Microsoft Reserved Partition
Encyclopedia
The Microsoft Reserved Partition, or MSR, is a partition on a data storage device
that is labelled with Globally Unique Identifier
(GUID) equal to E3C9E316-0B5C-4DB8-817D-F92DF00215AE. The containing storage device has to use the new GUID Partition Table
(GPT) format, not the traditional master boot record
(MBR) partition table format. Microsoft Reserved Partition is used to reserve space ahead of time for other use, and it does not contain any meaningful data itself.
Microsoft requires an MSR on every GPT disk, and recommends it to be created as the disk is initially partitioned. It should be located after the EFI System Partition
(ESP) and any OEM
service partitions, but—most importantly—the first data partition must follow it. Initial size of MSR is 32 MB
on disks smaller than 16 GB
, or 128 MB on other disks, although it may later automatically shrink on behalf of other partitions, for example during the conversion from basic disk to dynamic disk.
Data storage device
thumb|200px|right|A reel-to-reel tape recorder .The magnetic tape is a data storage medium. The recorder is data storage equipment using a portable medium to store the data....
that is labelled with Globally Unique Identifier
Globally Unique Identifier
A globally unique identifier is a unique reference number used as an identifier in computer software. The term GUID also is used for Microsoft's implementation of the Universally unique identifier standard....
(GUID) equal to E3C9E316-0B5C-4DB8-817D-F92DF00215AE. The containing storage device has to use the new GUID Partition Table
GUID Partition Table
In computer hardware, GUID Partition Table is a standard for the layout of the partition table on a physical hard disk. Although it forms a part of the Extensible Firmware Interface standard , it is also used on some BIOS systems because of the limitations of MBR partition tables, which restrict...
(GPT) format, not the traditional master boot record
Master boot record
A master boot record is a type of boot sector popularized by the IBM Personal Computer. It consists of a sequence of 512 bytes located at the first sector of a data storage device such as a hard disk...
(MBR) partition table format. Microsoft Reserved Partition is used to reserve space ahead of time for other use, and it does not contain any meaningful data itself.
Microsoft requires an MSR on every GPT disk, and recommends it to be created as the disk is initially partitioned. It should be located after the EFI System Partition
EFI System Partition
The EFI System partition is a partition on a data storage device that is used by machines that adhere to the Extensible Firmware Interface. It contains the boot loader programs for all operating systems installed on the device, device driver files for other devices, and system utility programs...
(ESP) and any OEM
Original Equipment Manufacturer
An original equipment manufacturer, or OEM, manufactures products or components that are purchased by a company and retailed under that purchasing company's brand name. OEM refers to the company that originally manufactured the product. When referring to automotive parts, OEM designates a...
service partitions, but—most importantly—the first data partition must follow it. Initial size of MSR is 32 MB
Megabyte
The megabyte is a multiple of the unit byte for digital information storage or transmission with two different values depending on context: bytes generally for computer memory; and one million bytes generally for computer storage. The IEEE Standards Board has decided that "Mega will mean 1 000...
on disks smaller than 16 GB
Gigabyte
The gigabyte is a multiple of the unit byte for digital information storage. The prefix giga means 109 in the International System of Units , therefore 1 gigabyte is...
, or 128 MB on other disks, although it may later automatically shrink on behalf of other partitions, for example during the conversion from basic disk to dynamic disk.
See also
- Basic data partitionBasic Data PartitionIn Microsoft operating systems, when using basic disk partitioned with GUID Partition Table layout, a basic data partition is any partition identified with Globally Unique Identifier of EBD0A0A2-B9E5-4433-87C0-68B6B72699C7....
(BDP) - EFI System PartitionEFI System PartitionThe EFI System partition is a partition on a data storage device that is used by machines that adhere to the Extensible Firmware Interface. It contains the boot loader programs for all operating systems installed on the device, device driver files for other devices, and system utility programs...
(ESP)