Patent Publication Number: US-2002006006-A1

Title: Magnetic tape library apparatus

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Technical Field of the Invention  
       [0002] The present invention relates to a magnetic tape library apparatus provided with a magnetic tape drive with a self loading function by using a Load command, and particularly to a tape library apparatus wherein a carrier for carrying the tape cartridge may come into contact with the tape cartridge pushed out from the magnetic tape drive.  
       [0003] 2. Description of the Prior Art  
       [0004] In a conventional tape library apparatus, a carrier for carrying the tape cartridge may possibly interfere with, or come into contact with the tape cartridge pushed out from the magnetic tape drive.  
       [0005]FIGS. 6A to  6 I are plan views of above-mentioned carrier for explaining its moving path.  
       [0006] Further, a possible interference or collision is illustrated in FIG. 4B.  
       [0007] The carrier moves between a tape and a tape cartridge container, when the tape cartridge is pushed in the tape drive as shown in FIGS. 6A to  6 E and the tape cartridge is pushed out from the tape drive as shown in FIGS. 6F to  6 I.  
       [0008] The carrier collides with the tape cartridge at the interference portion as shown in FIG. 4B, when the carrier approaches the tape drive, after the ejection of the tape cartridge from the tape drive.  
       [0009] Therefore, the conventional magnetic tape library apparatus has a disadvantage that the tape cartridge ejected from the tape drive can not be taken into the carrier, when the carrier approaches the tape drive.  
       [0010] The tape cartridge library system as disclosed in JP 01-307965 A (1989) shortens an access time, when one of the cartridge is selected for write-in and read-out of data. Therefore, it is different from the present invention.  
       [0011] The auto-loading mechanism for a cartridge drive apparatus as disclosed in JP 09-231657 A (1997) loads automatically the cartridge again after completing ejecting the cartridge, thereby improving an operability of the auto-loading. Therefore, it is different from the present invention.  
       SUMMARY OF THE INVENTION  
       [0012] An object of the present invention is to prevent the collision between the carrier and the ejected tape cartridge by issuing a load command for leaving temporarily the tape cartridge in the tape drive.  
       [0013] In general, the magnetic tape library apparatus of the present invention is provided with a drive with a self-loading function by using a load command wherein a tape cartridge ejected from the drive interferes with a path of a carrier for the tape cartridge.  
       [0014] The magnetic tape library apparatus comprises: a tape cartridge container for storing tape cartridges; a drive for ejecting a tape cartridge, when the tape cartridge is recovered back to the tape cartridge container; a carrier for transporting the tape cartridge between the tape cartridge container and the drive; and a CPU for issuing an load command, when the tape cartridge is to be ejected from the drive, and for moving the carrier to a front position of the drive, after confirming that the tape cartridge is temporarily taken into the drive on the basis of the load command.  
       [0015] Further, the timing control method for the magnetic tape library apparatus of the present comprises the steps of: issuing a load command is issued for drive; confirming that the tape cartridge to be ejected has been brought back into drive on the basis of the issued load command; moving the carrier to a front position of drive; issuing an unload command is issued for drive; confirming that the tape cartridge has been ejected from the drive on the basis of the unload command; taking the ejected cartridge into the carrier; and moving the carrier to the object slot in order to carry the tape cartridge into an object slot in the tape cartridge container.  
       [0016] Furthermore, the recording medium of the present invention is a recording medium for storing a computer program for controlling above-mentioned magnetic tape library apparatus of the present invention.  
       [0017] As described above, a tape cartridge to be ejected from a tape drive is brought back temporarily into the tape drive on the basis of a load command. Therefore, according to the present invention, a timing lag between carrier movement and cartridge ejection is prevented, thereby avoiding a collision between the carrier and the cartridge. Therefore, the ejected cartridge is taken into the carrier without fail.  
       BRIEF EXPLANATION OF THE DRAWINGS  
       [0018]FIG. 1 is a block diagram of the magnetic tape library of the present invention.  
       [0019]FIG. 2 is a flow chart of tape cartridge ejection in the magnetic tape library of the present invention.  
       [0020]FIG. 3 is a block diagram for explaining an issue process of commands from CPU to tape drive in the magnetic tape library apparatus as shown in FIG. 1.  
       [0021]FIGS. 4A and 4B are plan views of the magnetic tape library apparatus for explaining the interference between the ejected tape cartridge and the carrier mechanism.  
       [0022]FIG. 5 is a block diagram of the magnetic tape library apparatus with a recording medium for recording a computer program for controlling the drive and carrier.  
       [0023]FIGS. 6A to  6 I are plan views of a conventional magnetic tape library apparatus for explaining a moving path of a tape carrier mechanism. 
     
