軟件體系結(jié)構(gòu)信息共享體系結(jié)構(gòu)sharedinformation-文庫(kù)吧資料
2024-10-06 09:31本頁(yè)面
【正文】 re ? Global database containing entire state of problem solution 全局?jǐn)?shù)據(jù)庫(kù)包含解域的全部狀態(tài) ? Only means by which knowledge sources interact 知識(shí)源互相作用的唯一媒介 ? Control ? Knowledge sources respond ? “opportunistically” 讓知識(shí)源響應(yīng)偶然事件 169。 28 2020/11/4 Varieties of Repositories Discriminate on control strategy（在控制策略上的區(qū)別） ? Predetermined by designer （設(shè)計(jì)者預(yù)先定義好） ? Compilers ? Driven by types of information in input stream 輸入流的信息類型決定 ? Database transaction system ? Driven by availability of new information from other parts of the system （系統(tǒng)其他部分的新信息決定） ? Scratchboard （刮板） ? Opportunistic: driven by state of putation 機(jī)會(huì)主義：計(jì)算的狀態(tài)決定 ? Blackboard 169。 26 2020/11/4 Software Tools with Shared Representation 169。 24 2020/11/4 Example: Modern Canonical Compiler 169。 22 2020/11/4 CASE vs. DBMS ? As pared to databases, CASE has: ? more types of data 更多的數(shù)據(jù)類型 ? fewer instances of each type 更少的數(shù)據(jù)類型實(shí)例 ? slower query rates 更慢的查詢頻率 ? larger, more plex, less discrete information 更大，更復(fù)雜，更集中的信息 ? but not shorter lifetime 生命周期沒(méi)有更短 169。 ? “ Layered” hierarchy 層次風(fēng)格 169。 passive mappings don?t suffice。 ? Repository model with external control （倉(cāng)庫(kù)風(fēng)格） Problem: information became distributed among many different DBs. 新問(wèn)題：信息分布到很多不同的數(shù)據(jù)庫(kù) 169。 18 2020/11/4 Multidatabases 169。 17 2020/11/4 Unified Schemas for Integrating Databases Abstraction: multiplex the databases。 15 2020/11/4 Evolution of Shared Information Systems ? Datapool (Shared Memory) Example: ? Enabled by availability of RAM and languages to permit the sharing of mon data (., FORTRAN COMMON BLOCK) ? Processes are not necessarily sequential ? Gets messy without implementation rules what are the issues? 169。 13 2020/11/4 Early File Access ? In the earliest systems, code had to be written to position the media, read the data, and do any associated “house cleaning” operations. 早期的系統(tǒng)，很難編寫代碼來(lái)完成定位存儲(chǔ)介質(zhì)、讀數(shù)據(jù)等操作 169。 11 2020/11/4 Shared Information Systems Lineage ? Today ? shared information systems appear everywhere from the smallest business, to the most advanced scientific applications 從最小的商業(yè)應(yīng)用到最頂尖的科學(xué)應(yīng)用，信息共享無(wú)處不在 ? many applications
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