...or whatever remains of it?

Yeah.
I finally found what I was searching for, usage of RW media similar to DVD-RAM. Only to find it's been removed from Linux Kernel: https://www.phoronix.com/news/Linux-To-Remove-pktcdvd

Worry not, something remains: https://www.kernel.org/doc/html/v6.1/cdrom/packet-writing.html

According to the DVD+RW specification, a drive supporting DVD+RW discs shall implement “true random writes with 2KB granularity”, which means that it should be possible to put any filesystem with a block size >= 2KB on such a disc.

And indeed, with DVD+RW disc, I can just do so. Even if it's really sub-optimal.

However, some drives don’t follow the specification and expect the host to perform aligned writes at 32KB boundaries. Other drives do follow the specification, but suffer bad performance problems if the writes are not 32KB aligned.

Anyway...

ext4 on DVD

So, yes. After initial format, I can just

mkfs.ext4 -b 2048 /dev/sr0

Might have been a coincidence as I just used an old disc and failing drive, but trying block size of 4096B made formatting extremely slow. No wonder, after inspecting the disc, it was clear the formatting fully re-wrote it, which didn't happen with 2048B BS.

tar

That worked as well. Exact command I used:

tar -vcf /dev/sr0 -b 4 files/

I am not sure if my setting for blocking factor made any sense whatsoever. I didn't retry this. As I said, old disc and drive. It would work in bursts, then get stuck for a long time. Writing ~500MB took roughly an hour.
Reading it worked well though.

Who needs an FS when you have tar.

Partition table on DVD - where the dreams fall apart

fdisk /dev/sr0

That... worked. I created GPT and added 2 partitions. After writing the changes, I reinserted the disc.
Aaaaaand... nothing.

You can see that there is indeed a GPT on that DVD+RW, which feels crazy. But, where are my partitions?
Looking in /dev, I found no mention of partitions.

ls /dev/sr0*
/dev/sr0

Let's check fdisk again:

fdisk -l /dev/sr0
Disk /dev/sr0: 4.38 GiB, 4700372992 bytes, 2295104 sectors
Disk model: DVDRAM GH24NS90
Units: sectors of 1 * 2048 = 2048 bytes
Sector size (logical/physical): 2048 bytes / 2048 bytes
I/O size (minimum/optimal): 2048 bytes / 2048 bytes
Disklabel type: gpt
Disk identifier: 6AE020A5-1F51-46A6-8741-C28915AF6208

Device      Start     End Sectors  Size Type
/dev/sr0p1    512  524799  524288    1G Microsoft basic data
/dev/sr0p2 524800 2294783 1769984  3.4G Linux filesystem

Hmmm. I didn't use root, so I got a hint from fdisk. I did re-insert the disc, so it should've been irrelevant now, but at least it pointed me to a potentially useful command.

# The kernel still uses the old table. The new table will be used at the next reboot or after you run partprobe(8) or partx(8).

sudo partx -av /dev/sr0
partition: none, disk: /dev/sr0, lower: 0, upper: 0
/dev/sr0: partition table type 'gpt' detected
range recount: max partno=2, lower=0, upper=0
partx: /dev/sr0: adding partition #1 failed: Invalid argument
partx: /dev/sr0: adding partition #2 failed: Invalid argument
partx: /dev/sr0: error adding partitions 1-2

Invalid argument?
Does it mean I can't load a partition table from a DVD?

LVM to the rescue? (no)

Short answer in this case:

sudo pvcreate -v /dev/sr0
  Cannot use /dev/sr0: device type is unknown

Finally at last, a disc directly playable with aplay

Obviously, I can write bytes to the disc, so this isn't special. But it feels cool.
I find it unfortunate that I can't simply take data of audio CD, playing it with aplay. But now I can at least do so with a DVD.

ffmpeg -i Stan\ LePard\ -\ Velkommen\ \(1996\).wav -f s16le -acodec pcm_s16le -ar 44100 -ac 2 tmp/velkommen.raw

And writing with dd

dd if=tmp/velkommen.raw bs=2048 status=progress of=/dev/sr0
57145344 bytes (57 MB, 54 MiB) copied, 16 s, 3.6 MB/s
27930+0 records in
27930+0 records out
57200640 bytes (57 MB, 55 MiB) copied, 33.49 s, 1.7 MB/s

It might be good to know this got stuck the first time at the end. So I used truncate to pad it with zeros to a multiple of 2KiB. Again, might have been a coincidence (sample size 2).

And finally, the dream is achieved:

aplay -f cd /dev/sr0
Playing raw data '/dev/sr0' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo

Now I could perhaps try to make a script/program which would take list of files, convert them to raw PCM, record track byte offsets and other data (like track title), concatenate the audio, add the info data in some specific format, and also have a program/script to read the info and play the tracks!

Re-inventing the ~~wheel~~ disc.

