In: Accounting
Explain the GFS backup technique. Is it used for sequential files or direct access techniques? Explain.
The GFS backup technique, which is used for sequential master files, begins when the current master file (the father) is processed against the transaction file to produce a new updated master file (the son). Note that the son is a physically different file from the father. With the next batch of transactions, the son becomes the current master file (the new father), and the original father becomes the backup file (grandfather). This procedure is continued with each new batch of transactions, creating several generations of backup files. When the desired number of backup copies is reached, the oldest backup file is erased (scratched). If the current master file is destroyed or corrupted, it is reconstructed by processing the most current backup file against the corresponding transaction file.
The GFS backup method involves sequential master files. Current file updated with transactions becomes the new master, forming generations of backups.