Missing or corrupt drawing or data.

We have a number of reports of missing or corrupt drawings or data. The common factor is that the drawing was filed in one session, apparently without error, but could not be found (missing) or had errors (corrupt) in the next session. A secondary, but related, report concerns drawings that are visible in the pictorial index (and in fact perfectly OK) but lack an active 'handle' to use for loading or inserting the drawing.

Often these are the result of user error. One common cause is deleting the drawings (using Windows Explorer, or similar) because the user did not realize what they were. This is especially true when more than one user has access to the computer, or when programs other than Accucadd store data in an Accucadd library. Accucadd drawing data is stored in files with the extensions RLF and SNP; typical names might be 10100000.RLF and 10100000.SNP.

Also, all drawings are grouped in index folders (IDX00000 through IDX65537) which in turn are contained in the library folder. We recommend the library folder be called LIB to aid in identifying it to all users.

The golden rule, then, is that you never use any program other than Accucadd to store, retrieve, or alter any files within the Accucadd library folder. Ignore this at your peril!

After all these user problems have been taken into account, there remain a few more cases. What causes these? Some insight into the problem may be had from the following note, taken from Microsoft's web site  http://windowsupdate.microsoft.com/ 

"The Windows IDE Hard Drive Cache Package provides a workaround for computers running Windows Millennium with Integrated Drive Electronics (IDE) hard drives, large caches, and modern processors. IDE hard drives store data in a hardware cache (temporary memory) and write the data to the hard disk later. For these computers, data can be lost during the shutdown process because the amount of time that it takes for fast processors to shut down is so short that the hard disk may shut down before the data in the cache is written to the hard drive. This update introduces a two second delay in the shutdown process, which allows the hard drive's cache to write any data to the hard drive. Download now to delay your shutdown process slightly to prevent data loss."

We suggest you review this material, Windows IDE Hard Drive Cache Package, and consider the advisability of applying the patch to your system. Microsoft says its size is 223 KB and the typical download time is < 1 min. Also take look at this Technical Bulletin.

Also, if you search this site for "disk cache windows" you will find quite a few articles relating to data loss and/or corruption with various versions of Windows - again, we suggest you review these and consider your strategy.