[HN Gopher] 3M Diskette Reference Manual (1983) [pdf]
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       3M Diskette Reference Manual (1983) [pdf]
        
       Author : susam
       Score  : 110 points
       Date   : 2025-10-27 23:44 UTC (5 days ago)
        
 (HTM) web link (retrocmp.de)
 (TXT) w3m dump (retrocmp.de)
        
       | mrblampo wrote:
       | This is pretty cool
        
       | pilaf wrote:
       | I get a 403 error. Any mirrors?
        
         | glxxyz wrote:
         | Check the diskette for physical damage on the recording surface
         | and at the hub centerhole.
        
           | BoorishBears wrote:
           | 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 wrote:
             | Oh there was definitely possibility of damage
        
         | Brian_K_White wrote:
         | worked for me so idk
        
         | kalleboo wrote:
         | Same here. Even going directly to the front page it's a 403.
         | 
         | Looks like it's on the Internet Archive
         | https://web.archive.org/web/20241104214425/https://retrocmp....
        
       | vincheezel wrote:
       | That's the first time I've ever read the measurement
       | "microinches"
        
         | summa_tech wrote:
         | You see it used sometimes for plating thickness, for instance
         | gold plating on PCBs or connectors.
        
         | userbinator wrote:
         | 1/1000th of a thou.
        
         | blueflow wrote:
         | First steps with the metric system. About time!
        
       | commandersaki wrote:
       | Back when things came with real documentation.
        
       | billfor wrote:
       | 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.
        
         | teddyh wrote:
         | From what I heard, the index hole was not used except by
         | _extremely_ old systems; i.e. IBM PCs _never_ used them.
        
         | Tuna-Fish wrote:
         | 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.
        
       | zkmon wrote:
       | Includes a bit about manufacturing process and disk writing as
       | well. Amazing!
        
       | herpessimplex10 wrote:
       | For all of computing eternity, the only person I've ever heard
       | refer to it as a "diskette" is icon-lady Susan Kare.
        
         | jmorenoamor wrote:
         | Diskette or disquete was a popular term in Spain for floppies,
         | both 3 and 5 inches. In fact everyone called the disk drive
         | "disquetera".
        
       | proactivesvcs wrote:
       | At 1,685,278 bytes this almost fits on within the hallowed 1.44
       | megabytes. Maybe the front and rear covers can be discarded?
        
         | manwithaplan wrote:
         | 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).
        
         | Tuna-Fish wrote:
         | 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 wrote:
           | Linux can do this as well.
        
       | alentred wrote:
       | 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 31/2" 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 wrote:
         | Since they have never seen floppy disks before, why were you
         | surprised that they did not recognize what they were?
        
         | blueflow wrote:
         | ... have they seen Save buttons with the Floppy pictured on it,
         | either?
        
         | vbezhenar wrote:
         | 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.
        
       | glgrau wrote:
       | such a clean documentation, that's actually inspiring
        
       | ZuLuuuuuu wrote:
       | 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 wrote:
         | 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 wrote:
           | 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 wrote:
         | 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.
        
       | sega_sai wrote:
       | 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 wrote:
         | 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.
        
       | amelius wrote:
       | I'd be interested to read about the construction of floppy drive
       | read/write heads.
        
       | iberator wrote:
       | >Refrain from smoking, eating, or drinking when handling a
       | diskette to keep from contaminating the media surface.
        
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       (page generated 2025-11-02 23:01 UTC)