Grading homeworks 2, 3 and 4 continued
Pi for all
Find your own Pi! If you are in a group, help everyone to split the Pi.
There are 23 students in the class. There used to be 15 Pi’s; now there are 27. Also, Raspberry Pi systems can be replaced with Raspberry Pi3 systems!
- uncacsci-pi-b — 1 account
- uncacsci-pi-e — 2 accounts
- uncacsci-pi-g — 3 accounts
- uncacsci-pi-h — 3 accounts
- uncacsci-pi-o — 2 accounts
- uncacsci-pi-p — 2 accounts
- uncacsci-pi-r — 1 account
- uncacsci-pi-u — 1 account
- uncacsci-pi-v — 2 accounts
- uncacsci-pi-y — 1 account
- Comparison of file systems
- Design of File Allocation Table (FAT) file system
- Microsoft EFI FAT32 File System Specification
- ext4 disk layout
- extents, sequential lists, trees, extants
- Directory search — sequential list, b-trees, Htrees
What is the OS (Linux) view of a file (again)
Not so quick answers
Links — pointers for files
- device id and inode numbe — “address” of a file
- reference counts — number of hard links
- symbolic links — soft links
- Using the ln command
- Making links with Python with the
os module —
Access Control Lists
- Required for SELinux
- getfacl and setfacl
- You better just find some examples to ponder
- task — make a file than can only be read by you and two others
Have you written Python programs to read and write files?
A lab part
Disecting a file system
Try to work to the root directory part of the finding a file exercise.
Getting an account
Find your own Pi. Create your own personal account on your own computer.
A file exercise — Homework 7
Make sure your Pi doesn’t have any logical volumes. Run pvscan, vgscan and lvscan to find logical volume structures. Use lvremove, vgremove and pvremove to delete them.
Keep the partitions for / (/dev/mmcblk0p2) and /boot (/dev/mmcblk0p1); but delete all others.
Partition your Pi to match the following and then reboot.
Device Boot Start End Sectors Size Id Type /dev/mmcblk0p1 8192 131071 122880 60M c W95 FAT32 (LBA) /dev/mmcblk0p2 131072 16908287 16777216 8G 83 Linux /dev/mmcblk0p3 16908288 27394047 10485760 5G 83 Linux /dev/mmcblk0p4 27394048 31422463 4028416 1.9G 83 Linux
Now format /dev/mmcblk0p4 to be an ext4 file system.
Within the /dev/mmcblk0p3 partition create
a volume group
csci373VG with three logical volumes:
msdos373LV with 32 MB,
ext373LV with 2 MB, and
xfs373LV with 2 MB.