[ TIL ] Operating System | Filesystem Types

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Filesystem

used to keep track of files and file storage on disk.

• Windows is recommended to use NTFS Filesystem

• Ubuntu is recommended to use ext4 Filesystem

• FAT32 supports reading and wrting data to Windows, Linux, Mac Os

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Disk Anatomy

• Partition -> the piece of disk you can manage.

• Volume -> when a filesystem is formatted on a partition, it becomes a volume.

• Partition Table -> tells the OS how the disk is partitioned.
  - MBR(Master Boot Record) : traditional partition table, mostly used in Windows. only have 4 primary partitions
  - GPT(GUID Partition Table) : new standard for disks. has one type of partition. you can have as many as you want.
  

• UEFI -> default BIOS for newer systems. to boot, must use GPT.

• Mounting -> make something accessible to the computer, like filesystem or hard disk

Windows

• Diskpart -> terminal based tool for managing disks right from the command line.
  - list disk : list disks
  • select disk 1 : select a disk
  • clean : clean the disk
  • create partition primary : create partition in selected disk
  • select partition 1 : select created parition
  • active : make selected partition active
  • format FS=NTFS label=my-thumb-drive quick : format disk

Linux

• Parted Tool -> supports both MBR and GPT partitioning

1. Partition a disk

   • parted -l : list disks
   • parted /dev/sdb : select a disk
   • print : show status
   • mklable gpt : make lable with string
   • mkpart priamry ext4 1MiB 5GiB : make partition with necessary informations.

2. Add Filesystem

   • mkfs -t ext4 /dev/sdb1 : add filesystem

3. Mount for use

   • mount /dev/sdb1 /my_usb : mount the disk to a directory
   • now you can read and write data in the disk

• /etc/fstab : add an entry automatically mount filesystems when the computer boots
• sudo blkid : shows UUID for block device IDs aka storage device IDs.

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Swap

• Virtual Memory -> how our OS provides physical memory available in our computer(like RAM) to the application that run on the computer
• swap space -> where we allocate virtual memory on our hard drives

1. mkpart primary linux-swap 5GiB 100% -> make swap partition
2. sudo mkswap /dev/sdb2 -> make swap space
3. sudo swapon /dev/sdb2 -> enable swap on device

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Files

when OS handles files
it actually handles

• file data -> actual contents
• file metadata -> owner, permissions, size, location etc..
• file system

Windows

• MFT -> Master File Table
  every file on volume has at least one entry.

• shortcut -> another file, another entry on MFT. has reference to some destination.

• symbolic link -> points to the name of another entry or another file. OS treats then like substitutes for the file

Linux

• inode -> we store inodes in an inode table and they help us manage files on our file system.
• softlink -> point to another file
  ln -s
• hardlinks -> link to an inode
  ln

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