Hacker News Reader

Comment by Zenst | Hacker News Reader

I vaguely recall that people used to get their atari floppies and format in a MSDOS machine as it would yield a slightly bigger capacity - something to do with default format on DOS using more tracks. That was until alternative floppy formatting tools came about on the Atari scene and there was one that was also great for copying discs - going to bug me to recall it's name, but was one of those utils that had a cult rep in its day in atari land.

[EDIT ADD] Ok had a dig around and the tool most used was Fastcopypro - https://sites.google.com/site/stessential/disks-tools, was useful to do fancy formats for extra capacity if you had good quality discs as well as copying/backing up discs

View on HN

Both DOS and Atari used FAT format. The capacity was identical, but MS-DOS would have trouble reading Atari ST floppies because Atari had followed the published standard and wrote two copies of the allocation table to the disk, and MS-DOS would only write one and overwrite the second one with data and corrupt the disk. The 'extra space' was the space that was supposed to be taken by the redundant file allocation table.

The rule was if you wanted to move files between systems, you had to format the floppy on MS-DOS, then you can use it everywhere. If you formatted on the Atari and used it on MS-DOS, you would end up using it nowhere.

I didn’t grow up with floppies, so pardon my ignorance, but two questions: (1) which FAT? I figure it can’t be FAT32, but that still leaves FAT12 and FAT16, both of which Microsoft helped develop. And (2) since Microsoft helped develop it, were they just not following their own spec? Because that doesn’t make sense (not that you’re wrong).

Of course MS didn't care about their 'standard'. They assumed they're the only ones using it and/or don't really care about breaking other systems.

Sometimes they broke other systems on purpose, e.g. https://en.wikipedia.org/wiki/AARD_code.

The other direction, too: "DOS isn't done until Lotus won't run!"

FAT afaik is also known as FAT12 - nice explanation in the wiki over the differences and some history aspects: https://en.wikipedia.org/wiki/Design_of_the_FAT_file_system

MS-DOS was also not the only DOS on the market. DR-DOS was very popular at the time of the Atari ST. As far as I know DR-DOS also followed the published specification and Digital Research (DR) was Microsoft's biggest competition. Atari also used Digital Reasearch's GEM as their "desktop" GUI. GEM was a direct competitor to Microsoft's new Macintosh-killer product called "Windows". CorelDraw and WordPerfect used GEM, MS Word and MS Excel used Windows.

Draw your conclusions.

That screenshot of fastcopy just brought memories flooding back! I was one of the strange kids in the 90's who had an Atari while everything else in the world was windows, the FAT format was invaluable for me as I could easily transfer files between home, school and other kids computers... I didn't appreciate at the time that this kind of compatibility wasn't a given.

I remember seeing a tool that could be used to punch a hole in floppy disks in order to double the capacity. I didn't have such a tool, but I did have a cheap soldering iron. I ended up with a bunch of 3.5" floppy disks with holes melted through them.

Thinking back on it now, I'm surprised that I didn't damage the disk with the heat of the iron. Then again, maybe I did and didn't notice because I was 12.

Flip-it?

https://www.computerhistory.org/collections/catalog/10271130...

Might have been that brand. I remember seeing what it did and then figuring out how to get a hole in the 3.5" disk without cracking the plastic.

I've seen it used - IIRC the problem is that the media isn't rated for the storage that you're now asking of it, so while it may survive being written/read a few times, it'd fail sooner.

Can confirm. I used to drill holes with a... well, a drill.

Totally worked. Capacity increased. Until one day your files were corrupted. And that day often came soon!

It might fail sooner, but you were banking on it essentially just being a binning distinction, that they didn't really do any testing either way and just stuck them in cases with or without the hole depending on what they thought they could sell at the time.

Did I lose files on fake doublesided disks? Yes. Did I lose files on real doublesided disks? Also yes.

You're basically overclocking your storage medium.

I remember a tool called 2M on DOS, which allowed formatting 1.44M disks to non-standard capacities, up to ~1800k or so...?

Edit: https://en.wikipedia.org/wiki/2M_(DOS)

As someone who didn’t grow up with many floppy disks, how was one able to format a floppy to have a different capacity? I know there’s different “formats” such as DOS, C64, etc, but I don’t understand why?

I have heard about how formatting a floppy involved placing the tracks and how modern hard drives have “hard sectors”, but for some reason, it’s not “computing.”

Basically your floppy disk is formatted on each side with a number of tracks, each containing a number of sectors of a given size. [1]

The standard 720KB 3.5' floppy disk as used by the Atari ST used 80 tracks of 9 sectors.

