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-‐‑‒ -‐‑‒
An application using NVM.FILE mode may or may not be using memory-mapped file
behavior.
The NVM.FILE mode describes NVM extensions including:
• Discovery and use of atomic write features
• The discovery of granularities (length or alignment characteristics)
4.3.3 NVM.PM.VOLUME mode overview
NVM.PM.VOLUME mode describes the behavior for operating system components (
file systems) accessing persistent memory. NVM.PM.VOLUME mode provides a soft
abstraction for Persistent Memory hardware and profiles functionality for operating sy
components including:
• the list of physical address ranges associated with each PM volume
• the capability to determine whether PM errors have been reported
Figure 5 NVM.PM.VOLUME and NVM.PM.FILE mode examples
Application
PM device PM device PM device. . .
User space
Kernel space
MMU
MappingsPM-aware file system
NVM PM capable driver
Load/
store
Native file
API
PM-aware kernel module
PM device
NVM.PM.VOLUME mode
NVM.PM.FILE mode
4.3.4 NVM.PM.FILE mode overview
NVM.PM.FILE mode describes the behavior for applications accessing persistent me
The commands implementing NVM.PM.FILE mode are similar to those using NVM.F
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Note that there are other models for connecting a non-PM file system to PM hardware.
4.3 NVM programming modes
4.3.1 NVM.BLOCK mode overview
NVM.BLOCK and NVM.FILE modes are used when NVM devices provide block storage
behavior to software (in other words, emulation of hard disks). The NVM may be exposed as a
single or as multiple NVM volumes. Each NVM volume supporting these modes provides a
range of logically-contiguous blocks. NVM.BLOCK mode is used by operating system
components (for example, file systems) and by applications that are aware of block storage
characteristics and the block addresses of application data.
This specification does not document existing block storage software behavior; the
NVM.BLOCK mode describes NVM extensions including:
• Discovery and use of atomic write and discard features
• The discovery of granularities (length or alignment characteristics)
• Discovery and use of ability for applications or operating system components to mark
blocks as unreadable
Figure 4 NVM.BLOCK and NVM.FILE mode examples
Application
NVM block capable driver
File system
Application
NVM device NVM device
User space
Kernel space
Native file
API
NVM.BLOCK mode
NVM.FILE mode
4.3.2 NVM.FILE mode overview
NVM.FILE mode is used by applications that are not aware of details of block storage
hardware or addresses. Existing applications written using native file I/O behavior should work
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STORE data[0] = 0xFOOD
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ata[0] ST CLFLUSH
CLFLUSHOPT
• Provides unordered version of CLFLUSH
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Linux – PDA
Agenda VR3 (2001)
