QuoteRef: mckuMK8_1984

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ACM references m-z
references m-o
examples of file systems
immutable files and data
file system reliability
replicated data
file system
disk allocation
defensive programming
file input/output
virtual memory


McKusick, M.K. , Joy, W.N. , Leffler, S.J. , Fabry, R.S. , "A fast file system for UNIX ", ACM Transactions on Computer Systems, 2, 3, pp. 181-197, August 1984. Google

181 ;;Quote: description of new file system for UNIX 4.2bsd
184 ;;Quote: UNIX file system described by a replicated, immutable superblock
184 ;;Quote: UNIX uses at least 4K file blocks; allows 4 gigabyte files with two levels of indirection
184 ;;Quote: UNIX partitions disks into cylinder groups with copy of superblock, local inodes, free block bit map, and usage statistics
184 ;;Quote: a UNIX cylinder group preallocates an inode for every 2K bytes of disk; far more than needed
184 ;;Quote: bookkeeping information for a UNIX cylinder group is staggered to prevent a lost platter from destroying everything
185 ;;Quote: UNIX file as zero or more data blocks plus fragmented blocks; e.g., 1K fragments of 4K data blocks
185 ;;Quote: free disk bit map for UNIX at fragment level, but blocks are aligned
185+;;Quote: smallest UNIX fragment is a disk sector; need about 5% free disk space
186 ;;Quote: files should be extended one block at a time, with fragment at end; UNIX tells applications the optimal read/write size
188 ;;Quote: UNIX file system allocation accounts for block interleave; divides cylinder group into 8 rotational groups
189 ;;Quote: UNIX directories on different cylinder groups; inodes in a directory in the same group; at most 16 disk transfers for inodes of cylinder group
189 ;;Quote: large UNIX files spread across cylinder groups by new group at 48K bytes and every megabyte
190 ;;Quote: overflow UNIX allocation by rotational closest in cylinder, in same group, rehash to another group, exhaustive search
192 ;;Quote: about 40% of I/O time in UNIX is copying between system and user buffers
192+;;Quote: UNIX does not remap user buffers for I/O since requires page alignment and data would disappear after a write

Related Topics up

ThesaHelp: ACM references m-z (280 items)
ThesaHelp: references m-o (268 items)
Topic: examples of file systems (44 items)
Topic: immutable files and data (57 items)
Topic: file system reliability (26 items)
Topic: replicated data (45 items)
Group: file system   (9 topics, 285 quotes)
Topic: disk allocation (32 items)
Topic: defensive programming (22 items)
Topic: efficiency (96 items)
Topic: file input/output (21 items)
Topic: virtual memory (32 items)

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