With these tools you could format with, say 11 sectors instead of 9 and boost capacity to 880KB (I think the Amiga was doing that as standard).

[1] https://en.wikipedia.org/wiki/List_of_floppy_disk_formats

On top of that some tools (I used fdformat) shifted the sectors to speed up sequential reads, i.e. have the first sector of the next track rotate in under the r/w head right as the head arrives.

Edit: another unrelated practice was buying up cheap(er) single-density disks, which were distinguished by the lack of a marker hole opposite the r/o protection slider, and used only one side of the medium for data. By drilling it out, one could trick the drives into using both sides, which usually worked out just fine. Mentioned here [1]

[1] https://en.wikipedia.org/wiki/Double-sided_disk

Ah yes, interleaving of the sectors. More prominant with early HD's and using tools like spinwrite to optimise the interleaving. Today it's all 1:1 as processing from the heads just been fast enough for decades to handle the speeds.

Spinwrite still exists, though in the early days/versions it was the golden tool for tuning up a system and could make huge differences. Like double your drive speed and more in some instances, but talking late 80's early 90's here when interleaving was thing and mid 90's 1:1 became the norm and made it moot. https://www.grc.com/Spinrite.htm

Single-density is not the same as single-sided. There are single-sided double-density disks.

I seem to recall having a program called "Twister" that could format disks like this.

The floppy drive has a stepper motor that controls the placement of the read/write head above the disk.

In the ST era, the control of that motor was directly under the control of the operating system. For an 80 track disk, the movement required to step between tracks was a certain known amount.

If you formatted the disk with the tracks spaced closer together, by altering the stepper movement during that process, you would 'magically' get more space.

Weren’t there special compression softwares that added even more capacity?

I don't really remember any: my main recollection as an ST user was the format programs that let you increase the track count and the sector density.

I recall the default format was 9 sectors, 80 tracks, 2 sides with 512 bytes per sector = 720KB, and you could push up to sometimes 82/83 tracks and maybe 10 or 11 sectors to get more out of a diskette.

Actually, I think my ST originally came with a single-sided floppy drive and had to be upgraded.

The initial release of Atari's has single sided drives, I think the 1040ST had Double sided though, they did upgrade that shortly afterwards I believe to enable the marketing bods to show a larger number they could compare to the Amiga. So was only early 512STFM systems and those had a red drive light and the double sided had a green one if my memory holds.

Sad thing was, due to the early single sided models, many games would limit to 720k so as to not limit there market. That saw games that would happily fit upon a single double sided disc, cast upon two floppies forcing switching. So that small batch of single sided initial release systems, really did have a legacy impact that lasted for years and did it no favours.

There was, can't recall the one that was popular prior to Microsoft adding https://en.wikipedia.org/wiki/DriveSpace MSDOS 6.0

Stacker was pretty common in the early 90s.

That'd probably be DoubleDisk or Stacker. https://forum.winworldpc.com/discussion/10401/software-spotl...

>In the ST era, the control of that motor was directly under the control of the operating system.

No, it was under control of a stepper motor driver circuit located directly on a Floppy drive pcb. This driver in turn received instructions from a dedicated Floppy drive controller (WD1771 and compatibles).

> For an 80 track disk, the movement required to step between tracks was a certain known amount.

"certain known amount" being one step per track

>If you formatted the disk with the tracks spaced closer together, by altering the stepper movement during that process, you would 'magically' get more space.

Above is incorrect.

Its impossible to move HEAD stepper motor between tracks. Floppy drive has a STEP (/STEP) and DIRECTION (/DIR) pins. All you are able to do is pick direction and step one track at a time. Step distance is Fixed. The whole point of using a stepper motor is you dont have to worry about head tracking/alignment.

The only personal computer Floppy drives with flexible head positioning all used voice coil head actuator - Floptical, LS-120/240, Zip drives etc.

https://twtext.com/article/1263702402886057984

The disk controller chip let you seek track by track. No fine control at all.

You could format extra tracks, if you felt lucky. Usually you could get away with couple extra. I never did this with any files I valued.

Most discs were rated to format to 80 tracks but some you could format with 81 or 82 and IIRC even 84 on some.

Then there was sectors, which was common to have 8, though again you could with better quality discs (quality did get better ahead of the standards) you could go with 9 sectors and higher - https://www-user.tu-chemnitz.de/~heha/basteln/PC/usbfloppy/f....

Of course, you could think of it as over-clocking - was no guarantee you get that extra capacity, and the early days - it was really luck, but like most things, quality improves and such avenues of formatting became more accessible.

Reply on news.ycombinator.com