xml-dev - Re: Healthcare and Security/Privacy

[Jack Rusher <jar@integratus.com>]

"K. Ari Krupnikov" wrote:
> 
> Add to this transactional integrity, referential intergrity and caching
> that most RDBMSs (with the notable exception of MySQL, which in some
> ppl's oppinion is an SQL wrapper around a filesystem) provide for free.

  Transactional support?  Journaling with rollback.
  Referential integrity?  Dirty region logging.
  Caching?  Buffer/vnode caching?

  These things are available today in VxFS (for example).  There are
a lot of modern filesystems that owe more of their structure to the
Stonebraker paper on The Design of the Postgres Storage System than
they do to Maurice Bach's description of the Unix File System.

  There are a number of file oriented storage systems that provide
anything from BASE to ACID semantics for transactions.  There is an
extensive chapter in the famous Gray, et al, text on Transaction
Processing that addresses exactly these design issues.

  There have also been a number of file systems built on top of OS
database services (see ErosOS, etc) over the years.  The world does
not start and end with UFS and FAT32.  There are other technologies;
work has been done.

  In any case, none of this is provided "for free."  There are, as
always, assorted design trade offs inherent in building any sort of
storage subsystem.  If you implement a two phase commit transactional
model, there will be performance issues that need to be considered.

  This has the smell of a potential long term silly argument that
could pollute this otherwise sparse and high signal to noise ratio
mailing list.  I recommend that those who are interested in a more
fundamental understanding of the technologies underlying data storage
seek the above references.

Respectfully,

-- 
Jack Rusher, Senior Software Engineer | mailto:jar@integratus.com
Integratus, Inc.                      | http://www.integratus.com