[Ibin-Huan]

" Note that the configuration around a chiral atom (in R,S or D,L notation) does not define the direction in which polarized light will be rotated. In other words, a D configuration does not necessarily correlate with d (or +) rotation of polarized light". 
e.g L-(+) tartaric acid, is L means levorotatary if so why it is + not -
some compounds in nomancluture written d and some D , what is the different   

[Schrödinger]

d and l refer to the direction in which the plane polarized light is being rotated. (dextrorotatory and laevorotatory)

L and D refer to something else. They have to do with the parent compound from which the molecule was prepared.

[Dan]

They have to do with the parent compound from which the molecule was prepared.

This is not true. D and L are descriptors used in what is known as the Fischer-Rosanoff system.

See: http://www.chem.qmul.ac.uk/iupac/stereo/FM.html#03

Compounds are assigned D or L according to the direction in which the substituent at the last (possibly only) stereogenic centre points when the compound is drawn in a Fischer projection. If the substituent points right it is D, left it is L. The convention was originally applied to glyceraldehyde.

Sugars are named D or L by carrying through the D/L assignment from an hypothetical chain extension of D or L glyceraldehyde. e.g. D-glucose comes from a hypothetical chain extension of D-glyceraldehyde (but is not necessarily prepared from glyceraldehyde).

Just as R and S do not indicate the + or -, neither do D or L (except for glyceraldehyde).

[fledarmus]

And just in case the point didn't get across, there is a difference between lower-case d and upper-case D, and lower-case l and upper-case L. The lower-case d and l do correspond to dextrorotatory and levorotatory, which is (+) and (-) rotation of plane polarized light. Upper-case D and L correspond to the Fischer-Rosanoff system of notation described by Dan.

[Schrödinger]

I'm REALLY sorry, but hypothetical chain extension was what I wanted to say. That's what I meant...