Write-through-and-back cache

Abstract

Embodiments are provided for cache memory systems. In one general embodiment, a system that includes a storage device, and at least one storage class memory device operating as a write cache for the storage device. The storage device further includes a first storage location for data received from a host computer during a host write request and a second storage. Data received from a host write request is written to the storage class memory device, to the first location in the storage device, and to the second location in the storage device that logically reflects the location of the data in the storage class device location configured as a log structured file.

Description

BACKGROUND[0001]The present invention relates generally to computer cache memory systems, and more particularly, to a cache memory that includes aspects of write-through and write-back caches.[0002]Data may be stored and retrieved from some types of memory devices used in computer systems more rapidly than for other types of memory devices. For example, DRAM (dynamic random access memory) is relatively low in cost and has fast access. However, a disadvantage of DRAM is that is it is volatile and data stored in DRAM is lost when power is removed from the memory devices. Disk storage devices with magnetic, optical, or other types of rotating disk media are nonvolatile, have very low cost per byte of storage, and very high storage capacity. However, a disadvantage of disk storage devices is that they have relatively slow access for storing and retrieving data.[0003]To reduce access times for disk storage devices, cache memory systems may be used to hold data that has been recently read...

AI Technical Summary

Problems solved by technology

However, a disadvantage of DRAM is that is it is volatile and data stored in DRAM is lost when power is removed from the memory devices.

However, a disadvantage of disk storage devices is that they have relatively slow access for storing and retrieving data.

While flash memory devices have faster access time than disk storage devices, they are generally considered to be too expensive to be used for the entire memory space in a computer system.

The difference in latency between disk storage devices and DRAM has increased over time.

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