Patent Application
20090185309
1. Technical Field
The present invention relates to data storage systems in general, and more particularly, to a tape drive system. Still more particularly, the present invention relates to a method for minimizing contaminant levels within a tape drive system.
2. Description of Related Art
During the insertion of a tape cartridge into a tape drive system, contaminants, such as dust, can be pulled into the tape drive system from the loading area in which the tape cartridge is inserted. When the tape cartridge is subject to a load/unload operation, dust that has accumulated around the tape cartridge in the loading area is disturbed and may be drawn into the tape drive system by a cooling fan. The dust may eventually be deposited on a read/write tape head of the tape drive system. In time, the dust may cause the tape drive system to suffer failures due to the inability to read servo landmark information and/or read and write data.
The dust problem can be overcome by incorporating a head brush cleaning procedure at every unload/load operation. However, the head brush cleaning procedure adds extra time to every unload operation, which may be unacceptable for a library automation application, such as the IBM 3584 tape library where a robotic arm loads tape cartridges to or unloads tape cartridges from tape drives and stores tape cartridges in storage slots when they are not in tape drives.
Consequently, it would be desirable to provide a method for minimizing contaminant levels within a tape drive system.
In accordance with a preferred embodiment of the present invention, a dust concentration level within a tape drive system is initially determined. A head brush interval is subsequently adjusted according to the determined dust concentration level within the tape drive system.
All features and advantages of the present invention will become apparent in the following detailed written description.
The invention itself, as well as a preferred mode of use, further objects, and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:
With reference now to the drawings, and in particular to
With reference now to
Automation libraries use a private communication link for monitoring and controlling the removable media drives installed in them. The Automation/Drive Interface (ADI)—Transport Protocol standard, as defined by the InterNational Committee on Information Technology Standards (see http:www.t10.org), specifies a protocol for transporting commands, data, and status between automation devices and media drives. The ADI or analogous library drive interface (LDI) can also command a tape drive to enable the head brush interval (for example, every tenth unload/load operation). The head brush interval can be changed from one to a maximum value, including never brushing the tape head until a cleaning cartridge is requested by the tape drive system. Also, a dust sensor residing in the application can sense periods of high dust concentration and modify the head brush interval to compensate for the change in dust concentration. The dust sensor can be an optical sensor looking at the amount of light reflected off of tape head 103, where a dusty tape head reflects less light than a clean tape head. Such an optical dust sensor may include a light emitting diode and phototransistor (LED-PTX) pair, and the voltage output of the phototransistor give the indication of dust.
Additionally, excessive write-verify (read-after-write) errors or excessive read errors encountered by tape drive system 100 can lead to modification of the head brush interval. These write-verify and read errors are measured by the I/O channel via data written to and read from a magnetic tape by tape head 103. Other indicators of dust may include tape head 103 being unable to read the timing-based-servo written on a magnetic tape by a tape manufacturer. Still another indication of dust can be excessive usage of a cleaner cartridge by tape drive system 100.
Alternatively, a dust sensor residing in tape drive system 100 can signal tape drive microcode to modify a head brush interval to compensate for the change in dust concentration measured by the dust sensor. The head brush interval can be changed from one to a maximum value, including never brushing the head until a cleaning cartridge is requested by tape drive system 100.
A determination is made whether or not there is a load/unload operation being performed, as depicted in block 206. If no load/unload operation is detected, the process returns to block 204. Otherwise, if a load/unload operation is detected, another determination is made whether or not a counter agrees with the computed head brush interval, as shown in block 208. If the counter does not agree with the head brush interval, then the counter is incremented, as depicted in block 210, and the process returns to block 204. However, if the counter agrees with the head brush interval, then the tape head is brushed and the interval counter is reset to zero, as shown in block 209, and the process returns to block 204.
As has been described, the present invention provides a method for minimizing contaminant level within a tape drive system.
While an illustrative embodiment of the present invention has been described in the context of a fully functional tape drive system, those skilled in the art will appreciate that the software aspects of an illustrative embodiment of the present invention are capable of being distributed as a program product in a variety of forms, and that an illustrative embodiment of the present invention applies equally regardless of the particular type of media used to actually carry out the distribution. Examples of the types of media include recordable type media such as solid-state thumb drives, floppy disks, hard disk drives, CD ROMs, DVDs, HD-DVDs, Blu-Ray Disk, ultra-density optical, and transmission type media such as digital and analog communication links. These communication links may involve, including without limitation a Fibre Channel loop, Small Computer System Interface (SCSI), Internet SCSI (iSCSI), Serial Attach SCSI (SAS), Fibre Channel, SCSI over Fibre Channel, Ethernet, Fibre Channel over Ethernet (FCoE), Infiniband, and SATA (Serial ATA. over optical fibre or copper.
While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.
