1.2 Multi-MS Structure

A Multi-MS (MMS) is structured to have a reference MS on the top directory and a subdirectory called SUBMSS, which contains each partitioned sub-MS. A Multi-MS can be handled like a normal monolithic MS. It can be moved and renamed like any other directory. CASA tasks that are not MMS-aware can process it like a monolithic MS. The reference MS contains links to the sub-tables of the first sub-MS. The other sub-MSs contain a copy of the sub-tables each. In order to reduce the volume of the MMS, the POINTING and SYSCAL tables (which are read-only in all use cases and identical for all sub-MSs) are stored only with the first sub-MS and linked into the other sub-MSs.

The table.info file inside the reference MS contains information on the axis used to partition the original MS. This information is written by the partition task and carried over by other tasks.