Computer History Museum

The Computer History Museum (CHM) is a museum established in 1996 in Mountain View, California, US. The Museum is dedicated to preserving and presenting the stories and artifacts of the information age, and exploring the computing revolution and its impact on society.

History

The museum's origins date to 1968 when Gordon Bell began a quest for a historical collection and, at that same time, others were looking to preserve the Whirlwind computer. The resulting Museum Project had its first exhibit in 1975, located in a converted coat closet in a DEC lobby. In 1978, the museum, now The Digital Computer Museum (TDCM), moved to a larger DEC lobby in Marlborough, Massachusetts. Maurice Wilkes presented the first lecture at TDCM in 1979 – the presentation of such lectures has continued to the present time.

TDCM incorporated as The Computer Museum (TCM) in 1982. In 1984, TCM moved to Boston, locating on Museum Wharf.

In 1996/1997, The TCM History Center (TCMHC) in Silicon Valley was established; a site at Moffett Field was provided by NASA (an old building that was previously the Naval Base furniture store) and a large number of artifacts were shipped there from TCM.

Mountain View

Mountain View may refer to any of the following places:

Canada

South Africa

United States of America

Pyruvate dehydrogenase phosphatase

pyruvate dehyrogenase phosphatase catalytic subunit 1 (PDPC 1), also known as protein phosphatase 2C, is an enzyme that in humans is encoded by the PDP1gene. PDPC 1 is an enzyme which serves to reverse the effects of pyruvate dehydrogenase kinase upon pyruvate dehydrogenase.

Function

Pyruvate dehydrogenase (E1) is one of the three components (E1, E2, and E3) of the large pyruvate dehydrogenase complex. Pyruvate dehydrogenase kinases catalyze phosphorylation of serine residues of E1 to inactivate the E1 component and inhibit the complex. Pyruvate dehydrogenase phosphatases catalyze the dephosphorylation and activation of the E1 component to reverse the effects of pyruvate dehydrogenase kinases. Pyruvate dehydrogenase phosphatase is a heterodimer consisting of catalytic and regulatory subunits. Two catalytic subunits have been reported; one is predominantly expressed in skeletal muscle and another one is much more abundant in the liver. The catalytic subunit, encoded by this gene, is the former, and belongs to the protein phosphatase 2C (PP2C) superfamily. Along with the pyruvate dehydrogenase complex and pyruvate dehydrogenase kinases, this enzyme is located in the mitochondrial matrix.

Computer

A computer is a general purpose device that can be programmed to carry out a set of arithmetic or logical operations automatically. Since a sequence of operations can be readily changed, the computer can solve more than one kind of problem.

Conventionally, a computer consists of at least one processing element, typically a central processing unit (CPU), and some form of memory. The processing element carries out arithmetic and logic operations, and a sequencing and control unit can change the order of operations in response to stored information. Peripheral devices allow information to be retrieved from an external source, and the result of operations saved and retrieved.

Mechanical analog computers started appearing in the first century and were later used in the medieval era for astronomical calculations. In World War II, mechanical analog computers were used for specialized military applications such as calculating torpedo aiming. During this time the first electronic digital computers were developed. Originally they were the size of a large room, consuming as much power as several hundred modern personal computers (PCs).

PDP-1

The PDP-1 (Programmed Data Processor-1) was the first computer in Digital Equipment Corporation's PDP series and was first produced in 1959. It is famous for being the computer most important in the creation of hacker culture at MIT, BBN and elsewhere. The PDP-1 was also the original hardware for playing history's first game on a minicomputer, Steve Russell's Spacewar!.

Description

The PDP-1 used an 18-bit word size and had 4096 words as standard main memory (equivalent to 9,216 eight-bit bytes, though the system actually used six-bit bytes), upgradable to 7004655360000000000♠65536 words. The magnetic core memory's cycle time was 5 microseconds (corresponding roughly to a "clock speed" of 200 kilohertz); consequently most arithmetic instructions took 10 microseconds (100,000 operations per second) because they used two memory cycles: one for the instruction, one for the operand data fetch. Signed numbers were represented in one's complement. The PDP-1 had computing power roughly equivalent to a 1996 pocket organizer and a little less memory.