TOF : misinformation

On TOF, someone posted that in the past they’d had a S-100 computer with DSDD 12" Floppy disks with a capacity of 1.2meg each.

This is incorrect, since a 12" floppy disk was never made.
In the time frame (late 70’s) there was an 8" DSDD disk (Shugart 850) that was 1.2meg

Floppy Disks came in 8", 5.25", 3.5" with some odd 2.0, 3.0 and 2.5" ones

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misremembering I suppose ?

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I recall using 7 or 7.5 inch floppies in the “console” of a Digital VAX 11/780. The floppy was needed to start an embedded LSI-11 computer which functioned as the VAX console. I never actually measured the floppy, could have been close to 8 inches. Also don’t recall the capacity.

I’ve heard about 15 inch floppies, but never actually seen one.

I have an old 5-1/4" floppy disk from back in the old days. Here is a picture:


This might have been used on a Commodore 64?

This is a “double sided” 5.25" floppy.

I recall making the squared hole to write on the other side on my Apple //c… (143KB).
Sometimes later, I hears about 1.2MB 5.25" for DOS computers…

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The biggest floppies I’ve ever used were 8"
Dont think they were double sided but I’m not 100% sure

That said Wikipedia, the source of all knowledge nowadays, doesnt list any 12" floppy

i think i saw a 8" floppy in a bank in singapore. they have a big IBM computer and use the big floppy

I used 8" floppies extensively in the early '80s, in National Semiconductor’s development system for their COP400 4-bit microcontrollers.

I’m not disputing the fact that 8" floppy disks existed… I am disputing that a 12" one ever did

I have used 3.5, 5.25, and 8, and know that other sizes <8" were rare, but existed.

I’ve used a lot of hardware over the past nearly 4 decades
Never seen a size of floppy larger than 8"


The round thing above the “computer” is a mass storage object. What it is and its capacity is unknow to me.

I worked at Volvo Penta France with this during 5 years (spare parts stock / acounting, etc.) in the early 80s.

Looking at that reminded of the first desktop machine I programed in BASIC back in the mid 70’s:

Speaking about storage,That bay on the right is a RANDOM ACCESS cassette drive. The cassettes looked the same as the audio cassettes of that day to me. And it was relatively fast! You would not believe what that system cost back then! I used it when I was working at an Army Research Center while in college.

When I got my first home machine a few years later with a cassette drive I was so disappointed with the drive performance compared to that of that HP “calculator” !