A crazy data backup scheme that works

So heres the cool and sexy part: Symform protects your data through a redundancy mechanism it calls RAID-96. First, your backup data is hacked into 64MB blocks. These blocks are then encrypted using the industry standard AES-256 encryption algorithm. They are further chopped into 64 blocks of 1MB each. From those 64 blocks, 32 more parity blocks are computed, allowing you to reconstitute the original 64 1MB blocks from any 64 of the 96 resulting blocks. From there, the 96 1MB blocks are shipped out to 96 other nodes in Symforms Cooperative Storage Cloud.

via A crazy data backup scheme that works.

hmmm. but wouldn’t you need something more? if your data are in the cloud you would need multiple, redundant network connections – that’s RAIN

Whitespace

Most modern programming languages do not consider white space characters (spaces, tabs and newlines) syntax, ignoring them, as if they weren’t there. We consider this to be a gross injustice to these perfectly friendly members of the character set. Should they be ignored, just because they are invisible? Whitespace is a language that seeks to redress the balance. Any non whitespace characters are ignored; only spaces, tabs and newlines are considered syntax.

via Whitespace.

Linked list – Google Patent Search

A computerized list is provided with auxiliary pointers for traversing the list in different sequences. One or more auxiliary pointers enable a fast, sequential traversal of the list with a minimum of computational time. Such lists may be used in any application where lists may be reordered for…

Inventor: Ming-Jen Wang

Assignee: LSI Logic Corporation

Primary Examiner: John Breene

Secondary Examiner: Cheryl Lewis

via Linked list – Google Patent Search.

Do I have to pay royalties for my homework in 1979?

Extreme Polyhierarchy

Compared to the physical world, one of the online world’s benefits is that items can live in multiple locations. Because websites can classify products and other content along multiple dimensions, they help users navigate locally to related items and provide faceted winnowing of a large product space into manageable shortlists that can satisfy the user’s main requirements.

via Top-10 Information Architecture (IA) Mistakes (Jakob Nielsen’s Alertbox).

RENAME table

From Ian Smith, Rdb Engineering

RENAME TABLE renames the metadata but leaves the old name as a synonym so that triggers, constraints, stored procedures, default, computed by, automatic as, views, etc continue to run. This synonym is required, and should only be deleted if you know there are no dependencies (the simplest of tables). So this is probably not the tool for you.

Instead I’d suggest defining a synonym for use by applications and other definitions. Then you can switch the synonym from one table to the other as required. This scheme works better than views because there is no metadata lock on the synonym name.

How to Kill Your Book Sales

How to Kill Your Book Sales | Carsten’s Random Ramblings

I believe the first time I heard about using publically-available Flightstats database for teaching databases was when Jeremy Cole suggested using it in the MySQL training program to demonstrate working with large data sets. I’m not sure it ever got used for that purpose, but others have followed up on the same idea in other contexts. The Flightstats database contains 10 years of US airline flight information, consisting of several Gigabytes of data in a fairly wide table, and so is excellent for talking about optimizations and search strategies.

The article is about book sales, but it really talks about sample databases for demonstration purposes.

Natural, Artificial, Exposed and Surrogate Keys Explained

IntelligentEnterprise : Celko on SQL: Natural, Artificial, Exposed and Surrogate Keys Explained (printable version)

By Joe Celko

There is no such thing as a “universal, one-size-fits-all” key. Just as no two sets of entities are the same, the attributes that make them unique have to be found in the reality of the data. You can decide on the kind of key you want to use based on the nature of your particular situation.