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## Virtual tape drives 

The TS7700 presents a tape drive image of a 3490 C2A, which is identical to the IBM Virtual Tape Server (VTS) and peer-to-peer (PTP) subsystems. Command sets, responses to inquiries, and accepted parameters match the defined functional specifications of a 3490E drive. Depending on the machine model and installed features, this collection can contain up to 31 LCUs and 496 virtual drives. Virtual drives are organized in groups of 16 drive addresses under a single LCU address. 

## 4.3.2 Software requirements 

The TS7700 is supported at z/OS V2R2 or later (earlier release level support must be done through the RPQ process). For more information about the support that is provided for the specified releases of the TS7700, see the following APARs: 

GLYPH<SM590000> APAR OA37267 for Release 2.1. 

GLYPH<SM590000> No other host software support is provided for Release 3.0. 

GLYPH<SM590000> APAR OA40572 for Release 3.1. 

GLYPH<SM590000> APAR OA44351 is advised for Release 3.2. 

GLYPH<SM590000> APAR OA47487 is advised for Release 3.3. 

GLYPH<SM590000> APAR OA49373 is advised for Release 4.0. 

GLYPH<SM590000> APAR OA52376 is advised for Release 4.1.2 (some of the enhancements that are software-only can also be used with previous release levels). 

GLYPH<SM590000> APAR OA55481 is not required for Release 4.2, but recommended if the client enables TS7700 Cloud Storage Tier. 

In general, install the host software support. For more information about software maintenance, see the VTS, PTP, and 3957 Preventive Service Planning (PSP) topics at the IBM Support and Downloads web page. 

## 4.3.3 System-managed storage tape environments 

System-managed tape enables you to manage tape volumes and tape libraries according to a set of policies that determine the service to be given to the data sets on the volume. 

The automatic class selection (ACS) routines process every new tape allocation in the system-managed storage (SMS) address space. The production ACS routines are stored in the active control data set (ACDS). These routines allocate to each volume a set of classes (DC, SC, MC, and SG) that reflect your installation’s policies for the data on that volume. 

The ACS routines are started for every new allocation. Tape allocations are passed to the OAM, which uses its Library Control System (LCS) component to communicate with the Integrated Library Manager. 

