You hit the power button on your television and it instantly comes to life. But do the same thing with your computer and you have to wait a few minutes while it goes through its boot-up sequence. Why can't we have a computer that turns on as instantly as a television or radio? IBM, in cooperation with Infineon, is promising to launch a new technology in the next few years that will eliminate the boot-up process. Magnetic random access memory (MRAM) has the potential to store more data, access that data faster and use less power than current memory technologies.


Photo courtesy IBM
IBM researcher Stuart Parkin used this sputtering machine to create magnetic tunnel junctions, a key to MRAM technology.

If IBM can make MRAM chips small enough and cheap enough, this new technology could be in computers, cell phones and games by 2004. The key to MRAM is that, as its name suggests, it uses magnetism rather than electrical power to store data. This is a major leap from dynamic RAM (DRAM), the most common type of memory in use today, which requires a continuous supply of electricity and is terribly inefficient.

At a time when power is at a premium and electric bills are soaring, MRAM threatens to replace not only dynamic RAM, but also Flash memory. In the section of How Dewsoft Stuff Will Work, we'll examine the impact MRAM will have on the electronics industry, and find out why it has taken IBM 30 years to develop this technology.
 

Computer Memory Series

Instant-On Computing
When you turn your computer on, you can hear it revving up. It takes a few minutes before you can actually get to programs to run. If you just want to browse the Internet, you have to wait for your computer's start-up sequence to finish before you can go to your favorite Web sites. You push the computer's power button, there's some beeping and humming, you see flashes of text on the screen and you count the seconds ticking by. It's a very slow process. Why can't it simply turn on like your television? -- hit a button and instantly your Internet browser is ready to go. What is it that your computer has to do when you turn it on?

Every computer has a basic input/output system (BIOS) that performs a series of functions during the boot-up sequence. The BIOS is a type of software that your computer needs to function properly. Its most important function is to load the computer's operating system when you turn the computer on. During a cold boot, the BIOS also checks the RAM by performing a read/write test of each memory address. The first thing the BIOS does is check the information stored in a tiny amount of RAM (64 bytes) located on a complementary metal oxide semiconductor (CMOS) chip.

MRAM would eliminate the tedium of boot-up because it would use magnetism, rather than electricity, to store bits of data. MRAM will slowly begin to replace DRAM starting sometime in 2003. DRAM wastes a lot of electricity because it needs to be supplied with a constant current to store bits of data. In a DRAM configuration, a capacitor operates like a small bucket storing electrons. To store a 1 in a memory cell, the bucket is filled with electrons. To store a 0, the bucket is emptied. DRAM has to be refreshed thousands of times per second to retain a 1.

In an MRAM chip, only a small amount of electricity is needed to store bits of data. This small amount of electricity switches the polarity of each memory cell on the chip. A memory cell is created when wordlines (rows) and bitlines (columns) on a chip intersect. Each one of these cells stores a 1 or a 0, representing a piece of data. MRAM promises to combine the high speed of static RAM (SRAM), the storage capacity of DRAM and the non-volatility of Flash memory.


Photo courtesy IBM

Like Flash memory, MRAM is a nonvolatile memory -- a solid-state chip that has no moving parts. Unlike with DRAM chips, you don't have to continuously refresh the data on solid-state chips. Flash memory can't be used for instant-on PCs because it hasn't demonstrated long-term reliability. MRAM will likely compete with Flash memory in the portable device market for the same reason that it will replace DRAM -- it reduces power consumption. For users of laptops and other mobile devices, such as MP3 players and cell phones, MRAM is the holy grail of longer battery life.

Developing MRAM
Magnetic RAM is not an overnight technological feat. It has taken nearly three decades to develop. To give you an idea of when IBM began working on MRAM, Microsoft didn't even exist when IBM made its first breakthrough in this technology. In 1974, IBM Research developed a miniature computer component called the
magnetic tunnel junction. This component was eventually used to store information.

The potential market for MRAM is big. It is expected to eventually become the memory standard for future electronics, replacing DRAM. In 1999, the DRAM market was $21 billion. It's that potential market that has several companies chasing IBM to develop MRAM, including Intel, Motorola, Honeywell, Hewlett-Packard, Toshiba, Siemens and Bosch. IBM currently holds the lead in this race, holding about 15 patents that relate to MRAM. It also successfully built a working MRAM chip in 1998. The challenge now is to produce a chip that can store large amounts of data and be made for an affordable cost to consumers.

"MRAM has the potential to replace today's memory technologies in electronic products of the future," said Bijan Davari, IBM Vice President of Technology and Emerging Products. He added that the announcement of MRAM's impending availability is a major step in moving the technology from the research stage to product development.

By 2003, IBM and Infineon expect to have test chips in use. Initial chips will only be able to accommodate 256 megabytes of data. There are already some removable Flash memory chips that can hold that much data. However, IBM researchers believe that they could increase the data-storage size by the time it reaches volume production in 2004. MRAM then will be made available to consumers in limited quantities.

It will probably take at least a decade before we see MRAM chips become a mainstream storage medium. By then, who knows what we will be looking at? Holographic memory is projected to be available as early as 2003. It will be able to store 125 gigabytes and produce transfer rates of about 40 megabytes per second. The combination of MRAM and holographic memory, both being developed by IBM, could result in a desktop computer than can hold tons of data, work faster and use less power than its most high-tech predecessors.

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