mirror of
https://github.com/jackyzha0/quartz.git
synced 2026-03-25 15:35:42 -05:00
64 lines
1.5 KiB
Markdown
64 lines
1.5 KiB
Markdown
---
|
||
title: "05-filesystems"
|
||
tags:
|
||
- lecture
|
||
- cosc301
|
||
-
|
||
---
|
||
|
||
access control models
|
||
- DAC - subject centered
|
||
- MAC - object centered
|
||
- RBAC
|
||
- ACL
|
||
- list of who can do what things to which files
|
||
-
|
||
|
||
backups
|
||
|
||
devices for file systems
|
||
- device naming conventions under /dev explanation
|
||
- full
|
||
- easy, costly
|
||
- incremental
|
||
- updates only files that have changed
|
||
- level 0, 1, 2, 3, 4, 5 ... 9
|
||
|
||
UNIX file system
|
||
- tree 
|
||
- descriptions
|
||
- implementation
|
||
- inode ⇒ data structure documenting data about a file
|
||
structure of directory
|
||
- current working DIR is always in memory
|
||
|
||
soft vs hard links
|
||
- hard link must always point to data - to delete a file with hard links you must also delete all the hard links
|
||
- link to _actual inode_
|
||
- soft links can point to a non-existing file
|
||
- link to file _name_
|
||
- can link incompatible file systems e.g., windows, xerox. i.e. fs's that dont use inodes
|
||
|
||
advanced file attrs
|
||
|
||
special files
|
||
|
||
journaling
|
||
- logs changes to journal before writing
|
||
- impact on performance requires data be written twice
|
||
- **question** why not just write a description of the change
|
||
- all or nothing operations: ensure consistency
|
||
-
|
||
|
||
creating FS demo
|
||
- `# dd if=/dev/zero of=loopbackfile.img bs=100M count=10 `
|
||
- `# du -sh loopbackfile.img `
|
||
- `# losetup -fP loopbackfile.img `
|
||
- `# losetup –a `
|
||
- `# mkfs.ext4 /root/loopbackfile.img `
|
||
- `# mkdir /loopfs `
|
||
- `# df -hP /loopfs/ `
|
||
- `# mount -o loop /dev/loop0 /loop`
|
||
- `# mount | grep loop`
|
||
|