System and method for persistent RAM disk

• US 20080022410A1
• Filed: 07/17/2007
• Published: 01/24/2008
• Est. Priority Date: 10/31/2003
• Status: Active Grant

• Current Assignee: Superspeed Software Incorporated
• Original Assignee: Superspeed Software Incorporated
• Inventors: Diehl, Shawn
• Granted Patent: US 7,594,068 B2
• Time in Patent Office: Days
• US Class Current: 726/26
• CPC Class Codes: G06F 11/1417 Boot up procedures
• CPC Class Codes: G06F 11/1441 Resetting or repowering
• CPC Class Codes: G06F 9/4418 Suspend and resume; Hibernate and awake

Abstract

The contents of a RAM disk are copied to an image file in nonvolatile memory on power-down and copied back on reboot to provide an appearance of persistence. A locking method can use in-use tables to limit access to the same blocks of data in a RAM disk.

Claims

1. A method for protecting data from loss or corruption due to simultaneous access to a portion of memory by two different program threads, comprising:

executing a memory gating program that tracks running threads and their memory demands;

creating and managing an in-use table that includes information about which threads are using which portions of memory, and which threads are waiting to use the same portions of memory;

allowing a thread to access a given portion of memory if it is not in use by another thread as indicated by the in-use table; and

preventing a thread from accessing the given portion of memory if it is in use by another thread as indicated by the in-use table.

2. The method of claim 1, further comprising determining a sequence of dependency, whereby a first thread is kept waiting for a second thread that is using the portion of memory, the determining including administration by the memory gating program of a succession of rights to the portion of memory in an organized fashion.

3. The method of claim 1, further comprising accessing the memory in blocks sufficiently small in size so as to reduce the number of conflicts over a given memory block and to reduce the number of threads kept waiting for access to the same memory block.

4. The method of claim 3, wherein the memory blocks comprise sectors having a maximum size of about 512 bytes per sector.