# NDCTL User Guide ## Introduction `ndctl` is a utility for managing the Linux LIBNVDIMM Kernel subsystem. It is designed to work with various non-volatile memory devices (NVDIMMs) from different vendors. The LIBNVDIMM subsystem defines a kernel device model and control message interface for platform NVDIMM resources like those defined by the [ACPI v6.0](http://www.uefi.org/sites/default/files/resources/ACPI_6_0_Errata_A.PDF) NFIT (**N**VDIMM **F**irmware **I**nterface **T**able). The latest [ACPI ](http://www.uefi.org/specifications)and [UEFI ](http://www.uefi.org/specifications)specifications can be found at [uefi.org](http://www.uefi.org). Operations supported by `ndctl` include: * Provisioning capacity (namespaces) * Enumerating Devices * Enabling and Disabling NVDIMMs, Regions, and Namespaces * Managing NVDIMM Labels ## What's new in v69 This release incorporates functionality up to the 5.8 kernel. Highlights include support for 'PAPR' NVDIMMs, a build fix for zero-length array warnings in GCC10, a new option for ndctl-monitor allowing for a timeout for epoll, and misc unit test and documentation fixes. Commands: * monitor: add a new timeout option for polling list: skip region filtering if numa\_node is absent * {read,write}-infoblock: set a default alignment based on platform * list/others: support for PAPR NVDIMMs Tests: * align.sh: fix region selection, and label init expectation APIs: * ndctl\_bus\_has\_of\_node * ndctl\_bus\_is\_papr\_scm * ndctl\_region\_has\_numa --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.pmem.io/ndctl-user-guide/v69/master.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.