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I am german and the explanation at the beginning is too good! :-D

I'd love to see a "how does the Action Replay work?" video!

Actually, Atari ST formatted disks could be read on DOS-PCs directly, if these were formatted either with TOS 1.04 upwards, or a 3rd party formatter like Hyperformat. Only TOS 1.0 and 1.02’s formatting routines had a bug that prevented DOS recognizing the disks from the ST. As you mentioned, the other way round (PC->ST) was never an issue. The 1st program on the ST to go beyond 880KB was Hyperformat from Claus Brod and Anton Stepper. TIL that the Amiga went far beyond 900KB! Its "full track" tricks can’t be done on the ST, as this one uses a "classic" floppy controller WD1772 that works per sector.

Reminds me of the various “super floppy” formats, like floptical and ls-120.

Lol you sound like a chip munk 😀

How Floppy disks actually work always makes my head spin. The multiformat disks always seem like magic to me. A disk that can be read on the Amiga, Atari ST and DOS!

This looks familiar. Saw it in catalogues and the local Tandy branch here in Australia. Never actually owned it, though. I do, however, still have the 60-in-One from the same family.

Disc duplicators would always use new discs because they were more reliable, however sometimes they didn't. What would happen is that there were shortages that sometimes occurred. It's not a shortage in that floppies became scarce on the shelves, but in bulk purchases. When duplicators bought discs they bought by the thousands at an extremely low price. When they couldn't buy at that low price they went to disc reclaimers who were supposed to clean the labels and blank the discs (at one place I knew of they would literally hose off the discs with just tap water then scrape off the labels and then run big magnets over them and lastly hang them up with a fan (those were the super cheap discs! no returns). But sometime when deadlines were crazy shortcuts were taken and you get a huge box of all different discs with whatever was on them "good luck"

Hello Rob, I really enjoy your video's and now i am totally back into AMOS since the 90's (UAE in Windows). Now i am playing with embedded assembly code in AMOS, but i just don't remember exactly how to execute it. I know i can put assembly code in strings like a$="move.l ...." etc, but then? Maybe a stupid question, but if anyone could help me, i would be glad :-) Its been a long time since i did this on my Amiga. (btw, I use Amos Professional. Don't know if that matters). Thank you for all your great videos!

fascinating. I guess, there is no way to slow down the disk during reading and writing in the outer sectors. otherwise, you could squeeze 1,5mb on such a disk.

Amazing the flexibility of the way floppies can be addressed (and how flexible the hardware is to allow this).

Some Amiga magazines published an occasional dual format disk that mixed in ST formatted tracks in areas that weren't strictly required by the Amiga OFS. Also, FFS was available for hard drives, but I'm not sure if it did similar low level trickery as with floppies. I remember it being perceivably faster with caveats - pre-2.0 Kickstart ROMs could not boot FFS partitions although these could be mounted after booting off of an OFS partition, and, there were people who backronymized FFS for what you actually WOULD think because they had their FFS partitions get repeatedly corrupted. I remember there was some software for the PC that could also, with some disk controllers at least, write a "huge" extra amount of data on DD and HD disks... also I managed to buy some cheap disks of questionable quality that were not very good at the standard HD format, but when I configured a standard 3,5'' HD drive as a 1,2MB 5,12'' drive in the setup as my B drive, it would happily use that (almost) 1,2MB per disk without issues, while in 1,44MB format those same disks would have so many bad sectors that the usable space went way below 1MB. It is possible that these were actual old DD rusts packed in HD shells and wished Bon Voyage. This seemingly goes to show that the disk rusts had a rather sharp limit of frequency they could reliably record, and lowering the recording frequency only by approx. 17% made them work way better.

I think this is the first time I see this YT channel, and I'm positively surprised with accuracy of ST's tidbits. Been playing around with floppies back in the day (ST 3.5/5.25/SD/DD/HD, synchro express, 800's 1050/551, etc.), and watching this was a nice flashback.

software publishers would send the unsold software to get recycled.. they would magnetically erase the disks and bulk pack them for software distribution publications like the aol mailer and magazines.

Back in the late 90s, early 2000s, someone on a local BBS gave me access to the internet through his parents' account on a university computer, and I went nuts downloading pictures from newsgroups, so I needed somewhere to put them all. I had an HD floppy drive, but I was always looking for ways to fit even more on a disk. I used a special driver that let the drive format an extra 2-3 tracks. l also used a copy of PFS/AFS on that drive. As I recall, it started out as freeware called Professional File System, before going commercial and being renamed to Amiga File Safe, or something like that. All the magazines gave it glowing reviews and claimed that it was 100% impossible to corrupt a disk with it. HAH!!! While it did allow me to squeeze even more data onto each disk, I accidentally discovered that it was shockingly easy to completely corrupt a disk simply by popping it out of the drive at the wrong time while writing a file. With a little practice (on spare disks), I was able to do it every single time. And of course, there were no recovery tools of any kind to fix such corrupted disks. "Wait!" I hear you say, wasn't there a version of DiskSalv that worked on AFS? Yes, but not for floppies. If your AFS formatted floppy disk got corrupted, you were SOL. Worse, all of the disks I formatted this way were prone to phantom errors. What I mean by this is I would be copying files off a disk and it might claim that one of them can't be read. If I then popped the disk out and re-inserted it a few dozens times, eventually it would read that file. One time I had about a dozen disks, each filled with Zip files, and I was copying them to an Iomega Zip disk. When I got done, I had three disks with at least one file each that wouldn't copy, no matter what I tried. I set those disks aside and forgot about them for about a month. One day I decided to try again, and those files copied perfectly on the first try. I now wish I hadn't messed with this extra crap and had just used the normal FFS format.

