Providing memory bandwidth compression using compressed memory controllers (CMCs) in a central processing unit (CPU)-based system is disclosed. In this regard, in some aspects, a CMC is configured to receive a memory read request to a physical address in a system memory, and read a compression indicator (CI) for the physical address from a master directory and/or from error correcting code (ECC) bits of the physical address. Based on the CI, the CMC determines a number of memory blocks to be read for the memory read request, and reads the determined number of memory blocks. In some aspects, a CMC is configured to receive a memory write request to a physical address in the system memory, and generate a CI for write data based on a compression pattern of the write data. The CMC updates the master directory and/or the ECC bits of the physical address with the generated CI.

A Non-Volatile Memory express (NVMe) node includes a memory used at least in part as a shared cache in a distributed cache. At least one processor of the NVMe node executes a kernel of an Operating System (OS). A request is received from another NVMe node to read data stored in the shared cache or to write data in the shared cache and an error detection operation is performed on the data for the request using the kernel. In another aspect, the kernel is used to perform Erasure Coding (EC) on data to be stored in the distributed cache. A network controller determines different EC ratios based at least in part on indications received from NVMe nodes of frequencies of access of different data and/or usage of the distributed cache by different applications. The network controller sends the determined EC ratios to the NVMe nodes.

Techniques are disclosed relating to improving memory reliability, e.g., in the context of memory circuits with limited reliability features. In some embodiments, memory controller circuitry is configured to communicate with memory circuitry via an interface that supports link error detection. The memory controller circuitry may, based on a corruption indicator, transmit a data and parity combination for the first data block that causes the memory circuitry to detect an uncorrectable write interface error. Subsequent reads of the location may therefore cause an uncorrectable error indication. This may advantageously allow the memory controller circuitry to propagate a corruption indicator as an uncorrectable error in the memory circuit, without requiring additional tracking of the indicator by the memory circuit or memory controller, in some embodiments.

A queuing requester for access to a memory system is provided. Transaction requests are received from two or more requestors for access to the memory system. Each transaction request includes an associated priority value. A request queue of the received transaction requests is formed in the queuing requester. Each transaction request includes an associated priority value. A highest priority value of all pending transaction requests within the request queue is determined. An elevated priority value is selected when the highest priority value is higher than the priority value of an oldest transaction request in the request queue; otherwise the priority value of the oldest transaction request is selected. The oldest transaction request in the request queue with the selected priority value is then provided to the memory system. An arbitration contest with other requesters for access to the memory system is performed using the selected priority value.

An apparatus for on demand access and cache encoding of repair data. In one embodiment the apparatus includes an integrated circuit having a data cache in data communication with a non-volatile memory, a controller of a built-in self-test-and-repair (BISTR) circuit, and a plurality of registers. The controller is configured to read data from the data cache and store it into a first of the plurality of registers.

Methods, systems, and devices for post error correction code (ECC) registers for cache metadata are described. A device may read metadata from a memory array included in the device. The metadata may include information for operating a volatile memory as a cache for a non-volatile memory. The device may perform an ECC operation on the metadata based on reading the metadata from the memory array. After performing the ECC operation on the metadata, the device may write the metadata to a register that is coupled with the memory array. The device may then write the metadata from the register to the memory array.

Methods, systems, and devices for methods for supporting mismatched transaction granularities are described. A memory system may include a host device the performs data transactions according to a first code word size that is different than a second code word size associated with a storage component within the memory system. A cache may be configured to receive, from the host device, a first code word associated of the first code word size and associated with a first address of the storage component. The cache may store the first code word. When the first code word is evicted from the cache, the memory system may generate a third code word of the second size based on the first code word and a second code word stored in the first address of the storage component and store the third code word at the first address of the storage component.

Provided herein is a memory device and a method of operating the same. The memory device may include a CAM block configured to store CAM data required for various operations, a page buffer group configured to store the CAM data read from the CAM block through a CAM read operation, an extra register configured to store extra data generated by performing an operation on the CAM data, an operation logic configured to perform an operation of checking a defect in the extra register, registers configured to sequentially store operation data generated through the defect check operation, a fixed register configured to store fixed data obtained through an operation performed to check an error in the CAM data, and core circuits configured to perform the CAM read operation and transmit the operation data and the CAM data to the extra register, the registers, and the fixed register.

Methods, systems, and devices for fully associative cache management are described. A memory subsystem may receive an access command for storing a first data word in a storage component associated with an address space. The memory subsystem may include a fully associative cache for storing the data words associated with the storage component. The memory subsystem may determine an address within the cache to store the first data word. For example, the memory subsystem may determine an address of the cache indicated by an address pointer (e.g., based on the order of the addresses) and determine a quantity of accesses associated with the data word stored in that cache address. Based on the indicated cache address and the quantity of accesses, the memory subsystem may store the first data word in the indicated cache address or a second cache address sequential to the indicated cache address.

A cache control apparatus includes a data unit configured to store data on an index-specific basis, a tag unit configured to store, on the index-specific basis, a tag and a flag indicating whether the data has an uncorrectable error, and a control unit configured to refer to the flag, upon detecting a tag hit by performing a read access to the tag unit, to determine whether an uncorrectable error exists in the data corresponding to the tag hit, wherein the control unit performs process scheduling such that the read access to the tag unit and another access to the tag unit are performed simultaneously.