Memory system graphic

University of Maryland
Memory-Systems Research

Bruce Jacob - email address -

Overview of Our Work (and FAQ)

A surprising number of researchers and designers pay little attention to the memory system, despite the fact that the memory system is typically the dominant source of both performance loss and power dissipation within a given computer system. Most academic research in computer-systems design still focuses on the microprocessor, even though the processor has not actually been a significant bottleneck for over a decade. Our research group is arguably the best academic group in the world looking at memory systems: it is our primary focus. We have developed one of the world's most accurate and modular memory-system design frameworks, currently in wide use in both industry and academia ... as a result we have deep insight into the workings of the memory system, arguably better than any other group in the world, save for a handful of very specialized groups in industry. The few companies who pay significant attention to memory-systems performance come to our group: they hire our students, they ask our advice, they use our software to design their systems, and one uses our memory-controller design in their next-generation supercomputer. Our goals include detailed understanding of the memory system, deep characterization of its behavior, exploration of novel mechanisms and technologies, and development of extremely efficient next-generation systems from very large scale to memory-systems-on-chip.

Computational Artifacts

Workloads and Their Characterization

The Studies

Brought to you by The Memory-Systems Research Consortium

Important News

-------- June 2009

Just got Dave's DDR scheduling algorithm patented:

"System and Method for Performing Multi-Rank Command Scheduling in DDR SDRAM Memory Systems." US Pat. 7,543,102 - Filed April 17, 2006 (claiming priority back to provisional patent filed April 18, 2005) - Bruce Jacob and Dave Wang, University of Maryland.

-------- Spring 2009

... and, just as quickly as they arrived on the scene, MetaRAM (more or less) is no more. Adieu.

-------- February 2008

MetaRAM is now radar-visible. Fred, Dave, and Co. are set to take over the world.

Here's a picture of one of Dave's DIMMs ...

-------- June 2007


Our book, representing over a hundred person-years of research and accumulated knowledge (and several years' worth of writing), is due out at the end of the summer:

  • Memory Systems: Cache, DRAM, Disk. Bruce Jacob, Spencer W. Ng, and David T. Wang, with contributions by Samuel Rodriguez. ISBN 978-0-12-379751-3. Morgan Kaufmann Publishers, September 2007. Approx. 1000 pages, 500,000 words.

As a teaser, here is PDF of the book's Overview chapter, "On Memory Systems and Their Design". Clicking the link above will take you to the Morgan Kaufmann website.

-------- September 2007

And again -- fw00t! It's here.

Update: the book is now available and in stores. You can find it, for instance, on as well as at the publisher's site above. BTW, ignore the "Paperback" designation on the various websites describing the book ... it is hardcover, not softcover.

Contact Information

Prof. Bruce Jacob - email address -

Traditional correspondence can be sent to

Prof. Bruce Jacob
Dept. of Electrical & Computer Engineering
University of Maryland
College Park, MD 20742

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