General OS/NDS/DB quals notes
Ed Swierk
2002


Design tradeoffs (from CS 245)

flexibility   vs  space utilization

    vs                   vs

complexity    vs     performance


Paging strategies for DBMS vs OS

LRU is usually best for OSes
May not be ideal for a DB, e.g. when doing a scan, the last
element read is probably not going to be accessed again soon.


Two functions of an OS (Tanenbaum 1.1)

extended machine (top-down view): extends, abstracts, virtualizes the
interface presented by the hardware to make it easier to program

resource manager (bottom-up view): orders and controls allocation of
the pieces of the system among the various programs competing for them


OS ontogeny recapitulates phylogeny


Replication for fault tolerance: useful for dealing with hardware
faults (CPUs, buses, I/O devices), and for nondeterministic software
faults (i.e. running the same program with the same inputs doesn't
produce the same faulty result); not useful for general software
faults (fault containment is the best you can do here).