Assuming you are referring to the IBM System z900 mainframe computer, the storage capacity can vary depending on the specific configuration and options selected.
The z900 uses high-speed storage technologies such as solid-state drives (SSDs) and magnetic disk drives (HDDs) to store data. The system can support various storage configurations, including internal and external storage options.
The internal storage options for the z900 include up to 32GB of main memory (RAM), which is used for active program and data storage during processing. Additionally, the z900 can support up to 136TB of disk storage, which can be divided into multiple logical partitions (LPARs) to provide secure and isolated storage for different applications or users.