Methods for managing data writes and reads to a hybrid solid-state disk drive
View Patent ↗A method for writing data to a solid-state disk having a first portion of solid-state memory of a volatile nature and a second portion of solid-state memory of a non-volatile nature, and a controller for controlling data operations to the memory includes acts of (a) receiving at the controller, write data for writing to an assigned address in non-volatile memory; (b) determining at the controller if there is existing data associated with a write address in volatile memory, the write address referencing the assigned address in volatile memory; and (c) upon finding data in volatile memory held for the assigned write address or not at act (b), writing the data into the volatile memory at a predestinated write address in volatile memory.
1. A method for managing reads and writes in a solid-state drive having a volatile memory portion and a non-volatile memory portion, comprising the steps of:
(a) upon receiving a write request including an address and data, determining if the address is referenced at a first location in the volatile memory portion, and if so, overwriting any data at the first location, and if not, writing the data to a second location marked as available for writing in the volatile portion, and associating that location with the address;
(b) upon receiving a read request including an address, determining if the address is referenced at a location in the volatile portion, and if so, reading data from that location, and if not, reading data from the address in the non-volatile portion; and
(c) periodically comparing valid data volume in the volatile memory portion with a preset threshold, and upon exceeding the threshold, selecting data that has been longest in the volatile memory portion without alteration, moving that data from the volatile to the non-volatile portion, and marking the locations from which the data is moved as available for writing in the volatile portion.
2. The method of claim 1 wherein in step (a), the address is a logical block address (LBA) tabled in a Flash LBA table held in a reserved portion of the volatile memory.
3. The method of claim 2 wherein in step (b), the determination is made by looking for a reference to a LBA in volatile memory in the Flash LBA table at the assigned LBA entry in the table.
4. The method of claim 3 wherein in step (b), the LBA is determined by a pointer pointing to the LBA of data in a RAM LBA table held in a reserved portion of the volatile memory and the volatile memory is RAM or a variation thereof.
5. The method of claim 3 wherein in step (b), if previous data was found in memory for the assigned Flash LBA, then the RAM LBA entry in the Ram LBA table associated to the previous data written is updated to invalidate the previous data.
6. The method of claim 1 wherein the non-volatile memory is one of a NAND Flash memory or another type of non-volatile storage.
7. The method of claim 1 wherein in step (c), the data is held in the volatile memory until one or more trigger events cause the data to be moved into the non-volatile memory.
8. The method of claim 1 , further including step (d) for repeating step (c) according to the conditions until a predetermined minimum threshold value of data in volatile memory is realized.