A library has a physical cartridge access port (PCAP) for receiving cartridges which are to be entered/ejected into/out of the library. The library is partitioned into partitions each having a set of the library cells such that the library appears to a host as multiple libraries with each partition appearing to the host as a respective one of the multiple libraries. Some cells are reserved for use by the partitions as virtual cartridge access ports (VCAPs) which appear to the host as being the PCAP such that cartridges, which are to be ejected out of the partitions, are exported from the cells of the partitions to the VCAPs for subsequent transfer from the VCAPs to the PCAP, and such that cartridges, which are to be entered into the partitions, are imported from the VCAPs to the cells of the partitions after having been moved from the PCAP to the VCAPs.