The 3494 uses the 3490E Magnetic Tape System, the IBM TotalStorage Enterprise Tape System 3590, and the IBM System Storage Tape System 3592, individually or in combination (Figure 1, item  3 ). With z/OS, the tape drives are connected to the host using a tape control unit.

For a discussion of the different tape libraries (automated and manual) and the tape devices and media types supported in each library, refer to Analyzing Your Hardware Environment. Note that later generations of the 3592 (starting with the 3592 Model E07) are not supported in the 3494. The 3592 expands the storage capabilities and performance for these libraries by providing higher performance, a larger capacity cartridge, and increased reliability over previous tape systems. Inside an IBM tape library, the SMS tape software support recognizes the 3590-1 emulated devices by their real device types rather than by the drives they are emulating. This enables tape devices emulating 3590-1 (the 3590 Model B) to coexist in the same library.