Were floppy disks lubricated?

[Alex Eisenhut]

Was the surface of floppy disks lubricated? I found several references that suggest "yes" but never come out and say it. They would have used a molecule-thin layer (or thereabouts) of this

https://www.solvay.com/en/brands/fomblin-pfpe-lubricants

Specifically

"Fomblin® Z PFPE derivatives are well known lubricants for the Magnetic Recording Media industry where they are used as top lubricants on HD drive surfaces to prevent damage to the disk surface. "

That I can find references for, the lubricant is hugging the surface of the hard disk platter.

But floppy disk heads don't float, they directly clamp on to the surface of the disk. But they only spin at ~300RPM. I never quite understood how the surfaces don't wear out. I guess floppy disk drives don't spin all the time either.

Anyone have any knowledge to share?

[pcprogrammer]

But floppy disk heads don't float, they directly clamp on to the surface of the disk. But they only spin at ~300RPM. I never quite understood how the surfaces don't wear out. I guess floppy disk drives don't spin all the time either.

Was that not an issue with Commodore 64 floppy drives that they spun so much that they did wear out the floppies 

[xmris]

Not exactly lubricated, but there was Verbatim that once sold teflon coated floppies (Datalife Plus).

[iJoseph2]

I wonder if some (audio) minidiscs are lubricated with something?

I've bought some used minidiscs in the past and while in very good condition there were a few specs of dust on the platter... so I cleaned them before using with a cotton bud to remove the specs (I can't remember exactly what I did... I think I breathed on them then wiped with a dry cotton bud most of the time and IPA on stubborn specs)

What I noticed on the (I think) Sony and TDK discs - when wiping a kind of smudge would appear that would slowly "heal" over a minute or so .. a bit like I wiped off some lubricant and then the remainder would spread back to recover the area I just wiped. But never noticed this on other brands (Maxell/Sharp)

Apparently minidiscs are rated for 1 million writes, but going by this video I'm not convinced ...

At 9m49s

[Zoli]

The PC floppy disks spins as long as the access LED is on, AFAIK.
Heads: core made out of ferrite, similar to the VHS fly heads.

[AndyBeez]

The only lubricant I ever noted in a FDD system was grease on the read head stepper arm. Which was something you did not want going anywhere else!

The floppy disk itself was sandwiched between two sheets of soft synthetic 'felt' which ensured the FDD would spin without the need for lubrication. The fibres also acted as a dust and pollen catcher. Attached, inside the shell of a 3M branded 3.5 inch floppy. The other side has the same profile in mirror image. The gap is for the read head. It also makes sense that this sheet has anti static properties.

FDD Cleaning Disks were a disc made from this material spun round a few times, with a few drops of 'specialist head cleaning fluid' applied. Weak IPA probably? Floppy disks did wear out, with the dreaded BAD DISK message. But that was only likley if you were a student who used the same FDD term on term. By the late 90s, most computer and business people had accumulate dozens of FDDs; most of which went extinct as the USB memory stick arrived.

[helius]

Yes, there is a dry film lubricant to keep the heads sliding smoothly over the disk surface. All magnetic media is lubricated in one way or another, including audio tapes.

[Psi]

You just have to be careful that you don't lubricate them too much, or this will  happen on eject.

[Alex Eisenhut]

I'm asking because I started reading a textbook on nanotribology, the study of surfaces and friction. I was reading that because people claim mold grows on the surface of floppy discs.

That's fine, but I don't know of many molds that wait 30 years before eating perfluorinated compounds especially in such thin layers... 

But there are some disk surfaces with various splotches and discolored areas, I wonder if that's just the pattern of the felt liner imprinted on the surface, or some sort of delamination.

Or is there a specific floppy disk mold that eats polyester ... reeeeeaaaaally slooooooowly?

I'm not disputing the fact that people report success in getting previously unreadable disks to read after a cleaning. I'm just wondering what the problem is with some disks.

Could it be some long term interaction like when you store PVC cables on a ABS computer and the cable dissolves the ABS over time?

[T3sl4co1l]

I'm asking because I started reading a textbook on nanotribology, the study of surfaces and friction. I was reading that because people claim mold grows on the surface of floppy discs.

That's fine, but I don't know of many molds that wait 30 years before eating perfluorinated compounds especially in such thin layers... 

But there are some disk surfaces with various splotches and discolored areas, I wonder if that's just the pattern of the felt liner imprinted on the surface, or some sort of delamination.

Or is there a specific floppy disk mold that eats polyester ... reeeeeaaaaally slooooooowly?

I'm not disputing the fact that people report success in getting previously unreadable disks to read after a cleaning. I'm just wondering what the problem is with some disks.

Could it be some long term interaction like when you store PVC cables on a ABS computer and the cable dissolves the ABS over time?

Not to mention mold on camera lenses and other seemingly inert, inhospitable, or certainly not nutritious, surfaces.  I'm guessing something like, the collected dust happens to be edible?  And then the growth pattern is just wherever the hyphae wanted to go.

Tim

[james_s]

Not to mention mold on camera lenses and other seemingly inert, inhospitable, or certainly not nutritious, surfaces.  I'm guessing something like, the collected dust happens to be edible?  And then the growth pattern is just wherever the hyphae wanted to go.

Doesn't mold photosynthesize? I had assumed it just found a surface that it could stick to, perhaps attracted by condensed moisture. I never bothered to look into it though.

[AndyBeez]

Biofilm, it's everywhere and on everything.

https://en.m.wikipedia.org/wiki/Biofilm

[T3sl4co1l]

No, although lichen does. But that's a symbiote between fungus and algae (and maybe something else, it's weird).

Tim

[rsjsouza]

I'm asking because I started reading a textbook on nanotribology, the study of surfaces and friction. I was reading that because people claim mold grows on the surface of floppy discs.

IME I have seen a number of 5-¹/₄ and 3-¹/₂ with life growth on its media. We called it "mold", but it could be lichens or anything, really (I never got deep into the matter).

For the 3-¹/₂ floppies, photosynthetic life forms wouldn't subsist as the media is enclosed. However, I have seen these floppies get rust together with the "mold" (the spinning axis is metal). The 5-¹/₄ is entirely polymeric.

[helius]

Camera lenses may be more nutritious than commonly believed: the clear resin bonding elements of optical glass often contains balsam (tree sap), and the anti-reflection coatings contain various polymers.

Reminds me of the Coneheads skits: "MMM, we love your delicious plastic resins!"

But fungi have been discovered that eat all kinds of seemingly inert materials including metals and ceramics.

With magnetic media like floppy disks, there is a ferrite or other magnetic layer glue-bonded onto a base, and overcoated with a protective layer that may also act as a dry lubricant. Over time one of the failures that happens is depolymerization of the glue, leading to shedding of the magnetic layer when the head rubs against it. This is why "baking" is commonly recommended for old tapes: heating the binder can cause it to re-cure to a limited extent, which makes data recovery more likely.

The fabric pad around a floppy disk is a mixed blessing; it does catch dust and debris that could get between the disk and the heads, but that trapped debris also never goes anywhere, and is constantly rubbing against the disk. The floppy envelope is also not very well sealed. Yes, 3.5" disks have the sliding cover, but it leaves the area around the hub exposed, and perhaps worse it encourages users to leave their disks lying around without sleeves. After 1990 or so, manufacturers even stopped shipping them in individual plastic sleeves, which made it easier to pick up dust.