    
    
     PREFERRED EMBODIMENT OF THE INVENTION  
     [0024]FIG. 1 is a block diagram of the magnetic tape library apparatus of the present invention.  
     [0025] The magnetic tape library apparatus as shown in FIG. 1 comprises CPU  10 , interface controller  11 , drive  12 , carrier  13  and tape cartridge container  14 .  
     [0026] CPU  10  comprises load command control means  101 , carrier control means  102  and unload command control means  103 .  
     [0027] Interface controller  11  executes an interface between CPU  10  and drive  12 , concerning with an issue and acquisition of commands. Interface controller  11  may be SCSI (small computer system interface) controller, or RS-422 (recommended standard-422) controller, as shown in FIG. 3.  
     [0028] Tape cartridge container  14  comprises a removable magazine rack and a fixed cell. A plurality of slots, each of which contains a tape cartridge, are provided for the magazine rack and fixed cell.  
     [0029]FIG. 2 is a flow chart for ejecting the tape cartridge from drive  12 . The ejection process comprises the steps of issuing step  201  for issuing a load command, confirming step  202  for confirming whether the tape cartridge has been contained, moving step  203  for moving the carrier toward the drive  12 , issuing step  204  for issuing an unload command, confirming step  205  for confirming whether the tape cartridge has been ejected from the drive  12 , taking-in step  206  for taking in the tape cartridge and moving step  207  for moving the carrier toward an object slot.  
     [0030]FIG. 3 is a block diagram for explaining the issue of commands from CPU  10  to drive  12 , when the tape cartridge is ejected.  
     [0031]FIG. 4A is a plan view of the magnetic tape library apparatus, when the tape cartridge does not interfere with the carrier, while FIG. 4B is a plan view of the magnetic tape library apparatus, when the tape cartridge interferes with the carrier.  
     [0032] Next, the whole sequence of the ejection and movement of the tape cartridge from drive  12 , referring to FIGS.  1  to  4 B.  
     [0033] As shown in FIG. 3, load command control means  101  in CPU  10  issues a load command at step  201 , when a tape cartridge loaded in drive  12  is to be ejected. The load command may be supported by SCSI or RS-422.  
     [0034] Drive  12  receives the load command through interface controller  11  such as SCSI or RS-422B and takes back the tape cartridge temporarily into drive  12 .  
     [0035] Load command control means  101  confirms through interface controller  11  that the tape cartridge has been brought back perfectly into drive  12 , at step  202 .  
     [0036] After step  202 , carrier control means  102  in CPU  10  moves carrier  13  from the present position to the front of drive  12 , thereby standing by an ejection of the tape cartridge at step  203 .  
     [0037] Next, as shown in FIG. 3, unload command control means  103  in CPU  10  issues an unload command at step  204 . The unload command may be supported by interface controller such as SCSI or RS-422.  
     [0038] Drive  12  receives the unload command through interface controller  11  and ejects the tape cartridge on the basis of the unload command.  
     [0039] Unload command control means  103  confirms through interface controller  11  that the tape cartridge has been properly ejected from drive  12  at step  205 .  
     [0040] After step  205 , carrier control means  102  takes in the tape cartridge ejected from drive  12  into carrier  13  at step  206 .  
     [0041] Finally, carrier control means  102  moves the carrier  13  toward an object slot in tape cartridge container  14  at step  207 , thereby recovering the tape cartridge into the object slot.  
     [0042] Thus, the interference between the tape cartridge and carrier  13  as shown in FIG. 4B is avoided.  
     [0043]FIG. 5 is a block diagram of the magnetic tape library provided with a recording medium for recording a computer program, thereby operating the magnetic tape library.  
     [0044] As shown in FIG. 5, recording medium  50  storing a computer program for tape cartridge ejection is added to the magnetic tape library apparatus as shown in FIG. 1. Recording medium  50  may be a magnetic disc, semiconductor memory.  
     [0045] The computer program for tape cartridge ejection is read out from recording medium  50  to CPU  10 , thereby controlling load command control means  101 , carrier control means  102  and unload command control means  103 . CPU  10  is operated by the computer program.