Cris Pedregal Martin
Assistant Professor
Department of Computer Science
University of New Mexico

contact info (why?


Recovery in databases and beyond

My research aims to improve the conceptual tools to specify and reason about recovery, an essential but somewhat neglected component of transactional systems. The underlying thesis is that, in spite of superficial differences, a broad range of systems and application domains share similar recovery needs that are met by combining a small set of essential ingredients. My work characterizes those ingredients and uses them to expose the essential and incidental similarities and differences in recovery support across domains (e.g., databases, mobile systems, e-commerce).

While substantial research efforts into concurrency control have yielded a rich body of theory and practice, the more limited study of recovery has yielded mostly implementation-specific knowledge. There exist both high-level descriptions of recovery requirements (such as Failure Atomicity), and an important body of (low-level) knowledge on how to implement recovery; however, a unified model of recovery that explains and connects both levels is lacking. Thus explaining and specifying the properties of recovery and its interactions with other system components must be done in terms of specific implementations, at a low algorithmic and architectural level. Besides making design and implementation costly, this situation hampers the design of recovery in the context of novel applications, whose semantics and implementation tradeoffs differ from those of traditional transaction models. I believe that there is a need for a deeper understanding of the essentials, to better enable specifying and reasoning about recovery; my work is an attempt to address these issues. For more on this, see my papers page.

Computer-assisted instructional technology

I am a member of the MANIC project, whose goal is investigating how to most effectively use the Internet and off-the-shelf mass storage (e.g., CD/DVD-ROM) to deliver lectures and course materials outside of the classroom. Our focus is on asynchronous learning environments in which students proceed at their own pace and are not assumed to be accessing the same material at the same time. Students can access lectures as digital audio or video, synchronized with slides, overheads or other materials. Specifically, I am interested in developing server-side open-source technology to support delivery of instructional content. As an experiment, we designed and implemented DB-MANIC, a database-backed web service. DB-MANIC delivers content a la MANIC, in the form of slides and synchronous continuous media (e.g., audio). It has been used to support an introductory Neuroscience course at Smith College; further deployment is planned. See the SAINT'01 paper in my papers page.

Previous work

I have a longstanding interest in the role abstraction plays in Computer Science. My initial research on recovery arose out of the problems encountered when studying linguistic support for specifying and implementing extended transaction models for databases. This involves concurrency control, recovery, and programming languages, and, more broadly, the tension between abstraction and implementation. Recovery stood out as an essential part that was still not well-understood.

At Xerox PARC I participated in the design of a system for indexing and manipulating multimedia streams. I helped design a rich but simple multimedia model to support collaboration among intellectual workers. At the Distributed Object Computing Group (GTE Labs, now Verizon Labs) I investigated how to define and implement extended transactions on distributed object systems. Here at UMass I worked on implementing a real-time programming language based on a concurrent language. I investigated the problems of integrating concurrency in object-oriented programming languages for my graduation thesis (PDF, PS) at Eslai (Argentina).



  • my photographs (why?):
    mixed and by place
  • my visit to Bombay
  • all about photography,
    many pictures:
  • Texts & Ideas

  • the insidious decay of IT
    in Latin America
  • the iPic ... a wee tee cee pee
    stack and webserver.
  • W. Pratt and O. Shivers
    on grad school, the thesis
  • eclectic favorites 
  • some of my writing, coffee
    messages, on Internet myths

    Always under Construction, like Thekla (click)
      Cris, 2003.08.24