Virtual memory device (VMD) application/driver with dual-level interception for data-type splitting, meta-page grouping, and diversion of temp files to ramdisks for enhanced flash endurance

摘要

A Virtual-Memory Device (VMD) driver and application execute on a host to increase endurance of flash memory attached to a Super Enhanced Endurance Device (SEED) or Solid-State Drive (SSD). Host accesses to flash are intercepted by the VMD driver using upper and lower-level filter drivers and categorized as data types of paging files, temporary files, meta-data, and user data files, using address ranges and file extensions read from meta-data tables. Paging files and temporary files are optionally written to flash. Full-page and partial-page data are grouped into multi-page meta-pages by data type before storage by the SSD. ramdisks and caches for storing each data type in the host DRAM are managed and flushed to the SSD by the VMD driver. Write dates are stored for pages or blocks for management functions. A spare/swap area in DRAM reduces flash wear. Reference voltages are adjusted when error correction fails.

主权项

1. A Virtual-Memory Device (VMD) driver for executing on a host comprising:
a file type identifier for generating a data type for a host write received by the VMD driver; a data split manager for sorting host write data based on the data type generated by the file type identifier; a data write cache for storing host write data having a user data type; a meta-data cache for storing host write data having a meta-data data type; a paging cache for storing host write data having a paging file data type; a temp cache for storing host write data having a temp data type; a user grouping engine for grouping user data stored in the data write cache into user meta-pages; a meta-data grouping engine for grouping meta-data data stored in the data write cache into meta-data meta-pages; and an output buffer for sending grouped meta-pages and data type information to a flash drive system for storage.