The 21 MB Floptical 3½-inch disk

Floptical refers to a type of floppy disk drive that combines magnetic and optical technologies to store data on media similar to standard 3½-inch floppy disks. The name is a portmanteau of the words "floppy" and "optical". It refers specifically to one brand of drive and disk system, but is also used more generically to refer to any system using similar techniques.

The original Floptical technology was introduced late in 1991 by Insite Peripherals, a venture funded company set up by Jim Adkisson, one of the key engineers behind the original 5¼-inch floppy disk drive development at Shugart Associates in 1976. The main shareholders were Maxell, Iomega and 3M.

Technical aspects

The technology involves reading and writing data magnetically, while optically aligning the read/write head in the drive using grooves in the disk being sensed by an infrared LED and sensor (a form of visual servo). The magnetic head touches the recording surface, as it does in a normal floppy drive. The optical servo tracks allow for an increase in the tracking precision of the magnetic head, from the usual 135 tracks per inch to 1,250 tracks per inch. Floptical disks provide 21 MB of storage. The drive has a second set of read/write heads so that it can read from and write to standard 720 kB and 1.44 MB (1,440 KiB) disks as well.

To allow for a high degree of compatibility with existing SCSI host adapters, Floptical drives were designed to work as a standard floppy disk drive, and not as a removable hard disk. To ensure this, a "write lockout" feature was added in the firmware. This effectively inhibits writing (including any kind of formatting) of the media. It is possible to unlock the drive by issuing a SCSI Mode Sense Command, 1A 00 20 02 A0. It is unclear how much of a problem this is, and Insite also issued EPROMs where this "feature" was not present.

At least two models were produced, one with a manual lever that mechanically ejected the disc from the drive, and another with a small pinhole into which a paperclip can be inserted, in case the device rejected or ignored SCSI eject commands.

Technical specifications

Unformatted 25 MB
Formatted 20,385 kB
Rotational speed 720 RPM
Track density 1250 TPI
Recording density 23980 BPI (RLL)
Transfer from disk 1.6 Mb/s
Buffer transfer rate 2 MB/s
Average seek time 65 ms
Settle time 15 ms
Motor start time 750 ms
Number of heads 2
Cylinders 755
Sectors per track 27
Sector size 256, 512, or 1024 bytes (set at format time)
Interface SCSI

Market performance

Insite licensed the floptical technology to a number of companies, including Matsushita, Iomega, Maxell/Hitachi and others. A number of these companies later formed the Floptical Technology Association, or FTA, to try to have the format adopted as a replacement of standard floppy disks.

Around 70,000 Insite flopticals are believed to have been sold worldwide in the product’s lifetime. Silicon Graphics used them in their SGI Indigo and SGI Indy series of computer workstations. It was also reported that Commodore International had selected the Insite Floptical for its Amiga 3000.[1] However this did not take place, and while Flopticals were installed in many Amiga systems, they were sold by either Insite, TTR Development or Digital Micronics (DMI), and not bundled by Commodore.

The product has lingering quality and reliability issues, and is generally much slower than other technologies such as the Iomega Zip. In fact, while Iomega licensed the floptical technology as early as 1989 and produced a compatible drive known as the Insider, they later dropped it to focus on the Zip system. Zip would go on to sell into the tens of millions.

A number of other companies also introduced non-compatible floptical-like systems. Most popular of these, by far, was the Imation LS‑120 SuperDisk. The LS-120 stores 120 MB of data while retaining the ability to work with normal 3½-inch disks, interfacing as a standard floppy for better compatibility. There was serious consideration that the LS-120 would succeed where the Floptical failed and replace the standard floppy disk outright, but the rapid introduction of writable CD-ROM systems in the early 2000s made the market disappear. Sony also tried their own floptical-based format, the Sony HiFD, but quality control problems ruined its reputation. A smaller competitor is the almost unknown Caleb UHD144.

Operating system support

Support of Floptical drives is present in all Microsoft Windows NT operating systems up to MS Windows 2000, where it figures as 20.8 MB drive format option in the FORMAT command options. The FORMAT command in MS Windows XP and newer MS Windows operating systems lacks support of the Floptical drive.[2] Floptical support exists in SCO OpenServer as well. SCSI-equipped Macintosh computers could boot from a Mac operating system installed on a floptical; a formatting utility application was provided to erase and format floptical disks. Likewise, Silicon Graphics's IRIX operating system includes floptical support.

See also


  1. The flop's a hit
  2. Lack of Floptical support in Windows XP, Microsoft, retrieved 12 September 2007.

External links

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