LARRY WILLIAM WOODMAN
Pilots at Gebig Rd, Nottingham, NH

6026475, Feb 15, 2000

Nov 26, 1997

8/978932

Larry William Woodman - Nottingham NH

Digital Equipment Corporation - Houston TX

G06F 1200

711202

A method and apparatus for dynamically updating virtual to physical address mappings in order to reduce cache thrashing is disclosed in an example computer system having a memory apportioned into a number of pages. A cache is included in the computer system to store a subset of the pages of memory. Each of the pages of memory is addressed by a physical address that includes a cache page address portion. The pages of cache memory are accessed using a cache page address, which corresponds to the cache page address portion of the physical address of a corresponding page of memory. The disclosed system monitors the activity of virtual addresses and uses the activity of virtual addresses to increment cache page address activity counters. The cache page address activity counters are monitored to identify those cache page addresses that are frequently being accessed within a process to identify potential performance problems, such as thrashing. When a cache page address activity count has exceeded a pre-determined threshold, a virtual address associated with that cache page address is mapped to a different physical address having a different cache page address.

6016529, Jan 18, 2000

Nov 26, 1997

8/978940

Larry William Woodman - Nottingham NH

Digital Equipment Corporation - Houston TX

G06F 1730

711 3

In a computer system, a data structure is provided in memory for storing one or more data files from an external device. The data files stored in the data structure are accessible by a number of processes executing in the computer system. The computer system includes a storage device such as a cache for storing data from a subset of pages of the memory. Each of the pages of the cache is referred to as a cache page, having an associated cache page address. A physical address is allocated for storing each page of a retrieved data file stored in the data structure such that a cache page address portion of the physical address is selected from the available cache page addresses. The physical address is further selected such that the cache page addresses are substantially evenly distributed amongst the pages of the retrieved data file and the data structure in order to minimize thrashing in the cache and enhance performance.

5996055, Nov 30, 1999

Nov 26, 1997

8/979738

Larry William Woodman - Nottingham NH

Digital Equipment Corporation - Houston TX

G06F 1210

711203

A method and apparatus for reclaiming a page of physical memory in a computer system for subsequent mappings to a virtual address is provided in a system wherein the physical memory is apportioned into a number of pages. The computer system includes a temporary storage device, such as a cache, for storing a subset of the pages in memory. Each of the pages stored in the cache are accessed using a cache page address. Virtual addresses are mapped to physical addresses responsive to monitoring use of the cache page addresses associated with the allocated physical addresses. According to the present invention, a page of physical memory is reclaimed such that a substantially even distribution of cache page addresses is maintained in physical addresses of both mapped and available pages of memory. Pages are originally placed on the clean list in response to characteristics of each page including the cache page address of the page. Pages are also selected from the clean list for reclaiming based on their cache page addresses, such that the reclaiming of a page with that cache page address provides an even distribution of cache page addresses both in use in the system and available for subsequent mappings of virtual addresses.

2013013, May 30, 2013

Nov 30, 2011

13/307970

Larry Woodman - Nottingham NH, US
Prarit Bhargava - Somerville MA, US
Andrew D. Gospodarek - Raleigh NC, US

G06F 21/00, G06F 15/16

726 4, 709217

Methods and systems for secure network system request (sysrq) via Internet Control Message Protocol (ICMP) are described. A remote computing system sends a query over a network to a target computing system and determines whether the target computing system is non-responsive to the query. When the target computing system is non-responsive to the query, the remote computing system sends an ICMP request to the target computing system over the network. The ping request includes a command to be performed by the target computing system and a key to verify authorization to perform the command.