An SMS term, referring to automatic class selection routine. Not to be confused with the HSC term, ACS, referring to Automatic Cartridge System.
ACSLS (Automated Cartridge System Library Software) enables Automated Tape Libraries to be shared in a heterogeneous environment and functions as the central service provider for library operations in a open-systems environment.
Automatic migration threshold. AMT values are user–defined percentage values that determine when virtual tape volume migration begins and ends. VTV migration begins when the VTSS buffer reaches the high AMT and ends when the buffer reaches or falls below the low AMT. These thresholds apply to all VTSSs.
An assembly that allows several cartridges to be inserted into or ejected from an LSM without human entry into the LSM.
Control data set. The HSC database. In addition to the current information in the CDS, VSM keeps all its persistent data in the CDS as well.
A configuration that consists of a Primary VTSS and a Secondary VTSS connected by one or more Nearlink connections (cluster links).
You can use the MGMTclas statement REPLICAT parameter (which requires the Advanced Management Feature) to direct the Primary VTSS to replicate (copy) a VTV to the Secondary VTSS via a cluster link. If the Primary VTSS becomes unavailable, you can use the VT VARY VTSS command to vary it offline to VTCS. You then vary the Secondary VTSS's VTDs online to MVS to continue the workload. The Secondary, therefore, acts as a "warm standby" to the Primary VTSS.
The movement of data from the VTSS to the RTD where VTVs are stacked onto MVCs. Migration is initiated by VSM when high AMT levels are reached. VTVs are selected for migration based on use and size: the least recently used and the largest VTVs are selected first. VSM provides the ability to migrate VTVs on demand and to migrate multiple copies of the VTV.
Multi–volume cartridge. The physical cartridge in the LSM that contains one or more VTVs or no VTVs, but has been identified as a volume that can be selected for VTV stacking. This data is stored in the CDS.
The movement of VTVs back to the VTSS from the MVC. VSM provides the ability to recall VTVs on demand.
Refers to MVC space reclamation. VTCS uses the amount of fragmented free space on the MVC and the amount of VTV data that would have to be moved to determine if space reclamation is justified. VSM provides the ability to reclaim MVCs on demand.
Real Tape Drive. The physical transport controlled by VSM/HSC. The transport has a data path to a VTSS and may optionally have a data path to MVS or to another VTSS.
Sun StorageTek Storage Management Component, which is the interface between IBM's z/OS operating systems and HSC and MVS/CSC.
Virtual Storage Manager. A storage solution that virtualizes volumes and transports in a VTSS buffer in order to improve media and transport use. The hardware includes VTSS, which is the disk buffer, and RTDs. The software includes VTCS, an HSC–based host software, and VTSS microcode.
Virtual Tape Control System. The primary host software that controls activity and information about VTSSs, VTVs, RTDs, and MVCs. This software operates in the same address space from HSC, and communicates closely with HSC.
Virtual Tape Drive. A transport in the VTSS that emulates a physical 3490E to MVS. The data written to a VTD is really being written to disk. The VTSS has 64 VTDs that do virtual mounts of VTVs.
Virtual Tape Storage Subsystem. The disk buffer containing virtual volumes and transports. The VTSS is disk device with microcode that enables emulation of 32 or 64 transports. The device can read and write "tape" data from/to disk, and can read and write the data from/to an RTD.