The Acorn ADFS type F format allowed 1.6Mb on a standard floppy.

the Floppy i know had 1,44MB (1,38MB with a filesystem)

My AUI disk 87 (Aug 96) also had its label stuck on another label: PTR Program/Graphics 1 from WordPerfect 1989.

Cool stuff Rob. I had not heard of that format as, being from Canada, I had subscriptions to AmigaWorld and Amazing Computing, and the only UK magazine I regularly bought was Amiga Format. I do recall AUI but for some reason it just didn't appeal to me. I recently built a DrawBridge using a spare Arduino and have been having fun with that. Thanks for all the cool stuff you are doing with these great old machines. Any chance you will be attending this year's World of Commodore show in Toronto? 😄

Great video 👍👍

So it is kind of like Shingled magnetic recording (SMR) in some hard drives. Can you try this trick on 1.44 HD and wishful thinking 2.88 ED Disks. Only wish that 2.88MB disk became popular in the day.

Slight variance in speed would only be a problem if writing to the floppy, it would overrun and corrupt the first sector. I suspect most cover disks didn't write to the original media. ST allows whole track read or write but the problem with track write is that some values are reserved as commands to create gaps etc so is less versatile than the Amiga there.

Ahhhh memories… I us to use 83 tracks and 11 sectors on my ST.

I still have my 1.76.MB Drive on my A500+ which can be format to nearly 2.MB. In have 3 external floppy drives in total which were put to good use on games that were on many floppies.

I remember having a few coverdisks on old reused disks.

floppy.device (disk/misc/floppy43.lha on Aminet) can store even more, 1120 kB on a standard DD disk.

Really interesting. I had loads of AUI disks and never ran into any issues with those disks.

Back in the day as a kid I was more patient and had more time as I didnt have all the "obligations" I now have as an adult. Work. Shopping. Repairing things. Cleaning the house. Paying bills. etc.

All these cool gadgets that are out for Amigas and they always seem to be OOS!!!!!!

i love this idea..

I may have misinterpreted what you explained but can you assign another area of memory that holds the same map data in another way? Poke this secondary memory, level map with number values that match images. Your level designer then applys a variable - img - that Peeks the same location (in memory) on screen, from this secondary memory screen map of image numbers. This approach would remove the time consuming instruction of using the IF command. 'display memoryaddressx, memoryaddressx, memoryaddressimagenumber'

I have a few of these disks in my archive stash, now I need to go get them and take a look.

Some tips from my use of amos in the 90s. If your on screen ghosts/aliens/ships etc use colours closer to colour zero they'll be rendered quicker. Line numbering in your code will often slow things down a bit when you code each line by a count of 10 (10, 20, 30 etc) renumber it as 1,2,3...99,100 etc. Try and place you main game routines at the start of your code instead of further along. They'll be read quicker. Like your blinking eyes using the copper chip: You can apply free and additional colour changes to gfx tiles where needed if your game is 8 or 16 colours only. Just leave blank areas in the gfx tiles. ..... I moved on to blitz basic 2. It takes a lot longer to master but is far, far faster than Amos and it compiles the instant you run your code. Blitzs performance on screen often matches the look and feel of commercial games.

Nice one! Tracks and sectors constantly remind me of XCopy 2d grid (8 rows by 10 columns + unused 9th row that can only have 2 columns - guess that'd be some extra for the DiskSpare?), or "formatting cyl 0 of 79" formatting disks in AmigaDos. Lol at the "that's what FFS stands for, not what you're thinking!" 😆

Wasn't there also a trick where you altered the disk read process. I think shadow of the beast used this to cram onto disk far more data than was normally possible

Really interesting video and will be interesting to see this in DiskFlashback

interesting video but very annoying that you don't have subtitles. the auto subs are pretty good. why deactivate them?

I suspect if PCs was just as reliant on floppies as the Amigas, they would properly have done this too.

Learned a lot on this Rob, thanks 👍

Is 2024 now not 1990.

Oh there were so many ways to format floppy disks! :-) Not just what personal and home computers did but also other hardware that used them. Early PC disk maintenance programs could do things like interleave the sectors which often gave a significant speed boost. And then there were formats with varying sector sizes. I believe the Ensoniq Mirage did this, giving the sampler just a little bit more savable storage.

With Atari st the max was with most of dd drives was 83 tracks and 11 sectors, 913 kb / 934 912 bytes formatted so that the formatted disk was accessible without any extra utilities.

Nice video

I discovered Diskpare on an Aminet CD that i purchased in the 90s. I used it on my A1200 it was brilliant being able to store all my music modules and instruments disks. I think i did and test with 10 of my most used disks and managed to cut the 10 down to 7 disks. Shame it couldn't be used to increase the size of my 60Mb hdd inside the A1200.

I have magnet with which risk of damaging floppy is least of our worries and I need to watch my fingers. Wonder how much sectors would this nice magnet would erase.

I always used 1.7M HD Discs back in the days on my PC formatted with VGACOPY. If I remember right it goes up to track 82, but I think sectors didn't change or I can't remember.

Interesting stuff indeed, I typically formatted disks on the ST at 820K (82 tracks 10 sectors) as I found 11 sectors to not be 100% reliable a lot of the time.

How have I only just discovered this?!? Excellent work, Rob! 🥰

I had a program on the PC that formatted a disk to 1.9MB instead of 1.44MB. No idea anymore what it was called, probably came from a shareware CD. Or a magazine.