April 27 through May 2

For Lecture, Monday, April 29

In preparation, read Tanenbaum, chapter 11, section 4. This section covers transactions, which we will study in detail in this week. Read the section with care.

For Recitation, Tuesday, April 30

Read "The recovery manager of the system R database manager" by Gray et al., reading #37. This paper is another heavy duty paper, but contains important information, which is well explained. Read this paper with care. Since it is such an important paper, there will be a reading report due (sorry!). Here is the question:

The System R database manager performs recovery using a checkpointed version of the database and a log of changes since the checkpoint. The paper says that one way to simplify recovery would be to only perform checkpoints during a "transaction-consistent state." (See p234.) First describe what this means, and how it is different from the approach that is actually used. Then explain the advantages and the disadvantages of using this simplified approach.

For Lecture, Wednesday, May 1

Read the Cirrus banking paper, reading #38, "The Cirrus banking network" by Gifford and Spector. This case study is shorter than the other two; you can skim it instead of giving it a detailed read. Also finish your design project, which is due in tomorrow's recitation section.

For Recitation, Thursday, May 2

Since your team's paper is due today, we moved the heavy-duty paper (reading #43) to next week. Instead you should read for today "The TWA reservation system" by Gifford and Spector, reading #39, and "When professional standards are lax: the CONFIRM failure and its lessons" by Oz, reading #40. Skim both papers, a detailed read is not necessary.

The following question was asked last year: Consider transaction processing in the TWA reservation system (reading #39). What framework is in place to support recovery from a crash? To mediate concurrent access to data? In terms of managing complexity, what benefits might TWA gain from using an approach like that of System R (reading #37)

Your team's report on design project 2 is due today in section.


System aphorism of the week
Een schip op het strand is een baken in zee.
(A ship on the beach is a lighthouse on the sea.) (Dutch proverb)

6.033 Handout 30, issued 4/25/96