| OCR Text |
Show 14 exclu sion is supported by stor ing objects in a vo latile pool and givmg a client c'xr lii sive access to those objects . Not ifi cat ion has two aspects : register ing in terest Ill part icular <~vents and receiving not i r:r~s of the events as they OCClir. Fo 1· It~c u v<-T y , fVIIl< ~ J lW s tcm~s lug iurormation pc~ rt a iui ng to a part icular segment of data in the segment itself. 2.5 .6 02 02 [22] was developed by the Altair research consort ium, consist ing of INFUA, Sicc' JlJ C' Il S- Nixclorf, Bull, t he CNRS, and the University of Paris Xl.lt is an OODBMS vv it J, a complete developm ent environm ent a. ncl a. set of Ji ser inte rface tool s. It has la nguage in terfaces to C and C++. 02 uses WiSS (Wisconsin Storage System) [8] as its storage manager. WiSS f>ruvid es record struct ured sequ ent ial Illes . The WiSS record identifier (RID) has a vo luiiW id e ntifi er (2 bytes), a page ideuLi lier (4 bytes), and a slot number (2 by tes). IU J) s a re used rts prrsistent id entifiers for obje~cts. 'vVhen records n1ove on disk, liwl' k <IVl' <I fonv<J rcli ng 1{11) al t lwi1 ori giJJ <ll locatio JJ. 01 d.llows IJS<Ts to de fine cl11 ster trf~es to cl es crille cltt ster ing policie~s for collections of objects. lt supports B-tree and hash-code indi ces on obj ects. Recovery in 02 is "log" based . Concurrency is handl ed with a hierarchi ca.l. tw u~ f>hasc locking protoco l whi ch is coord inated hy a glo bal lo ck m<tn age r at the se rver and local Inanagers at the client sites . T he cli ent and server in te ract in terms uf" pages . T li c:sc pages are cac hed at the server site as well as cLient site and the cli t~ JJ t performs 1110:-d, of t he object-related work. 2.5.7 ObServer ObServer [1] was de ve loped at Brown Uni ve rsity. It is a general purpose obj ect S (-'J \'(·' 1" . It provides secondary storage or <t.rhi t rarily s ized ohj ec:ts Cor datct.base iJaJJS<lc-tions and faci li tdtrs cooprrati on betw cc~c n these transaction s. |
