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Memo Enhancement
Message
De
21/05/2003 16:00:18
Hilmar Zonneveld
Independent Consultant
Cochabamba, Bolivie
 
 
À
21/05/2003 15:37:59
Information générale
Forum:
Visual FoxPro
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
Divers
Thread ID:
00790322
Message ID:
00791304
Vues:
29
>>When reading data, the operating system usually keeps some data in cache. WhenIn some cases, the operating system may also have a cache for writing - in other words, data is not immediately saved to disk. This is dangerous for data corruption. I don't know how to disable it - and it probably depends on the operating system. Perhaps somewhere in properties of the hard disk. I think Windows 98 doesn't have the option for a write cache, but Windows 2000 does - but I am not sure.
>
>Hilmar,
>
>A small 'tweak' to the explanation...
>Write cache is a hardware thing that, thankfully, can be turned off/on by software.
>When write cache is ON then the HD controller reports back a successful write as soon as it has cached the data in its OWN on-board cache. While it will write the actual data very soon thereafter a failure of the HD or a sudden power off will cause the data to be lost.
>With write cache turned OFF then the HD will only report that the data has been written when it has actually been written to the physical HD.
>
>cheers

Thanks. I also forgot to mention an alternative: use a UPS.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)
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