Manchester Mark 1
（重定向自Manchester Mark I）
![The Manchester Mark 1 was one of the world's first stored-program computers.](/Images/godic/202501/25/Manchester_Mark22547.jpg")
![Functional schematic showing the Williams tubes in green. Tube C holds the current instruction and its address; A is the accumulator; M is used to hold the multiplicand and the multiplier for a multiply operation; and B contains the index registers, used to modify instructions.](/Images/godic/202501/25/MM1Schematic.svg2547.png")
![Section of punched tape showing how one 40-bit word was encoded as eight 5-bit characters.](/Images/godic/202501/25/MM1PaperTapeEncoding.svg2547.png")
The Manchester Mark 1 was one of the earliest stored-program computers, developed at the Victoria University of Manchester from the Small-Scale Experimental Machine (SSEM) or "Baby" (operational in June 1948). It was also called the Manchester Automatic Digital Machine, or MADM. Work began in August 1948, and the first version was operational by April 1949; a program written to search for Mersenne primes ran error-free for nine hours on the night of 16/17 June 1949.