COS/PSA 413. Day 4. Agenda. Questions? Assignment 1 Corrected 3 A’s, 2 B’s, 2 C’s, 2 D’s and 1 F’s Assignment 2 posted Due in one week Lab Write-ups (project 2-1 and 2-2) due Lab tomorrow at OMS Project 2-5, Project 3-3, Project 3-4 (with modifications), Project 3-6
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Hierarchical File System – The system used by the MAC OS to store files, consisting of folders and subfolders, which can be nested.
File Manager – In Macintosh file system, it handles the reading, writing, and storage of data to physical media. It also collects data to maintain the HFS along with manipulation of files, folders, and volumes.
Finder – Works with the Macintosh OS to keep track of files and maintain the user’s desktop.
Data Fork – The part of the Macintosh file structure that contains the actual data of a file.
Resource Fork – The part of the Macintosh file system that contains the resource map, header information for the file, window locations, and icons.
Volume – Refers to any storage media in the Macintosh file system. A volume can be a single floppy disk, a partition on a hard drive, the entire drive, or several drives.
Allocation Blocks – The number of logical blocks assembled in the Macintosh file system when a file is saved.
Logical Blocks – In the Macintosh file system, a collection of data that cannot exceed 512 bytes. These are assembled in allocation blocks to store files.
Logical EOF – In the Macintosh file system, the number of bytes that contain data.
Physical EOF – In the Macintosh file system, the number of allocation blocks assigned to the file.
Difference between the two is free space
Clumps – In the Macintosh file system, a contiguous allocation block. Clumps are used to keep file fragmentation to a minimum.
Master Directory Block (MDB) – On older Macintosh systems, the location where all information about a volume is stored. A copy of the MDB is kept in the next to the last block on the volume.
Volume Information Block (VIB) – Another name for the Master Directory Block.
Extents Overflow File – Used by the Macintosh File Manager when the list of contiguous blocks of a file becomes too long. The overflow of the list is placed in the extents overflow file. Any file extents not in the MDB or VCB are contained here.
Volume Control Block (VCB) – Contains information from the MDB and is used by the File Manager in the Macintosh file system.
Catalog –Is used to maintain the relationships between files and directories on a volume.
Volume Bitmap – Tracks each block on a volume.
B*-Tree –Organizes the directory hierarchy and file block mapping for the File Manager.
Header Node – Stores information about the B*-Tree file.