(1) (
Multiple
Bit
Rate) See
adaptive streaming.
(2) (
Master
Boot
Record) The first sector of the primary storage partition in a BIOS-based computer. The MBR contains a small program and the partition table. When the program is executed, it determines which partition contains the active operating system and branches to the boot program in that partition's boot sector to load it. See
boot sector.
From BIOS/MBR to UEFI/GPT
The PC's BIOS firmware and MBR partition table were superseded by the UEFI firmware and GUID partition table (GPT). The GPT allows unlimited partitions as large as 18 exabytes each (Windows supports up to 128 partitions). In addition, there is only one instance of the MBR partition table, whereas the GPT creates a copy at the end of the partition. See
BIOS and
UEFI.