I guess it's obvious why I am asking.

I am just too dumb for it. Like, genuinely. I only passed through HS because on final exam from literature the teacher gave me a full answer. Actually, I didn't even get that, she had to tell me "Write that down!" because I was just thinking "Why are you telling me that?"

In 1st semester I didn't pass 2 subjects. Now in 2nd one I only got to final exam of 1, which I'll have to retake and I don't feel like I'll pass it either. The only subject I was really interested in passing I didn't manage to get through due to me being late with assignments.
I am still planning to finish the last one just because I want to get rid of my Firefox tabs and I already spent 32 hours on it. The previous one took me 50 hours only for partially completing it. I estimate full completion at 65 hours, if I did that one, which I may do as well later.

Which isn't much time, actually. When I do the math based on credits, main part (time until exams) of first semester being 12 weeks, second 13 weeks, it averages out at 61h/week of work (combined lectures + seminars + expected study time and assignments).
2nd semester at 52h/week
1st semester at 71h/week.

Regardless of how I manage the exam, I won't pass to the second year.

Oh, it gets worse. I found out I was supposed to select my subjects for next year. They only sent us the email about that the day prior (2pm).
I skimmed it, OK, selection starts June 4th, went to check the UI, nothing there. Turns out, the selection deadline was on that same day, at 9pm, so I missed it by 3 hours.
Worse yet, though not applicable to me, the school also "thinks" of foreign students. In this case by notifying them only 12 hours before the deadline as well as informing them that the information in English is outdated (and that's all they did about it).

It's album named Virgin from Lorde. Not quite my taste of music, but the disc itself is pretty interesting.
Though it does have issues. Since the reflective layer is very thin, a lot of light passes through.

Even beaming through the lid:

Here's a blog post about it on Hackaday, also showing the lower signal amplitude compared to regular CD.
For me, so far it worked in 2 out of 4 CD players/drives. And I didn't even try with those that can't read CD-RW, as those can probably be crossed off right away.

Anyway, what happens when it's upside-down? Obviously, "doesn't work" is the answer. But at least we can see the lens dance a bit, trying to read the disc:

If you're worried about data consumption, this video is less than 300KB in size thanks to AV1. ^Although^ ^it^ ^took^ ^7^ ^minutes^ ^to^ ^encode...^

And something funny to add.
I ripped it once, there was weird noise, so I tried it again. I played random track, "David", and skipped through it. It sounded corrupted. So I tried playing it directly using VLC. Still the same. Thinking it was the drive, I tried my Discman. Same issue.
Is the disc bad?
But, after finally getting the track from the internet, I found it just sounds like that.

I think someone screwed up on "3 business days to pick up".

Software often has pretty good documentation. But real-world things don't.
And if I don't know exact steps to do something and what to expect, I just can't really push myself to try it the first time. That can be put into an interesting sentence.
"I can't do it because I haven't done it."

Recent example:
I want to take a bus. But I haven't yet used the company that operates these buses. I do have an RFID card with e-wallet that is compatible with this company. That is because they operate as intercity transport in the same region, and same tickets are valid there. Except for one line, the one I am most interested in.
Now comes the problem.
How am I supposed to board? How do I buy the ticket? On other lines, am I supposed to prove I have one?

Before I start with the issues of unknowns, I should mention I so far spent 3 hours trying to find the information. That includes searching for videos which may show what others do in the background. In one similar case I found the answer from a TV news report filmed near a bus stop, and my answer was in the background.

So, boarding. Is it front doors only, or do the doors not matter? I've seen both.
Purchasing the ticket: There was a mention of possible cash payment, buying the ticket "from the driver". I managed to find photos from inside the bus, and to further my confusion, there were 3 terminals. All of them RFID-compatible.
2 are ticket validators next to both doors.
1 is on-board computer (apprears to be TransData Vesna model) along with a ticket printer and RFID terminal, operated by bus driver.
If it was just one of those, I'd know what to do.
I found one video from that special line. The person presented a QR code of valid ticket to the driver before boarding. But I don't use that payment method.
But if it's front doors only, why are there validators in the rear? Or was that just something specific to this line?

Now, I could do the one obvious thing, ask the driver. But I really hate talking to people I don't know.
An alternative I am contemplating is sending an e-mail to the company with my questions. They do have one for customer questions.

This is always a problem if I don't know exact steps for something. And even then I am still really anxious before I actually do it for the fist time.

