Description
The Abort Guidance System included the following components:
- Abort Electronic Assembly (AEA): the computer
- Abort Sensor Assembly (ASA): a simple strapdown IMU
- Data Entry and Display Assembly (DEDA): the interface similar to DSKY
The computer used was MARCO 4418 (MARCO stands for Man Rated Computer) whose dimensions were 5 by 8 by 23,75 inches (12,7 by 20,3 by 60,33 centimeters); it weighed 32,7 pounds (14,83 kg) and required 90 watts of power. Because the memory had a serial access it was slower than AGC, although some operations on AEA were performed as fast or faster than on AGC.
The computer had the following characteristics:
- It had 4096 words of memory. Lower 2048 words were erasable memory (RAM), higher 2048 words served as fixed memory (ROM). The fixed and erasable memory were constructed similarly so the ratio between fixed and erasable memory was variable.
- It was an 18-bit machine, with 17 magnitude bits and a sign bit. The addresses were 13 bits long; MSB indicated index addressing.
- Data words were two's complement and in fixed-point form.
Read more about this topic: Apollo Abort Guidance System
Famous quotes containing the word description:
“To give an accurate description of what has never occurred is not merely the proper occupation of the historian, but the inalienable privilege of any man of parts and culture.”
—Oscar Wilde (1854–1900)
“Everything to which we concede existence is a posit from the standpoint of a description of the theory-building process, and simultaneously real from the standpoint of the theory that is being built. Nor let us look down on the standpoint of the theory as make-believe; for we can never do better than occupy the standpoint of some theory or other, the best we can muster at the time.”
—Willard Van Orman Quine (b. 1908)
“As they are not seen on their way down the streams, it is thought by fishermen that they never return, but waste away and die, clinging to rocks and stumps of trees for an indefinite period; a tragic feature in the scenery of the river bottoms worthy to be remembered with Shakespeare’s description of the sea-floor.”
—Henry David Thoreau (1817–1862)