EP0284664A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method of rapidly opening disc files identified by path names
Assignee: International Business Machines Corp
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Filing: 1987-12-15
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Granted: —
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Expires: 2007-12-15
Abstract
Abstract A data processing system has files stored on disks in a tree structure of directories and files. The system is operated to rapidly open files which have been recently opened or for which partial path information is available, by accessing a drive cache (30) in main memory (16). The cache has entries chained in a tree structure which is then searched to provide the same information during the opening process as that information which would otherwise have to be obtained from a disk (22). When the cache is full, a new entry replaces the least recently used entry.
Inventors
- 👤 Kenneth Walter Christopher Jr.
- 👤 Barry Alan Feigenbaum
- 👤 Jin Kim
- 👤 Douglas Carleton Love
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 13:51
CPC Classifications
G; G06; G06F; G06F12/00; G06F12/02; G06F12/08; G06F12/0802; G06F12/0866; G06F16/00; G06F16/90; G06F16/901; G06F16/9017; G06F16/902; Y; Y10; Y10S; Y10S707/00; Y10S707/99931
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
138 words
A method of operating a data processing system to open a recently opened but now closed file contained on a disk and located in a tree structure of directories and files, characterised by the steps of: creating a cache in main memory of said data processing system when said file is initially opened, containing a plurality of chained entries identifying said file and each directory contained in said tree structure which lies in the path to such file, said entry for said file containing information read from said disk and identifying said file and where it is located on said disk; and in response to a subsequent request to open said file, searching through said chained entries in said cache and accessing said information thereby avoiding having to obtain the same information by reading it from said disk.
Claim 2
Independent Claim
138 words
A method of operating a data processing system to open a recently opened but now closed file contained on a disk and located in a tree structure of directories and files, characterised by the steps of: creating a cache in main memory of said data processing system when said file is initially opened, containing a plurality of chained entries identifying said file and each directory contained in said tree structure which lies in the path to such file, said entry for said file containing information read from said disk and identifying said file and where it is located on said disk; and in response to a subsequent request to open said file, searching through said chained entries in said cache and accessing said information thereby avoiding having to obtain the same information by reading it from said disk.
Claim 3
Dependent Claim
73 words
A method according to claim 1, wherein said data processing system has plural disk drives, including the step of: creating plural caches corresponding in number to the number of disk drives and including in each cache a drive header identifying each drive; and in which said searching step comprises first accessing at least one drive header to locate the one of said caches corresponding to the drive containing the file to be opened.
Claim 4
Dependent Claim
74 words
A method according to claim 1 or claim 2, in which said creating step includes providing a cache of a size for containing a predetermined number of entries; and including the further steps of: initially filling said cache by placing entries therein in unused locations; and thereafter adding new entries by placing each one in a location corresponding to which existing entry in said cache corresponds to that of the least recently used file.
Claim 5
Independent Claim
37 words
A method according to any of the previous claims, including the step of: storing pointers in said entries to create a chain of entries ordered from the most recently used file to the least recently used file.
Claim 6
Independent Claim
60 words
A method according to any of the previous claims including the step of: opening a file for which existing entries in said cache form part of a complete path to such file, by accessing those entries in said cache corresponding to such part and then reading such further information as is necessary to form a complete path, from said disk.
Claim 7
Dependent Claim
23 words
A method according to claim 5, including the step of: creating entries from such further information and adding such entries to said cache.
References Cited (Backward Citations)
No citation records indexed.
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