Question: Pleasant Valley State Prison has housed convicted murderers, including what man who foundd Namesys in 2004?

Context paragraphs:
Pleasant Valley School District (Idaho): Pleasant Valley School District #364 is a school district in the U.S. state of Idaho.  District #364 serves 9 students of greater Pleasant Valley in Owyhee County, Idaho, in one school, Pleasant Valley Elementary School.  Its administrative offices are located in Jordan Valley, Oregon.

Hans Reiser: Hans Thomas Reiser (born December 19, 1963) is an American convicted murderer, computer programmer, and entrepreneur.  He is the creator of the ReiserFS computer file system, which is contained within the Linux kernel, as well as its attempted successor, Reiser4.  In 2004, he founded Namesys, a corporation meant to coordinate the development of both file systems.

Pleasant Valley Community School District: The Pleasant Valley Community School District is a public school district in Scott County, Iowa.  Based in Bettendorf, but having a Pleasant Valley address, the district spans areas of eastern Bettendorf, as well as the outlying communities of Pleasant Valley, Riverdale and LeClaire.

Pleasant Valley State Prison: Pleasant Valley State Prison (PVSP) is a 640 acres minimum-to-maximum security state prison in Coalinga, Fresno County, California.  The facility has housed convicted murderers Sirhan Sirhan, Erik Menendez, X-Raided, and Hans Reiser, among others.

Fisher River (Montana): The Fisher River is a tributary of the Kootenay River (spelled Kootenai in the United States) in the U.S. state of Montana.  The Fisher River properly begins at the confluence of its two main tributaries, the Pleasant Valley Fisher River and the Silver Butte Fisher River.  Of the two tributaries, the Pleasant Valley Fisher River is the larger and is sometimes considered part of the Fisher River proper.  A variant name of the Fisher River is Pleasant Valley River, and a variant name of the Pleasant Valley Fisher River is Fisher River.

Pleasant Valley, Texas: Pleasant Valley is a town in Wichita County, Texas, United States.  It is part of the Wichita Falls, Texas Metropolitan Statistical Area.  The population was 336 at the 2010 census.  Pleasant Valley is also referred to as "The rural country club of Wichita County" in part because of the high demand for land and above average home prices.  This includes Pleasant Valley estates and also Horseshoe Bend estates to the southwest.

Pleasant Valley High School (Pennsylvania): Pleasant Valley High School is a midsized, rural, public high school in Brodheadsville, Pennsylvania.  The school's name was given by its founder, John C. Mills, who took it from a common name for the area of the locals.  Pleasant Valley High School is located on Route 209.  It is the sole high school operated by the Pleasant Valley School District.  The building was built in 1960 and renovated in 2005.

Pleasant Valley, Monmouth County, New Jersey: Pleasant Valley is an unincorporated community located within Marlboro Township in Monmouth County, New Jersey, United States.  The area reportedly received its name from George Washington after he went through the area in 1777.  The area is hilly and forested and is dotted by medium to large-sized residences.  Pleasant Valley Road and Reids Hill Road are main roads that pass through the area connecting to Routes 34, 79, and 520.  A large part of land which makes up Pleasant Valley was originally granted by the King of England in 1665 to the Rev. Obadiah Holmes.  In 1690, the area was settled by people of Dutch heritage and the original dominant language in the area was Low Dutch.

Pleasant Valley, Nevada: Pleasant Valley is a very small, unincorporated community in Washoe County, Nevada, United States.  The ZIP Code for Pleasant Valley is 89511.  The community is part of the Reno–Sparks Metropolitan Statistical Area, and US Route 395 runs through it, and acts as a divider between the eastern and western halves of the valley.  This is not to be confused with the Pleasant Valley near the Utah border which is considered to be a stronghold of the Mormon fundamentalist sect, the Apostolic United Brethren.

St. John's Regional Medical Center (California): St. John's Regional Medical Center is a hospital located in Oxnard, California in the United States, and is operated by Dignity Health, along with its sister hospital, St. John's Pleasant Valley Hospital in Camarillo, California.  The hospital was founded in 1912.  St. John's Regional Medical Center and St. John's Pleasant Valley Hospital offer comprehensive medical services, including 24-hour emergency medical and surgical services and care, cancer and oncology care and support, cardiovascular care, community outreach and screenings, diagnostic imaging services, laboratory services, maternity and women's services, neonatal intensive care, palliative care, patient and family education, rehabilitation services, spine and orthopedic care, weight loss surgery, wound healing and oxygen therapy, and more.  Together, St. John's Regional Medical Center and St. John's Pleasant Valley Hospital represent the largest acute-care health organization in Ventura County.  St. John's hospitals serve all of Ventura County and beyond, including the cities of Camarillo, Moorpark, Oxnard, Port Hueneme, Ventura, and Somis.

Supporting paragraphs: Pleasant Valley State Prison Hans Reiser
Answer: Hans Thomas Reiser