| OCR Text |
Show lE9 the exte5ive overhea of tack cinter5 (e.S'. i a tribe poier fie1), since he otject can cickly = searced for references attribute. to a c ar t i c c l e r As a contrast, consider the VD structure used to ilerre Geeral otorts APL sys:err (see sectio 3. and [12]). E!eca'..:se pc l yb e c r e , faces, e c c e s , and po i n t s are all inc5epedent entities in a large file, the systerr. ust maintain a great deal more linkage inforrr.ation i order to access these structures quickly. VDAM maintains auxilary pointer arrays for bot owner sets and meber sets. 7.1 shows the details of ho an edge and its two encpoints :-i<;\,,1re 7.2 . c ,,' 2 : ; e c c r res? c n C ins 0 o j e c t; IT I) del r e c res e n t e t i 0 • ties as any pointers necessary in VDAM. Furtherr.1cre, sice t2e pointers are cfsets i a large f;'o te cre than 16 tits long. ile the exact details of the VD! irrpelentation are not kncn to the author, it is clear that te cject oc5e1 implementation is both siropler and short2r. Tis is ossible tecause attributes are contained inc l: j .= c : 5 • r:: l. e c b j e c t p r c> v i d e s are l a t i v ely 5 IT. a 11 It spa celt hic cc:ain5 only theSE attritutes which belong to the o:.ject. |
