3M Diskette Reference Manual (1983) [pdf]

113 pointsposted 6 days ago
by susam

37 Comments

alentred

18 hours ago

Just recently I wanted to show my kids the 5.25" floppy disk - I had a small stack somewhere, but could not find it. I have finally found an 3½" floppy and have shown it to my kids (14 y.o. max). Evidently they never used such a thing, but I was genuinely surprised they didn't even know what it was. After a considerable amount of time one of my daughters hesitated but said something like: "Wasn't it like old USB stick thingy?". Given they have no USB stick either that's not bad, I guess. Then I proceeded to explain that a floppy disk is pictured on Save buttons - you just had to see their faces, it was a moment of the big revelation.

integricho

16 hours ago

Since they have never seen floppy disks before, why were you surprised that they did not recognize what they were?

vbezhenar

14 hours ago

Given that computers play a huge role in our lives, shouldn't we taught children some kind of history of computers? It's not that big anyway.

blueflow

15 hours ago

... have they seen Save buttons with the Floppy pictured on it, either?

ZuLuuuuuu

15 hours ago

Apparently 3M was a serious player back in the day on magnetic tapes and floppy diskettes. But today they are not present in a similar market (digital storage) at all.

I wonder what was it like to go through that timeframe, as the management and the employees, where the floppy disks were becoming obsolete. Did they purposefully took the decision to not pursue CD, flash memory market? Or was it just a shortsightedness of the management where they fell behind and eventually had to exit that market?

Of course 3M still managed to be successful and today it is one of the big market cap companies...

trollbridge

14 hours ago

They spun it off into Imation, as 3M’s specialty is coatings and chemicals. Storage no longer really uses those things

You could say that 3M doesn’t make the things you use every day; they make the things you use better.

hammock

8 hours ago

We call those “specialty chemicals” and it’s smaller volumes but much higher profit margins. Evonik (Germany) is another example.

Things like- not the asphalt shingle, not the granules on the asphalt shingles, but a COATING ON the granule on the asphalt shingle that provides weather protection.

Or, not the memory foam mattress, and not the liquid precursors that are combined to create the foam in the mattress, but an ADDITIVE to the precursors to the foam in the mattress which regulates/ensures a consistent size of foam bubbles during manufacture.

chiph

14 hours ago

3M was indeed a big player in those markets. I purchased both 5.25" and 3.5" 3M floppies and they were good quality and reliable.

I expect they left the market because of declining use and the entrance of much cheaper foreign manufacturers. I expect they didn't enter the flash memory market as they had no existing manufacturing base for them to build on. They would have had to rebrand another firm's chips and circuit boards.

proactivesvcs

20 hours ago

At 1,685,278 bytes this almost fits on within the hallowed 1.44 megabytes. Maybe the front and rear covers can be discarded?

Tuna-Fish

12 hours ago

A storage disk doesn't need ability to do random block writes, if you ditch that you can remove the sector gaps and put more sectors on the drive. The Microsoft DMF format and utility can put 1,720,320 bytes on a drive.

iberator

10 hours ago

Linux can do this as well.

manwithaplan

13 hours ago

It should fit on an DMF MF-2HD (standard double-sided, high density, 90 millimeters microfloppy formatted in Distribution Media Format, holding 1'720'320 bytes).

billfor

a day ago

It's interesting that the index hole is not on y-axis, if it is actually used to allow operations. I used all my SS 5.25" as DS just by flipping them I think, and they just worked. You weren't supposed to do that, but all the SS diskettes were coated on the other side, so you just fliped it and it would work, but it wouldn't be certified for that use case.

Tuna-Fish

12 hours ago

As soon as the motors used to spin drives were able to provide a once per rotation signal to replace the index hole, the hole was no longer used for anything. The detector and lamp used to detect the hole were more expensive than using a signal from the motor.

phire

3 hours ago

Motor rotation isn't quite enough, as it's not aligned to the sectors on the disk.

Drives which do skip indexing (Like Apple's Disk II) use the actual data on the disk for indexing. Each sector header has a track/sector/head ID, allowing the controller to know where it is on the disk without the need for indexing.

TBH, I'm not sure PC floppies even use the index pulse for anything other than formatting the disk. Once the disk is formatted, it's kind of redundant information. But it's required by the spec, forcing PC floppy drives to include the sensor.

teddyh

a day ago

From what I heard, the index hole was not used except by extremely old systems; i.e. IBM PCs never used them.

vincheezel

a day ago

That’s the first time I’ve ever read the measurement “microinches”

summa_tech

a day ago

You see it used sometimes for plating thickness, for instance gold plating on PCBs or connectors.

blueflow

15 hours ago

First steps with the metric system. About time!

userbinator

a day ago

1/1000th of a thou.

user

a day ago

[deleted]

amelius

12 hours ago

I'd be interested to read about the construction of floppy drive read/write heads.

commandersaki

a day ago

Back when things came with real documentation.

iberator

9 hours ago

>Refrain from smoking, eating, or drinking when handling a diskette to keep from contaminating the media surface.

sega_sai

13 hours ago

There is a surprising level of technical details on how the diskette works and how it was manufactured. You don't see that nowadays.

_trampeltier

12 hours ago

No, but back in the early computer days the manuals had been like that. Even for a keyboard you got the electric diagrams and thing like that.

herpessimplex10

21 hours ago

For all of computing eternity, the only person I've ever heard refer to it as a "diskette" is icon-lady Susan Kare.

jmorenoamor

14 hours ago

Diskette or disquete was a popular term in Spain for floppies, both 3 and 5 inches. In fact everyone called the disk drive "disquetera".

zkmon

21 hours ago

Includes a bit about manufacturing process and disk writing as well. Amazing!

glgrau

17 hours ago

such a clean documentation, that's actually inspiring

pilaf

a day ago

I get a 403 error. Any mirrors?

glxxyz

a day ago

Check the diskette for physical damage on the recording surface and at the hub centerhole.

BoorishBears

a day ago

The liner inside the jacket cartridge is a special-purpose, non-woven, highly-durable fabric... so I'd be surprised if there was any physical damage.

codeulike

10 hours ago

Oh there was definitely possibility of damage