Adam object size - questions

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Product: Aleph
Product Version: 20, 21, 22, 23
Relevant for Installation Type: Dedicated-Direct, Direct, Local, Total Care

Question
Are there limits in ADAM regarding the size of single objects? Are there any technical objections when saving huge objects? Should objects better be linked with field 856u rather then saving them on the Aleph server?

Answer
From aleph side there are no restrictions regarding the file or directory size. The only limits are set by the operation system or according to the the hardware. With older hardware there was a general limit of 2GB but this should not be a problem with newer systems. See also http://en.wikipedia.org/wiki/Compari...systems#Limits. Clarify with your Unix system administrator if your system has any limits.

There are however limits regarding the Aleph indexing:
a) A single catalog field can have 2000 characters
b) Only 5000 fields per record are indexed. All fields all counted, also virtual fields that are expanded from other records, e.g. items or ADAM objects.
c) For each record only 4950 words (before Aleph 22) or 20000 words (Aleph 22 and up) are considered in the WORD indexing.
This limits are not valid for TXT index in ADAM but for expanded indexes WTX and WRD.

So if a PDF has 100MB and has lots of text there could be a problem. If the document has graphics or drawings which have not to be indexed there will be no problem.

Please note that ADAM was not designed for managing large full texts but for table of contents, title pages etc. For larger objects Digitool or Rosetta would be the right programs.

It doesn't matter whether a PDF is stored locally on the Aleph server or only linked in field 856. The only benefit of linking via 856 field is that Aleph disc space is stored. Also this should be clarified with the system administrator.

Article last edited: 15-May-2016