Logical block protection for tape interchange

Abstract

A two part process is used for modifying records to be written and retrieved from tape devices. A record is appended with a cyclic redundancy check and a string of zeros. Submitting the entire record to tape drives which are logical block protection enabled will result in no change. For drives that are not LBP enabled, the string of zeros at the end of the record is removed. In addition to determining whether a drive is LBP compliant, a determination may be made as to whether a drive is a linear tape open drive from a particular manufacturer. Linear tape open drives may behave similarly as drives which may not be enabled with logical block protection.

1 . (canceled) 
     
     
         2 . A method for storing data on tape media, the method comprising:
 identifying that a first tape drive supports logical block protection (LBP), wherein a first tape media resides at the first tape drive;   issuing a read command to the first tape drive to read a first record stored at the first tape media;   receiving the first data record and data associated with the first record stored at the first tape media, wherein the data associated with the first record stored at the first tape media includes a field of zeros associated with the first record;   receiving updated data to write to the first record at the first tape media;   appending a field of zeros to the updated data that are associated with the updated data;   issuing a write command to the first tape drive to write updated data with the appended field of zeros to the first data record stored at the first tape media, and   sending the updated data with the appended field of zeros to the first tape drive, wherein the first tape drive writes the updated data with the appended field of zeros to the first data record at the first tape media.   
     
     
         3 . The method of  claim 2 , wherein the data read from the first data record also has cyclic redundancy check (CRC) bytes appended to the first data record, and the method further comprising:
 stripping the CRC bytes from the first data record after receiving the first data record and the data associated with the first data record;   performing an error check of the first data record, wherein error check of the first data record is performed via the CRC bytes stripped from the first data record; and   identifying that the first data record read from the first tape drive does not include an error based on the error check; and   providing the first data record to an application program based on the first data record not including an error.   
     
     
         4 . The method of  claim 2 , further comprising:
 creating a CRC to append to the updated data record; and   appending the CRC to the updated data record before sending the updated data with the appended CRC and the appended field of zeros to the first tape drive.   
     
     
         5 . The method of  claim 2 , further comprising receiving the update data record from an application program. 
     
     
         6 . The method of  claim 4 , further comprising:
 identifying that a second tape drive does not support LBP after the first tape media has been interchanged into the second tape drive   sending a read command to the second tape drive to read the updated first data record stored at the first tape media;   receiving the updated data record and associated data from the second tape drive, wherein the data associated with the updated data record received from the second tape drive does not include the field of zeros associated with the updated data record based on the second tape drive not supporting LBP, and the data associated with the updated data record also include the CRC associated with the updated data record;   appending a field of zeros to the updated first data record based on the second tape drive not supporting LBP;   stripping the CRC associated with the updated data record;   performing an error check of the data record according the CRC bytes associated with the updated data record;   identifying that the first data record read from the second tape drive does not include an error; and   providing the first data record to an application program based on the first data record not including an error.   
     
     
         7 . The method of  claim 6 , further comprising:
 receiving a second updated data record of the first record from the application program to write the first data record at the first tape media when the first tape media resides at the second tape drive;   generating an updated CRC based on the second updated data record; and   sending the second updated data record and other data to the second tape drive, wherein the other data includes the updated CRC and does not include a field of zeros appended to the second updated data record and the updated CRC, and the second updated data record and the updated CRC are written to the first data record of the first tape media.   
     
     
         8 . A non-transitory computer readable storage medium having embodied thereon a program executable by a processor implementing a method for storing data on tape media, the method comprising:
 identifying that a first tape drive supports logical block protection (LBP), wherein a first tape media resides at the first tape drive;   issuing a read command to the first tape drive to read a first record stored at the first tape media;   receiving the first data record and data associated with the first record stored at the first tape media, wherein the data associated with the first record stored at the first tape media includes a field of zeros associated with the first record;   receiving updated data to write to the first record at the first tape media;   appending a field of zeros to the updated data that are associated with the updated data;   issuing a write command to the first tape drive to write updated data with the appended field of zeros to the first data record stored at the first tape media, and   sending the updated data with the appended field of zeros to the first tape drive, wherein the first tape drive writes the updated data with the appended field of zeros to the first data record at the first tape media.   
     
     
         9 . The non-transitory computer readable storage medium of  claim 8 , wherein the data read from the first data record also has cyclic redundancy check (CRC) bytes appended to the first data record, and the program is further executable to:
 strip the CRC bytes from the first data record after receiving the first data record and the data associated with the first data record;   perform an error check of the first data record, wherein error check of the first data record is performed via the CRC bytes stripped from the first data record; and   identify that the first data record read from the first tape drive does not include an error based on the error check; and   provide the first data record to an application program based on the first data record not including an error.   
     
