PPT-The Coda File System

Jeff Chheng Jun Du Distributed file system Designed for scalability security and high availability Descendant of version 2 of Andrew File System AFS so follows same organization Virtue . C al Coda Play percussion on guitar while chord sustains brPage 2br 25 6fr 6fr 5fr 57371 6fr 6fr 6fr 5fr 4fr 29 33 5fr 5fr 4fr 4fr 37 3fr 41 45 ritenuto (Constant Data Availability). --Jay N. Vyas & Naveen Mohan--. Background. CODA is what? . – A Distributed File System (DFS). Developed by? . – Mahadev Satyanarayanan. Where & Why? . – At Carnegie Mellon University as a Research Project in 1987. 1Unix to be compatible with most applications, yet is highly scalable. Processes sharing a file at a single site seeexact Unix semantics. Processes at different sites see modifications at the granul File Concept. Contiguous logical address space. Types: . Data. numeric. character. binary. Program. File Structure. None - sequence of words, bytes. Simple record structure. Lines . Fixed length. Variable length. James J. . Kistler. and M. . Satyanarayanan. Carnegie Mellon University. Presented . by Cong. Content. I Motivation. II Coda Overview. III Implementation. IV Evaluation. V Conclusion. I Motivation. systems. L-. 20. More DFS. Andrew File System. Let’s start with a familiar example: andrew. 10,000s. of . machines. 10,000s. of . people. Goal: . Have a consistent namespace for files across computers. Advanced Operating System. Zhuoli. Lin. Professor Zhang. Outline. Semantics of File Sharing. File Locking. Sharing File in Coda. Future Work. Semantics of File Sharing. When two or more users share the same file at the same time, it is necessary to define the semantics of reading and writing precisely to avoid problems.. Clocks. External clock synchronization (. Cristian. ). Internal clock synchronization (. Gusella. & . Zatti. ). Network Time Protocol (Mills). Decisions. Agreement protocols (Fischer). Data. Distributed file . Outline. Overview of file systems. File system design. Sharing files. Unix file system. Consistency and crash recovery. Journaling file systems. Log-structured file . systems. 2. Review. We saw that file systems use write-back caching for improving the performance of file writes. 1. File Concept. Contiguous logical address space. Types: . Data. numeric. character. binary. Program. CS 3100 File-System Interface. 2. File Structure. None - sequence of words, bytes. Simple record structure. ). . The permissible . phonotactic. rules that are associated with the coda of the syllable are:. A case of a zero coda is possible in English, as in . two. /. tu. :/, . so. /. s∂ʊ. /, etc. (Roach, 2002: 15).. sees VLeZBo[: ,nteJratLnJ LocaO FLOe S\stems Yupu =KanJ CKrLs DraJJa Andrea ArpacL-Dusseau RemzL ArpacL-D Incredibly popular: Dropbox has 100 million+ usersBack up files to th





















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Interface. File Concept. Access Methods. Directory Structure. Allocation Methods. Objectives. To explain the function of file systems. To describe the interfaces to file systems. To discuss file-system design tradeoffs, including access methods, file sharing, file locking, and directory structures.