Some IMDBs allow the database schema to specify different durability requirements for selected areas of the database-thus, faster-changing data that can easily be regenerated or that has no meaning after a system shut-down would not need to be journaled for durability ( though it would have to be replicated for high availability ), whereas configuration information would be flagged as needing preservation.
32.
The other major feature introduced in version 2.0 was an enhanced version of the Journaled File System which allowed the operating system to be booted directly from JFS-formatted partitions . ( Previous versions of JFS had only been usable on non-bootable data partitions . ) Installing the operating system onto JFS allowed a significant performance improvement, due to the much larger cache sizes supported by JFS, as well as reduced CHKDSK times in the event of a non-clean shutdown.
33.
If there is a power outage or kernel panic while a file is being written or appended to, the journal will indicate that the new file or appended data has not been " committed ", so it will be purged by the cleanup process . ( Thus appends and new files have the same level of integrity protection as the " journaled " level . ) However, files being " overwritten " can be corrupted because the original version of the file is not stored.
34.
The guide rail was a simple stringer of yellow pine, 4?by 8 inches in section, and the standards on which the wheels are journaled were placed far enough apart to allow a space of 6 inches between the continuous faces of each pair of wheels, thus affording 1?inches for lateral play, or sidewise movement toward or from the guard rail, it being designed that the guide rail shall be arranged in the exact line of the true center of gravity of the cars and locomotive.
35.
Quoted directly from the Snakeboard patent Abstract and Claims : " This invention relates to a skateboard comprising two footboards each of the footboards including a foot platform and wheel-set which carries two wheels in axial alignment fixed to the underside of the platform, a spacer element for holding the footboards in a spaced relationship and a pivot arrangement having a vertical pivot axis connecting each footboard to the spacer element to enable both footboards to pivot relatively to the spacer element, each wheel set including a wheel body, wheel axles which are fixed to and project from the opposite sides of the body with the wheels being journaled for rotation on the axles, a first pivot pin being attached to the wheel body with its axis in a vertical direction, a support member on the wheel body, a second pivot pin pivotally connecting the foot platform to the support member with its pivot axis normal to the wheel axis, and resilient suspension means between the support member and the underside of the foot platform for holding the platform horizontal, said pivot arrangement being pivotally engaged with the first pivot pin ."
