Emulated storage system

Abstract

A back-up storage system that emulates a sequential storage medium such as a tape and stores data on a randomly accessible storage medium, such as disk. The back-up storage system includes a randomly accessible storage medium, a front-end interface to emulate the sequential storage medium, to communicate with external devices using a protocol that supports the sequential storage medium, and to receive sequential-format data from the external devices, and a back-end interface to receive the sequential-format data from the front-end interface and to store the sequential-format data on the randomly-accessible storage medium.

1 . A method comprising acts of: 
 receiving data corresponding to a sequence of files to be stored on a sequential storage medium, the data including first data corresponding to a first file in the sequence of files and second data corresponding to a second file in the sequence of files, the first data being received prior to the second data;    storing the data corresponding to each of the files in the sequence of files on a randomly accessible storage medium;    maintaining first metadata identifying locations on the randomly accessible storage medium where the first data and the second data are stored; and    maintaining second metadata identifying an order in which the first file and the second file were received.    
     
     
         2 . The method of  claim 1 , wherein the act of maintaining the second metadata includes an act of maintaining second metadata identifying an order in which each file in the sequence of files was received.  
     
     
         3 . The method of  claim 1 , wherein the sequence of files is a first sequence of files and wherein the sequential medium is a first sequential medium, the method further comprising acts of: 
 receiving a second sequence of files to be stored on a second sequential storage medium; and    maintaining third metadata identifying that each file in the first sequence of files corresponds to the first sequential storage medium and that each file in the second sequence of files corresponds to the second sequence of files.    
     
     
         4 . A back-up storage system comprising: 
 a randomly accessible storage medium;    a front-end interface to emulate a sequential storage medium and communicate with external devices using a protocol that supports the sequential storage medium and to receive sequential-format data from the external devices; and    a back-end interface to receive the sequential-format data from the front-end interface and to store the sequential-format data on the randomly-accessible storage medium.    
     
     
         5 . The back-up storage system of  claim 4 , wherein the back-end interface converts the sequential-format data into data suitable for storage on the randomly-accessible storage medium.  
     
     
         6 . The back-up storage system of  claim 5 , wherein the sequential-format data includes a plurality of files, and wherein the back-up storage system further comprises a controller that stores first metadata identifying a relative position of each file of the plurality of files in the sequential-format data.  
     
     
         7 . The back-up storage system of  claim 6 , wherein the controller stores second metadata identifying a location on the randomly accessible storage medium where each file of the plurality of files is stored.