If a disk uses GPT partitioning method, is its first sector still called MBR? What is a generic name for the sector which stores the partition table of a disk? Thanks.
A GPT partitioned disk still has a legacy MBR that is typically used to store a "Protective MBR", containing an old-fashioned partition table defining a single partition of type
EE spanning the whole disk (up to 2 TB). The purpose of this entry is to tell old tools that don't understand GPT that there is no free space on the disk, hopefully preventing the creation of legacy partitions on the disk. The MBR also contains boot code, if the firmware confirms to the legacy BIOS interface instead of UEFI.
After the MBR (Linear Block Address 1) comes the Primary GPT Header, a sector containing miscellaneous data, for example the LBA of the start of the real GPT partition table (usually LBA 2).
The GPT partition partition table spans several sectors, typically 32, but can be larger or smaller; the size is defined in the GPT Header.