Tape library
An English tape library , also known as a tape robot , tape silo , tape jukebox or German tape library , is a device or facility that contains one or more tape drives and several magnetic tapes that the device automatically inserts into the tape drive or drives .
Small tape libraries (also called autoloaders ) have only one drive and 5 to 17 slots , so-called slots , for one tape each, which is moved to the drive with the help of a change mechanism. Such libraries usually have to interrupt their operations when tapes (often in a magazine) are to be changed. In larger tape libraries, robots designed for this purpose , so-called pickers or hand-bots , take over the transport from the slot to the drives. For this purpose, the pickers run on fixed rails. The tapes have a barcode sticker for clear identification , which is read by the picker. The changing of tapes during operation enables special slots for inserting or ejecting tapes.
As a demarcation, a virtual tape library uses one or more disk arrays for data storage instead of tape drives , but externally emulates a tape library and thus allows the same backup software to be used as with a regular tape library.
application
Large amounts of data can be backed up with tape libraries . The change of tapes is controlled by the backup software. The barcodes of the tapes are also passed on to the software, which then takes over the media management. An internal database records which backup object (e.g. a file or a hard disk image ) was backed up to which tapes.
capacity
Large tape libraries can be expanded to capacities of several thousand slots and dozen of drives. Examples are the IBM 3584 with 192 drives and 6260 slots and the SUN / STK SL 8500 with 64 drives and 10,080 slots, such as the ABBA / 2 (or ABBA / 2) originally developed in Germany by GRAU Storage Systems from Böhmenkirch (now Quantum Corporation ). AML / 2), which can hold approx. 400 drives and over 76,000 media (each fully expanded, as of the end of 2006).
To give an example of the data capacity of such a device: The Powder Horn 9310 Tape Library Company StorageTek stored in full configuration at each 6000 inserts in 24 LSMs ( English Library Storage Module ) total of up to 28.8 petabytes corresponding to 28,800 terabyte of data . The maximum capacity of large tape libraries already exceeded the limit of 1000 petabytes (1 exabyte) in 2011.
literature
- Larry Coyne, Simon Browne, Michael Engelbrecht: IBM Tape Library Guide for Open Systems . IBM Redbooks, 2017, ISBN 978-0-7384-4269-3 .