Filesystem Implemenatation
CSC 213 - Operating Systems
Leah Perlmutter | Fall 2023
Announcements
Agenda for Today
Announcements
Q&A
P2P Chat Lab Q&A
Project Q&A
Can I use code from earlier in this class? yes! Includes labs, assignments, exercises, demos. Make sure to cite it.
Filesystems
Whiteboard:�Elements of a Filesystem
A Simple File System
disk
256 blocks, each 4KB�1 byte disk addresses��inodes
56 bytes of metadata�8 direct block pointers��layout
1 superblock�1 block for inode bitmap�1 block for data block bitmap�4 blocks for inode entries
What is the total size of this disk?�
How many inode entries or data blocks can be tracked with a single bitmap block?�
What is the size of an inode entry?�
How many inodes does this file system support?�
How many data blocks does this file system have?�
What is the largest supported file size?�
A (Slightly) Better Simple File System
disk
256 blocks, each 4KB�1 byte disk addresses��inodes
56 bytes of metadata�7 direct block pointers�1 indirect block pointer��layout
1 superblock�1 block for inode bitmap�1 block for data block bitmap�4 blocks for inode entries
Consider the same filesystem we looked at earlier, but now each inode entry contains an additional pointer to an indirect block.
What is the effect of adding this indirect block pointer?
What is the new max file size with this filesystem?�
here is the actual calculation
but if we weren't limited by disc size and pointer size...
(from earlier)
Wrap up
Announcements