three-inch drives in other systems

Started by angelcaio, 10:56, 23 February 22

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I open this thread just to share a curiosity.
I only knew Amstrad and Tatung as systems that used the Hitachi 3-inch format.
But I was surprised to find this ad in Byte magazine from March 1983 (  ) announcing a three-inch drive for the IBM PC.

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The Sega SC3000 had a companion unit with a 3" drive.

On the silly side of things, you can connect a FD-1 disk drive to a Dragon disk controller and it will work  :)


The Spectrum +3 would be another notable example (although that's basically Amstrad again)

Though people forget that back in the early to mid 80s the choice of disk drive wasn't really as clear cut. It was really IBM "blessing" the 3.5" format, by including it on their PCs, that subsequently led to it's dominance and making most of the other variations obsolete.


Check out this beauty for the Famicom. The engraved brand was tested by the disk drive, to ensure it was an original disk.


The company Amdek made a dual 3in Disk drive for the Atari XL/XE too.



The drive is boasting 1 megabyte unformatted capacity. That must be across two disks surely?
An expanding array of hardware available at (and issue 4 of CPC Fanzine!)


"unformatted capacity" is a marketing con, the value is entirely unverifiable (after all, you can't use the disc until it's formatted) and therefore essentially meaningless.


As I know first was Yamaha with FDD for own MSX, and Yamaha Midi keyboard with build 3" FDD.
I can't find picture. :(

Sega SF-7000 for Sega SC-3000, it Master System + more RAM & ROM with Basic.

Timex FDD 3000, could work as seperate CPM terminal with keyboard, or as FDD for Timex and Spectrum computers. There was no rubber belt. Two drives version only.

Or little cheaper version FDD3, with only one drive and less RAM, no CPM option.

Unipolbrit 2086 with huge FDD 3". size like old 1541 for C64. It has two ports for Kempston Joystick.
Timex and Unipolbrit had 164K per side with catalogs, later version 640K per disc.

Bosman 8, CPM with 512K, and one 5.25" drive option, or two 3" drives, on picture.

Tatung Einstein TC1 and 256, with Power Supply inside monitor before Amstrad CPC.

Oric Atmos and two kind 3" FDD, Jasmin and Oric Microdisc.

Amdek with Amdisk III (1 or 2 drive version), (180K or 720K drives), with interface for many different computers those times like IBM PC, Tandy TRS-80 and CoCo, AppleII, Atari 800/XL, Thomson...

And all of them before Amstrad with CPC, PCW and ZX+3. :)
In STARS, TREK is better than WARS.


@ZbyniuR I think that you have listed all of them. 8)
About the SC-3000, it is a SC-1000 hardware, not Master System.
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)


Some of the early sampled electric pianos used 3" discs to hold the samples IIRC, but I think they quickly moved to 3.5" discs.


Quote from: robcfg on 19:50, 23 February 22The Sega SC3000 had a companion unit with a 3" drive.

On the silly side of things, you can connect a FD-1 disk drive to a Dragon disk controller and it will work  :)
I think Shugart was standardised in the 70s when people were shifting from 8" discs to 5.25" discs, but now I've written that I wonder if it was actually earlier as I think most 8" drives (if you can actually find one) will work with a controller like the 765.

Then again, it's hard to get a much simpler interface. The only important pins for any drive are:

MOTOR control (out)
TRACK step (out) and direction (out), track 0 sense (in)
READ data (in)
WRITE enable (out) and data (out)
SENSE for the optical detector that marked the start of the track (in)

Some systems like Apple ][ needed motor speed control too. But they were the exception.

The hole sense was optional on the Amiga because by then, they'd realised they could detect the start of track from just the sync markers at the start of each sector and read the entire track and just write out an entire track at once and not care where it started.

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