     
         10 . The non-transitory computer readable storage medium of  claim 8 , the program is further executable to:
 create a CRC to append to the updated data record; and   append the CRC to the updated data record before sending the updated data with the appended CRC and the appended field of zeros to the first tape drive.   
     
     
         11 . The non-transitory computer readable storage medium of  claim 8 , the program is further executable to receive the update data record from an application program. 
     
     
         12 . The non-transitory computer readable storage medium of  claim 11 , the program further executable to:
 identify that a second tape drive does not support LBP after the first tape media has been interchanged into the second tape drive   send a read command to the second tape drive to read the updated first data record stored at the first tape media;   receive the updated data record and associated data from the second tape drive, wherein the data associated with the updated data record received from the second tape drive does not include the field of zeros associated with the updated data record based on the second tape drive not supporting LBP, and the data associated with the updated data record also include the CRC associated with the updated data record;   append a field of zeros to the updated first data record based on the second tape drive not supporting LBP;   stripping the CRC associated with the updated data record;   perform an error check of the data record according the CRC bytes associated with the updated data record;   identify that the first data record read from the second tape drive does not include an error; and   provide the first data record to an application program based on the first data record not including an error.   
     
     
         13 . The non-transitory computer readable storage medium of  claim 12 , the program further executable to:
 receive a second updated data record of the first record from the application program to write the first data record at the first tape media when the first tape media resides at the second tape drive;   generate an updated CRC based on the second updated data record; and   send the second updated data record and other data to the second tape drive, wherein the other data includes the updated CRC and does not include a field of zeros appended to the second updated data record and the updated CRC, and the second updated data record and the updated CRC are written to the first data record of the first tape media.   
     
     
         14 . A system for storing data on tape media, the system comprising:
 a first tape drive of a plurality of tape drives;   a second tape drive of the plurality of tape drives;   a memory; and   a processor, wherein the processor executing instructions out of the memory:
 identifies that the first tape drive supports logical block protection (LBP), wherein a first tape media resides at the first tape drive, 
 issues a read command to the first tape drive to read a first record stored at the first tape media, 
 receives the first data record and data associated with the first record stored at the first tape media, wherein the data associated with the first record stored at the first tape media includes a field of zeros associated with the first record, 
 receives updated data to write to the first record at the first tape media; appending a field of zeros to the updated data that are associated with the updated data, 
 issues a write command to the first tape drive to write updated data with the appended field of zeros to the first data record stored at the first tape media, and 
 sends the updated data with the appended field of zeros to the first tape drive, wherein the first tape drive writes the updated data with the appended field of zeros to the first data record at the first tape media. 
   
     
     
         15 . The system of  claim 14 , wherein:
 the data read from the first data record also has cyclic redundancy check (CRC) bytes appended to the first data record,   the CRC bytes are stripped from the first data record after receiving the first data record and the data associated with the first data record,   an error check of the first data record is performed error via the CRC bytes stripped from the first data record,   the first data record read from the first tape drive is identified as not including an error based on the error check, and   the first data record is provided to an application program based on the first data record not including an error.   
     
     
         16 . The system of  claim 14 , wherein:
 a CRC is created to append to the updated data record, and   the CRC is appended to the updated data record before sending the updated data with the appended CRC and the appended field of zeros to the first tape drive.   
     
     
         17 . The system of  claim 14 , wherein the updated data record is received from an application program. 
     
     
         18 . The system of  claim 16 , wherein the processor:
 identifies that a second tape drive does not support LBP after the first tape media has been interchanged into the second tape drive,   sends a read command to the second tape drive to read the updated first data record stored at the first tape media,   receives the updated data record and associated data from the second tape drive, wherein the data associated with the updated data record received from the second tape drive does not include the field of zeros associated with the updated data record based on the second tape drive not supporting LBP, and the data associated with the updated data record also include the CRC associated with the updated data record,   appends a field of zeros to the updated first data record based on the second tape drive not supporting LBP,   strips the CRC associated with the updated data record,   performs an error check of the data record according the CRC bytes associated with the updated data record,   identifies that the first data record read from the second tape drive does not include an error, and   provides the first data record to an application program based on the first data record not including an error.   
     
     
         19 . The system of  claim 18 , wherein the processor:
 receives a second updated data record of the first record from the application program to write the first data record at the first tape media when the first tape media resides at the second tape drive,   generates an updated CRC based on the second updated data record, and   sends the second updated data record and other data to the second tape drive, wherein the other data includes the updated CRC and does not include a field of zeros appended to the second updated data record and the updated CRC, and the second updated data record and the updated CRC are written to the first data record of the first tape media.