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Stub file

About: Stub file is a research topic. Over the lifetime, 9883 publications have been published within this topic receiving 251606 citations.


Papers
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Journal ArticleDOI
TL;DR: In this paper, a log-structured file system called Sprite LFS is proposed, which uses a segment cleaner to compress the live information from heavily fragmented segments in order to speed up file writing and crash recovery.
Abstract: This paper presents a new technique for disk storage management called a log-structured file system. A log-structured file system writes all modifications to disk sequentially in a log-like structure, thereby speeding up both file writing and crash recovery. The log is the only structure on disk; it contains indexing information so that files can be read back from the log efficiently. In order to maintain large free areas on disk for fast writing, we divide the log intosegmentsand use a segment cleaner to compress the live information from heavily fragmented segments. We present a series of simulations that demonstrate the efficiency of a simple cleaning policy based on cost and benefit. We have implemented a prototype log-structured file system called Sprite LFS; it outperforms current Unix file systems by an order of magnitude for small-file writes while matching or exceeding Unix performance for reads and large writes. Even when the overhead for cleaning is included, Sprite LFS can use 70% of the disk bandwidth for writing, whereas Unix file systems typically can use only 5–10%.

2,403 citations

Book
31 Dec 1994
TL;DR: A prototype log-structured file system called Sprite LFS is implemented; it outperforms current Unix file systems by an order of magnitude for small-file writes while matching or exceeding Unix performance for reads and large writes.
Abstract: This paper presents a new technique for disk storage management called a log-structured file system. A log-structured file system writes all modifications to disk sequentially in a log-like structure, thereby speeding up both file writing and crash recovery. The log is the only structure on disk; it contains indexing information so that files can be read back from the log efficiently. In order to maintain large free areas on disk for fast writing, we divide the log into segments and use a segment cleaner to compress the live information from heavily fragmented segments. We present a series of simulations that demonstrate the efficiency of a simple cleaning policy based on cost and benefit. We have implemented a prototype log-structured file system called Sprite LFS; it outperforms current Unix file systems by an order of magnitude for small-file writes while matching or exceeding Unix performance for reads and large writes. Even when the overhead for cleaning is included, Sprite LFS can use 70% of the disk bandwidth for writing, whereas Unix file systems typically can use only 5--10%.

1,312 citations

Journal ArticleDOI
TL;DR: This work discusses in detail the design decisions that led to the grid file, present simulation results of its behavior, and compare it to other multikey access file structures.
Abstract: Traditional file structures that provide multikey access to records, for example, inverted files, are extensions of file structures originally designed for single-key access. They manifest various deficiencies in particular for multikey access to highly dynamic files. We study the dynamic aspects of file structures that treat all keys symmetrically, that is, file structures which avoid the distinction between primary and secondary keys. We start from a bitmap approach and treat the problem of file design as one of data compression of a large sparse matrix. This leads to the notions of a grid partition of the search space and of a grid directory, which are the keys to a dynamic file structure called the grid file. This file system adapts gracefully to its contents under insertions and deletions, and thus achieves an upper bound of two disk accesses for single record retrieval; it also handles range queries and partially specified queries efficiently. We discuss in detail the design decisions that led to the grid file, present simulation results of its behavior, and compare it to other multikey access file structures.

1,222 citations

Patent
04 Apr 2003
TL;DR: In this paper, the authors propose to add file attachments and non-database objects, such as, text file data, web file data and image file data to databases, at the convenience of a node to which the objects are sent.
Abstract: Attaching files and other objects in a distributed computing environment. This includes adding file attachments and non-database objects, such as, text file data, web file data, image file data, and other file attachment objects to databases. These objects may be retrieved at the convenience of a node to which the objects are sent. Visibility rules can be set to determine which attachments and objects are seen by a node. Distribution rules for an object determine whether a node must request the object or whether the node is forced to receive the object.

1,197 citations

Journal ArticleDOI
TL;DR: The nature and implementation of the file system and of the user command interface are discussed, including the ability to initiate asynchronous processes and over 100 subsystems including a dozen languages.
Abstract: UNIX is a general-purpose, multi-user, interactive operating system for the Digital Equipment Corporation PDP-11/40 and 11/45 computers. It offers a number of features seldom found even in a larger operating systems, including: (1) a hierarchical file system incorporating demountable volumes; (2) compatible file, device, and inter-process I/O; (3) the ability to initiate asynchronous processes; (4) system command language selectable on a per-user basis; and (5) over 100 subsystems including a dozen languages. This paper discusses the nature and implementation of the file system and of the user command interface.

1,140 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20226
20211
20202
20197
20189
2017105