escape floppy disks though it would be an excellent idea. We ll look at floppies on page 256. Backing up your data No matter how reliable your system you are never completely protected against loss of data. The most common reasons are hardware failure and human error. By comparison it s very seldom that a software error causes data loss but this too can happen. UNIX talks about archives which are copies of disk data in a form suitable for writing on a serial medium such as tape. You can however write them to disk files as well and that s what people do when they want to move a source tree from one system to another. You ll also hear the term tarball for an archive made by the tar program which we discuss below. v 2003 04 02 06 47 36 251 2 April 2003 17 00 47 The Complete FreeBSD . tools page 252 Backing up your data 252 What backup medium Traditionally PCs use floppy disks as a removable storage medium. We ll look at floppies below but you can sum the section up in one statement don t use floppy disks. Floppy disks are particularly unsuited as a backup medium for modern computers. Consider even a minimal system with a 2 GB hard disk. Storing 2 GB of data on floppies requires about 1 500 floppies which at each would cost you 450. Copying the data to a floppy takes about 50 seconds per floppy so the raw backup time would be about 21 hours plus the time it takes you to change the floppies which could easily take another three or more hours. During this time you .

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