I feel like an idiot realizing block devices are just... block devices.
They just hold data.
Shocker, I know.
But it just hit me when playing around with LVM. I can create a PV directly on a disk. I can even directly format a disk with FS. Floppies don't tend to have a partition table either. On the other hand, I can partition a partition. I can also just write a Tar directly to disk, like with tape. Or any file.
But with multiple files it starts to become a problem. A-ha! I can just write files to partitions just the same to make reading them simpler.
In this case:
Device Start End Size Name
/dev/sda1 2048 70704 33.5M Limahl - Never Ending Story
/dev/sda2 71680 127492 27.3M Alphaville - Big in Japan
/dev/sda3 129024 201967 35.6M Alphaville - Sounds Like a Melody
/dev/sda4 202752 259447 27.7M Bronski Beat - Junk
/dev/sda5 260096 324229 31.3M Chris De Burgh - High On Emotion
/dev/sda6 325632 386300 29.6M Jermaine Jackson - When the Rain Beg
/dev/sda7 387072 437492 24.6M Kylie Minogue - The Loco-Motion
/dev/sda8 438272 493179 26.8M Mauro - Buona Sera Ciao Ciao
/dev/sda9 493568 545532 25.4M Olivia Newton-John - Xanadu
/dev/sda10 546816 613761 32.7M Radiorama - Yeti
I don't know if it's the limitation of GPT, but fdisk let's me theoretically get up to 2^32^ partitions (default is 2^7^). In practice, this will be lower.
For example:
Expert command (m for help): l
New maximum entries (1-4294967295, default 134217728): 268435456
Not enough space for new partition table!
Expert command (m for help): p
Disk /dev/sda: 57.3 GiB, 61524148224 bytes, 120164352 sectors
Right now I just did it manually. Check file size, divide by sector size, add one if remainder, make partition of that number of sectors, name partition, write partition table, copy file with dd and repeat.
But I should try to automate this. It could be a bash script, but I want to learn C beyond basics, so I guess I should try writing it in that.
Take destination drive and files as arguments, then do what I wrote above. And try not to nuke the wrong disk in the process.
On the other hand, I am so lazy I can't typically even start with my hobbies. Which sucks because I want to, I just can't... start.
Anyway, hundreds of files and partitions can't be processed by hand any easier.
Well it's a program that turns a huge array of bytes into a directory tree by allocating some of these bytes for data structures holding directory structure, metadata etc. The simplest to understand example would be FAT16 or floppy formats from 80s home computers. These had a lot of shortcomings, which were solved by more and more complex data structures.
You can write a Python script that reads /dev/sda byte by byte and displays the directory tree. That would be a simple file system driver.
But what of we left the tree building away and add tags and groups and metadata instead?