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Icons of Progress
 

DRAM

The Invention of On-Demand Data

Robert Dennard’s invention greatly improved the capability of the mainframe computer and led to the development of the personal computer. Just how far and fast DRAM technology has advanced is astounding. Yet, through the decades, Dennard’s idea for a single transistor-capacitor memory cell has endured as the conceptual foundation for dynamic random access memory.

DRAM hits home

In the 1960s and early ‘70s home computers were marketed to electronics and computer enthusiasts who purchased kits requiring assembly. Soldering and piecing together the computer required a significant amount of time, and the static memory inside these machines was exceptionally slow compared to today’s standards. In 1976, computer hobbyist Steve Wozniak built a user-friendly desktop computer containing four kilobytes of DRAM. It attracted enough interest for Wozniak to join with his friend, Steve Jobs, in marketing the computer to the public and forming their own company, Apple Computer, Inc. Within a year, Wozniak had created the Apple II, improving upon his initial design by adding a faster microprocessor and more DRAM. The Apple II was the first commercially successful desktop computer built with DRAM. By 1984, sales of the Apple II reached two million.

Dawn of the PC

In the 1980s, several manufacturers competed with Apple in the growing desktop computer market. Some of the more popular models included the Commodore 64, Tandy Corporation’s (Radio Shack) TRS-80 computer and IBM’s new business model, which was marketed as a “personal computer.” Machines of this period sported from 4 to 640 kilobytes of DRAM. Dennard’s approach to RAM, with its single-transistor design, was the standard for random access memory found in the personal computer.

Advancing DRAM

In the 1990s, variations of DRAM emerged, such as fast page RAM, which used a type of data paging system for faster memory access. In the rapid evolution of the computer, speed and power were relative—and short-lived.

EDO in, data out

In the mid 1990s, software programs with rich graphics capabilities, dazzling computer games and robust operating programs such as Microsoft ® Windows ® all demanded increased speed and storage capacity. In response, Micron Technology, a Boise, Idaho, memory manufacturer, brought forth extended data out (EDO) RAM. The new form of DRAM featured a multitasking ability wherein it could read current data while accessing new information from a computer’s hard drive. With a memory of four megabytes, EDO created dramatic increases in capacity and speed.

A clockwork DRAM

As evidence of the blistering pace of change in the computer industry, EDO’s heyday lasted roughly two years. The next significant upgrade was synchronous dynamic random access memory. As its name implies, SDRAM was synchronized to a computer’s internal clock, resulting in faster processing than its asynchronous predecessors. Like EDO, SDRAM simultaneously stored and transferred data. By the year 2000, most computers being sold were equipped with SDRAM.

Twenty-first century DRAM

The new millennium brought with it the next iteration of SDRAM—double data rate synchronous dynamic random access memory (DDR). Available with either 512 megabytes or 1 gigabyte of memory, and faster than SDRAM, DDR enabled the proliferation of laptop and notebook computers. Progress in scaling continued with the introduction of DDR2 in 2003 and DDR3 in 2007. As storage and speed increased, the price of memory shrank; in 2011 the approximate cost of one megabyte of DRAM was US$0.01 compared to US$0.20 in 2002 and US$6000 in 1980.

Embedded memory

Over the past decade the global acceptance of the Internet has posed an immense challenge to keep up with the demand for increasing telecommunications capacity. This requirement funnels down to the essential component in computer information technology, namely, the semiconductor. In 2000, IBM introduced a new form of DRAM technology that would enable the manufacture of continually smaller, faster microprocessors, called embedded DRAM or eDRAM. Seven years later, the company manufactured the most advanced eDRAM to date. With a capacity of 12,000,000 bits, it stored more than three times the memory of current microprocessors. In 2010, eDRAM experienced another notable advancement with IBM’s new Cu-32 Custom Logic manufacturing technology, providing greater memory capacity and processing speed. Using a Cu-32 smartphone, a two-hour movie can be downloaded in roughly ten seconds.

DRAM today

The term computer has long been outdated and inaccurate in describing the versatile machines that have changed the world. The evolution of DRAM has brought with it a variety of applications for computers, from simple word processing to desktop publishing, from email to streaming video.
For many years microchips, loaded with DRAM, have been orders of magnitude more powerful than the first PCs. As the technology has advanced, it has also migrated from the computer motherboard to the wide range of “smart” products we rely on and enjoy today, including mobile devices, high-definition television and MP3 players, to name just a few.