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single sided 3.5 floppy

Twospruces

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I recently saw a box of Fujifilm MF1DD single sided 3.5 inch floppy diskettes.

Were these really uncommon? I can't find much reference to 3.5 disk drives being single sided?
 
first macintosh (128kb and 512kb) and the apple lisa 2 had single sided 400kb 3.5" floppy disks. Sony invented the 3.5" floppy and it was thier drive that was single sided.
 
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First one was probably the Sony SMC-70, about 2 years before the Mac. https://en.wikipedia.org/wiki/Sony_SMC-70
Next major one was the HPIB drive. The success of its use at HP helped create the secret push to replace the Twiggy. http://www.hpmuseum.net/display_item.php?hw=288

I am not sure what was the first machine with a Shugart interface 3.5" single sided drive. I am fairly certain that a machine from 1984 did it before the IBM JX in late 1984. The Atari ST (1985) got most of the attention for single sided 3.5" drives. How could I forget the Gavilan? http://oldcomputers.net/gavilan.html

There was also the 40 track 3.5" drives which were made by Brother and probably best known around here as the basis for the Tandy PDD. I can't find a date on when Brother introduced the line.
 
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Brother WPs with the 120K or 240K 3.5" disks are single-sided.

Sony 0A-30, ca. 1981 single-sided 3.5" DD, spinning at 600 RPM with head-load solenoid.
 
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They are uncommon. Definitely a box of disks you want to hold on to, just as this thread shows.

Speaking of which I need to determine which of my 8" disks are single or double sided. Is it the Double has two index holes? I forget I need to look that up and categorize them.
 
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I have a bunch of random single-sided 3.5" disks as well. Thing is, they format just fine as double sided. I assume the 2nd side just failed the quality test in the factory and such disks were then sold as single-sided for systems that used them. They are coated on both sides.

Same is true for all single-sided 5.25" disks I own, too.
 

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8" SS disks will work as DS if a hole is punched in the appropriate spot.

Could be useful depending on how much of have of which. I do want to fix my two QUME double sided drives this spring and I figure that cabinet might make a good Disk making station if its up and working.
 
So you never had disks with mold spots that you had to clean?

This is a very common issue. So common that you can find 3d-printable helpers for most disk formats (to keep the shutter open and a knob to rotate the disk).
 
Yes, Unfortunately I keep coming across floppies (3.5" and 5.25") with mold or dirt on the disk surface in my pickups.
 
I guess that I've been fortunate... Have processed mold-encrusted 1/2" tapes, however. There were also 3.5" floppies without the return spring--the shutter was manually operated. You can accomplish the same thing by removing the return spring in a regular 3.5" diskette housing.
 
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