Externally Attached Automated Libraries 363Externally Attached Automated LibrariesMulti-control path architectureAllows each tape unit in a library access to the robot arm as if it was theonly drive in the library.Multiple PartitionsThe tape library can be split into partitions. Each drive has assignedcassettes it can use.Tape pooling Tape devices can be attached to separate controllers, but the systemsoftware recognizes resources with equal capabilities in a common librarydevice. At vary on, all equal resources are displayed under the commonlibrary device description. This allows BRMS to assign jobs for a specificresource to a pool of tapes that are available under this resource.Available on OS/400 V4R5 or later.Performance The actual throughput you may achieve is a function of many components,such as system processor, disk data rate, data block size, datacompressibility, I/O attachments, and the system or application softwareused. The numbers stated here are the maximum throughput attainable bythe tape unit. The best source of information about performance is theAS/400 Performance Capabilities Reference , SC41-0607, at:http://publib.boulder.ibm.com/pubs/html/as400/online/chgfrm.htmAs a general rule, it is important to note that SCSI bus technology used by the iSeries runs at20 or 40 MB/sec. High-end tape drives can attain transfer speeds in the 30 to 45 GB/secrange, which means the throughput is that of the entire SCSI bus. Even though most tapedrives allow more tape drives connected to the same bus, this is not recommended since youwill never attain full utilization of these drives due to SCSI transfer limitations.IBM 7329 Model 308 SLR100 Tape AutoloaderThe IBM 7329 Model 308 SLR100 Tape Autoloader is a stand-aloneautomated tape backup system for use on iSeries servers. It provides mediacapacity of 400 GB (800 GB assuming 2:1 compression), automated datastorage at a rate of 5 MB per second (10 Mb per second with 2:1compression). This data rate is twice the rate of previous ¼-inch tape backup used on theiSeries.In addition to reading and writing on new SLR100 50 GB or 5 GB data cartridges, the 7329Model 308 provides backward write and read compatibility with MLR3 (SLR50) and backwardread compatibility with MLR1 (DC 5010) tape formats. Attachment to the iSeries is via a SCSIinterface adapter.
