Hi Mats The 2 GB limit is a MapInfo limit and NOT an OS limit.
Even under Fat32 you can have files up to 4 GB and under NTFS you can have files up to 16 Terrabytes. MapInfo is limited in this way because they use a signed 32 bit long as a pointer to the Map File. I have created a new 64 bit file format and have tested this with full National Coverage of Great Britain. We have information on this at: http://www.GBplc.co.uk I have used this on FAT 32 and so can confirm the 4 GB limit. I have also tested up to 12 GB files under NTFS. I would need an even larger data set to go above this. I am working on a TAB to GZ convertor so if anyone has large datasets they would like to test keep an eye on GBplc.co.uk for the new free TAB to GML(compressed to GZ) as well as free GML(compressed to GZ) to BIG ( 64 bit format). Regards Bob @www.MapsByDesign.co.uk In message <[EMAIL PROTECTED] e.se>, Mats Elfström <[EMAIL PROTECTED]> writes >Hi Dave! > >I think your analysis is correct. >I believe the numbers are as follows: > >Max field length: 255 bytes >Max number of fields: 255 (as someone pointed out, if you need that >many, it's bad database design) >Max length of record: ~4000 bytes (quickly reached if you join in some >Access tables) >Max Tab file size: 2 GB (OS limit, not MapInfo) > >I have noted on some occasions that some data tables have very long >character fields, 255 bytes. >I believe this data to be of Access origin, and originally were memo >fields which have no limit length in Access. >As the DB structure of MI cannot handle memo fields they probably get the >max character field length when put into the MI DB format. >Imagine what will happen if you have a number of such fields, the 4000 >byte barrier is reached very quickly. > >Hälsning / Best regards Mats.E >________________________ >FB Engineering AB >Södra Förstadsgatan 26 >211 43 Malmö > >Tel: 040-660 25 50 >Mobil: 0705-27 60 27 >Fax: 040-660 25 99 >[EMAIL PROTECTED] >www.fbe.se > > > >"David Baker" <[EMAIL PROTECTED]> >Sänt av: [EMAIL PROTECTED] >2006-01-24 01:06 >Sänd svar till >[EMAIL PROTECTED] > > >Till >[email protected] >Kopia > >Ärende >RE: [MI-L] Number of fields > > > > > > >On 23 Jan 2006 at 22:27, Peter Horsbøll Møller <[EMAIL PROTECTED]> wrote: > >> As far as I remember there is a limit of 4000 bytes per record > >Ah, thank you Sir - you've probably just solved a long-standing problem >I've had. I have >a Microsoft Access table with only 56 fields that I call from MapInfo, but >found that I got >strange errors when adding a new field. I can't remember the actual error >message, >but it wasn't anything logical to me, and took ages to figure out that it >was caused by >this extra field being added. So, I went without the field, knowing that I >hadn't reached >the 255 field limit, but must have bumped into some other limitation. > >Dave >_______________________________________________ >MapInfo-L mailing list >[email protected] >http://www.directionsmag.com/mailman/listinfo/mapinfo-l > >_______________________________________________ >MapInfo-L mailing list >[email protected] >http://www.directionsmag.com/mailman/listinfo/mapinfo-l -- bob young _______________________________________________ MapInfo-L mailing list [email protected] http://www.directionsmag.com/mailman/listinfo/mapinfo-l