$ pacman -Si apt
Repository      : extra
Name            : apt
Version         : 3.1.4-1
Description     : Command-line package manager used on Debian-based systems
Architecture    : x86_64
URL             : https://salsa.debian.org/apt-team/apt
Licenses        : BSD-3-Clause  GPL-2.0-only  GPL-2.0-or-later  MIT
Groups          : None
Provides        : None
Depends On      : systemd-libs  libseccomp  perl  xxhash  dpkg  gnutls  bzip2  sequoia-sqv  xz  gcc-libs  lz4  bash  zlib  zstd  db  libgcrypt  glibc
Optional Deps   : None
Conflicts With  : None
Replaces        : None
Download Size   : 2.63 MiB
Installed Size  : 8.24 MiB
Packager        : Alexander Epaneshnikov <alex19ep@archlinux.org>
Build Date      : Mon 11 Aug 2025 08:52:43 PM CEST
Validated By    : SHA-256 Sum  Signature

https://archlinux.org/packages/extra/x86_64/apt/

Not particularly pleased about the decision when OpenVPN is the most supported protocol.

Meanwhile their competitor IVPN even does IPsec.

Note: I haven't yet. The following text is not an answer, and might not be worth reading. (Chance: approx. 95%)

Previously posted in mildly interesting a year ago, doesn't qualify anymore: https://lemmy.sdf.org/post/18714104

Probably disintegrating, I don't know. But now I'll finally have to buy new ones. Currently there's 6 oozing points in total. 3 are minor, one is now inactive (the 2024 pimple), one I taped over, but it's starting to overflow, and one near the jack is major.

I now cannot plug them in without getting sticky residue everywhere. Also the rubber on the outside is starting to crumble a bit.
I am a cheapskate, but this may be their end.

 ^    American
^ ^   Megatrends

Version 2.17.1255. Copyright (C) 2018 American Megatrends, Inc.
**** UTC-5XXF BIOS H1.11 (03/09/2018) ****
Press <DEL> or <ESC> to enter setup.

BIOS Date: 02/22/2018 13:43:17 Ver: 5.0.1.1
Processor Type: Intel(R) Core(TM) i5-6300U CPU @ 2.40GHz
Processor Speed: 2300 MHz
Total Memory: 8192MB (DDR3 1600)

USB Devices total: 0 KBDs, 1 MICE, 0 MASS, 1 HUBs

Detected ATA/ATAPI Devices...
SATA PORT2: LITEON K8-L1256, S.M.A.R.T Supported

A configuration change was requested to Clear this computer's TPM (Trusted Platf
orm Module)
WARNING: Clearing erases information stored on the TPM. You will loose all create
d keys and to Clear the TPM crypted by these keys.
Press ESC to reject this change request and continue

Retyped by human.

Preface

I'll be going to college that is a bit further away (i.e.: daily commute not possible) and will have to live in a dorm (can't afford anything better).
Unfortunately, no single-bed rooms seem available and I have a bit of an issue with being with people (any).
Currently I live with parents, which for me is also not easy to deal with. I usually spend most of the days on toilet (separate room from bathroom in our case) sitting on ground, with laptop on the closed toilet itself, as a room replacement.

Personal preferences (in order of importance)

1. Room privacy/separation
2. Bathroom privacy
3. Distance from faculty
4. Food access

Buildings

Let's give them some names...

1. CRAP (Can't Receive Any Privacy)
   • 2-bed rooms
   • Shared bathroom
   • 4.5km away from faculty
2. PRISON (Packed Room Is Single Only Negative)
   • 2 and 3-bed rooms, 2 rooms per cell
   • One bathroom per cell
   • Cafeteria
   • Buffet
   • 1km away from faculty

Available information

• Total number of beds
• Remaining number of beds (since some are occupied by prior students)
• Number of current pending reservations (i.e. how many want the room)
• Price (irrelevant)
• Nationality of interested/housed students

Current situation

Naturally, most students prefer to live in PRISON rather than CRAP, hence all those rooms already have either current students or interested ones.
As of now, after 2 days (5 days remaining for current round), the CRAP still has 11 rooms with nobody in them and no reservations.

Possible strategies and their flaws

Risky, potentially high gain

Set one of the empty CRAP rooms as high priority. If it survives the next, final round without additional reservations, I could have a separate room.
Flaws: If it does not, I'll end up with a random roommate nevertheless, but in a shitty far away building with shared bathrooms and no cafeteria and buffet. In the end, only piling up drawbacks. Additionally, there seems to be currently empty rooms with multiple reservations in CRAP. Either these are friends, and it's nothing to be worried about, or, there's people who prefer a roommate for whatever fucking reason.

Expected misery

Choose any 2-bed room in a PRISON cell, for sure getting a room in better, nearby situated building, with one-person-at-a-time bathrooms, and the cafeteria and buffet.
Flaws: There will be a roommate, and my only choice can be between their nationalities, but I will not be alone.

So should I take one of the PRISON cells, or end up stuck in CRAP?

(Yes I had fun with the acronyms)

Or just wrong UUID in fstab? (And nobody tested it when changing drives)
It did boot partially, plus the "Dependency failed for /boot/efi", which it probably wouldn't start booting without.