Some rearrangement of fdisk & gdisk formats has gone on in my mental absence from such things. The range of disk type formatting options has been expanded vastly. In fact you can't see the wood for the trees anymore. All these historical, theoretical, optional, reserved, hypothetical & other-dimensional formats hide the half dozen or so that actually get used.
I wanted a windows compatible usb disk. So I gave a new 32G disk to my son and asked him to format it. I then threw this 32G disk in a slot and examined it with fdisk and gdisk.
Code:
Welcome to fdisk (util-linux 2.37.3).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
The device contains 'vfat' signature and it will be removed by a write command. See fdisk(8) man page and --wipe option for more details.
Command (m for help): p
Disk /dev/sdc: 29.3 GiB, 31457280000 bytes, 61440000 sectors
Disk model: USB DISK
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x500a0dff
Device Boot Start End Sectors Size Id Type
/dev/sdc1 1948285285 3650263507 1701978223 811.6G 6e unknown
/dev/sdc2 0 0 0 0B 74 unknown
/dev/sdc4 28049408 28049848 441 220.5K 0 Empty
Partition table entries are not in disk order.
Command (m for help): q
Gdisk seems no better
Code:
bash-5.1$ gdisk /dev/sdc
GPT fdisk (gdisk) version 1.0.8
Partition table scan:
MBR: MBR only
BSD: not present
APM: not present
GPT: not present
***************************************************************
Found invalid GPT and valid MBR; converting MBR to GPT format
in memory. THIS OPERATION IS POTENTIALLY DESTRUCTIVE! Exit by
typing 'q' if you don't want to convert your MBR partitions
to GPT format!
***************************************************************
Exact type match not found for type code 6E00; assigning type code for
'Linux filesystem'
Exact type match not found for type code 7400; assigning type code for
'Linux filesystem'
Warning! Main partition table overlaps the first partition by 34 blocks!
You will need to delete this partition or resize it in another utility.
Warning! Secondary partition table overlaps the last partition by
3588823541 blocks!
You will need to delete this partition or resize it in another utility.
Command (? for help): p
Disk /dev/sdc: 61440000 sectors, 29.3 GiB
Model: USB DISK
Sector size (logical/physical): 512/512 bytes
Disk identifier (GUID): CB98FFF4-3128-41D2-8A7F-BA9F69E15962
Partition table holds up to 128 entries
Main partition table begins at sector 2 and ends at sector 33
First usable sector is 34, last usable sector is 61439966
Partitions will be aligned on 1-sector boundaries
Total free space is 61439933 sectors (29.3 GiB)
Number Start (sector) End (sector) Size Code Name
1 1948285285 3650263507 811.6 GiB 8300 Linux filesystem
Command (? for help):
I can only conclude Windows 10 hasn't a clue either
. It's not comforting to know that Windows 10 thinks my 32G disk is good for 811.6G, and I can't mount any of those partitions in linux.
Can someone point me at a shortlist of frequently used formats?
