Humanities History & Culture History of Computer Memory Definitions, Timeline Share Flipboard Email Print Random Access Memory or RAM. (Daniel Sambraus/Getty Images) History & Culture Inventions Computers & Internet Basics Famous Inventions Famous Inventors Patents & Trademarks Timelines American History African American History African History Ancient History & Culture Asian History European History Family History & Genealogy Latin American History Medieval & Renaissance History Military History The 20th Century Women's History View More by Mary Bellis Mary Bellis, known by some as CalmX, was an experimental artist, film director and producer, video game content creator, and freelance writer for some 18 years. She specialized in writing about inventors and inventions, in particular. Bellis died in March 2015. Updated April 17, 2017 Drum memory, an early form of computer memory, used the drum as a working part, with data loaded to the drum. The drum was a metal cylinder coated with a recordable ferromagnetic material. The drum also had a row of read-write heads that wrote and then read the recorded data. Magnetic core memory (ferrite-core memory) is another early form of computer memory. Magnetic ceramic rings called cores, stored information using the polarity of a magnetic field. Semiconductor memory is computer memory we are all familiar with, computer memory on an integrated circuit or chip. Referred to as random-access memory or RAM, it allowed data to be accessed randomly, not just in the sequence it was recorded. Dynamic random access memory (DRAM) is the most common kind of random access memory (RAM) for personal computers. The data the DRAM chip holds has to be periodically refreshed. Static random access memory or SRAM doesn't need to be refreshed. Timeline of Computer Memory 1834 Charles Babbage begins to build his "Analytical Engine", a precursor to the computer. It uses read-only memory in the form of punch cards. 1932 Gustav Tauschek invents drum memory in Austria. 1936 Konrad Zuse applies for a patent for his mechanical memory to be used on his computer. This computer memory is based on sliding metal parts. 1939 Helmut Schreyer invents a prototype memory using neon lamps. 1942 The Atanasoff-Berry Computer has 60 50-bit words of memory in the form of capacitors mounted on two revolving drums. For secondary memory, it uses punch cards. 1947 Frederick Viehe of Los Angeles applies for a patent for an invention that uses magnetic core memory. Magnetic drum memory is independently invented by several people. An WangAn Wang invented the magnetic pulse controlling device, the principle upon which magnetic core memory is based.Kenneth OlsenKenneth Olsen invented vital computer components, best known for "Magnetic Core Memory" Patent No. 3,161,861 and as being the co-founder of Digital Equipment Corporation.Jay ForresterJay Forrester was a pioneer in early digital computer development and invented random-access, coincident-current magnetic storage. 1949 Jay Forrester conceives the idea of magnetic core memory as it is to become commonly used, with a grid of wires used to address the cores. The first practical form manifests in 1952-53 and renders obsolete previous types of computer memory. 1950 Ferranti Ltd. completes the first commercial computer with 256 40-bit words of main memory and 16K words of drum memory. Only eight were sold. 1951 Jay Forrester files a patent for matrix core memory. 1952 The EDVAC computer is completed with 1024 44-bit words of ultrasonic memory. A core memory module is added to the ENIAC computer. 1955 An Wang was issued U.S. patent #2,708,722 with 34 claims for magnetic memory core. 1966 Hewlett-Packard releases their HP2116A real-time computer with 8K of memory. The newly formed Intel starts to sell a semiconductor chip with 2,000 bits of memory. 1968 USPTO grants patent 3,387,286 to IBM's Robert Dennard for a one-transistor DRAM cell. DRAM stands for Dynamic RAM (Random Access Memory) or Dynamic Random Access Memory. DRAM will become the standard memory chip for personal computers replacing magnetic core memory. 1969 Intel begins as chip designers and produces a 1 KB RAM chip, the largest memory chip to date. Intel soon switches to being notable designers of computer microprocessors. 1970 Intel releases the 1103 chip, the first generally available DRAM memory chip. 1971 Intel releases the 1101 chip, a 256-bit programmable memory, and the 1701 chip, a 256-byte erasable read-only memory (EROM). 1974 Intel receives a U.S. patent for a "memory system for a multichip digital computer". 1975 Personal consumer computer Altair released, it uses Intel's 8-bit 8080 processor and includes 1 KB of memory. Later in the same year, Bob Marsh manufacturers the first Processor Technology's 4 kB memory boards for the Altair. 1984 Apple Computers releases the Macintosh personal computer. It is the first computer that came with 128KB of memory. The 1 MB memory chip is developed. Continue Reading