View source for SuperDisk

{{short description|Storage medium from Imation}}
{{hatnote|For another use, see [[MSD Super Disk]]. For the Super NES CD-ROM, see [[Super Disc]]. "LS120" redirects here; for another use, see [[Dot matrix printer#DEC's dot matrix printers]]. Not to be confused with Apple's [[SuperDrive]].}}
{{Use dmy dates|date=January 2022|cs1-dates=y}}
{{Use list-defined references|date=January 2022}}
[[File:Imation SD-USB-M3 SuperDisk Drive.jpg|thumb|Imation SuperDisk drive]]
[[File:Super Disk 120MB 9116.jpg|thumb|An LS-120 disk]]

The '''SuperDisk LS-120''' is a high-speed, high-capacity alternative to the 90&nbsp;mm (3.5&nbsp;in), 1.44&nbsp;[[Megabyte|MB]] [[floppy disk]]. The SuperDisk hardware was created by [[3M]]'s storage products group [[Imation]] in 1996,<ref name="NYT_1996"/> with manufacturing chiefly by [[Panasonic|Matsushita]].

The SuperDisk had little success in North America; with [[Compaq]], [[Gateway, Inc.|Gateway]] and [[Dell]] being three of only a few [[Original equipment manufacturer|OEM]]s who supported it. It was more successful in Asia and Australia, where the majority of second-generation '''SuperDisk LS-240''' drives and disks were released.  There was one model of LS-240 drive released in North America, by QPS. SuperDisk worldwide ceased manufacturing in 2003.

==History==
The design of the SuperDisk system came from an early 1990s project at [[Iomega]]. It is one of the last examples of [[floptical]] technology, where [[laser]]s are used to guide a magnetic head which is much smaller than those used in traditional floppy disk drives. Iomega orphaned the project around the time they decided to release the [[Zip drive]] in 1994. The idea eventually ended up at 3M, where the concept was refined and the design was licensed to established floppy drive makers [[Panasonic|Matsushita]] and [[Mitsubishi Electric|Mitsubishi]]. Other companies involved in the development of SuperDisk include Compaq and OR Technology.{{fact|date=June 2024}}

Matsushita continued development of the technology and released the LS-240. It has double the capacity of the LS-120 and the added feature of being able to [[Superformatting|format regular floppy disks to 32&nbsp;MB capacity]].<ref name="Sherriff_2000"/> However, this higher density comes at a price – the entire disk must be rewritten any time a change is made, much like early [[CD-RW]] media.

A SuperDisk drive was used in two Panasonic [[digital camera]]s, the PV-SD4090<ref name="Panasonic_SD4090"/> and PV-SD5000,<ref name="Panasonic_SD5000"/> which allowed them to use both SuperDisk (LS-120) and 3.5″ floppy disks as the [[Digital camera memory media|memory media]].{{fact|date=June 2024}}

==Technical information <span class="anchor" id="SD120MB"></span><span class="anchor" id="SD240MB"></span><span class="anchor" id="FD32MB"></span>==
[[File:SuperDisk Mac - USB to IDE adapter.jpg|thumb|Circuit components of the external [[USB]] SuperDisk for Macintosh. The drive itself is the same size as a standard 3.5″ floppy drive, but uses an [[advanced technology attachment|ATA]] interface. On the right is the USB-to-ATA adapter, which plugs into an intermediate fan-out and [[power supply]] [[daughterboard]] that is inside the rear of the Mac drive's casing. This particular drive cannot function using USB power alone.]]
[[File:SuperDisk voice coil and eject.svg|thumb|This shows the technology of the SuperDisk drive. Two voice coil servomotors move the drive heads precisely across the disk surface.<br />'''BLUE''' - The main servo with a large coil provides the primary force to move the head mechanism.<br />'''YELLOW''' - A secondary smaller coil primarily acts to keep the head mechanism aligned parallel with the disk surface. <br />'''RED''' - The drive eject motor allows the disk to be under computer control so that it normally will not eject until the computer has completed its read or writing tasks.]]

The SuperDisk's format was designed to supersede the floppy disk with its higher-capacity media that imitated the ubiquitous format with its own 120&nbsp;MB (and later 240&nbsp;MB) disk storage while the SuperDisk drive itself was backwards compatible with 1.44&nbsp;MB and 720&nbsp;KB floppy formats ([[Modified Frequency Modulation|MFM]]). Superdisk drives read and write faster to these sorts of disks than conventional 1.44&nbsp;MB or 720&nbsp;KB floppy drives.{{fact|date=June 2024}}

The newer LS-240 drives also have the ability to read and write regular 1.44&nbsp;MB floppies at much higher densities in a format called "FD32MB". Described in the [[WinHelp|help file]] for the SuperWriter32 application included with the driver package, the increase of capacity for FD32MB is achieved through the use of [[shingled magnetic recording]] (SMR) to reduce track pitch to 18.8μm from the standard 187.5μm, allowing 777 tracks per side. This is combined with linear recording density improvements enabling 36-53 sectors per track through [[partial-response maximum-likelihood]] and [[zone bit recording]].{{fact|date=June 2024}}

The true capacity of these "SD120MB" drives<ref name="LKML_2000"/> is 120.375 [[Mebibyte|MiB]] aka 126.22&nbsp;MB ([[FAT16B]] with logical geometry 963/8/32 [[Cylinder-Head-Sector|CHS]] × 512 bytes). The "SD240MB" drives have a capacity of 229.25&nbsp;MiB aka 240.39&nbsp;MB ([[FAT16B]] with logical geometry 262/32/56 CHS × 512 bytes). 1.44&nbsp;MB HD floppies formatted to 32&nbsp;MB as "FD32MB" ([[FAT16B]] with logical geometry 1024/2/32 CHS × 512 bytes) in the LS-240 show a dummy [[FAT12]] file system (with logical geometries 160/2/9 or 80/2/18) when inserted into a normal floppy drive.{{fact|date=June 2024}}

SuperDisk drives have been sold in [[parallel port]], [[USB]], [[Advanced Technology Attachment|ATAPI]] and [[Parallel SCSI|SCSI]] variants. All drives can read and write 1.44&nbsp;MB and 720&nbsp;[[Kibibyte|KiB]] [[Modified Frequency Modulation|MFM]] floppies, as used on PCs, [[Apple Macintosh]]es (High Density format only, see below), and many [[workstation]]s. 2.88&nbsp;MB floppy formats are not supported.{{fact|date=June 2024}}

Imation also released a version of the SuperDisk with "Secured Encryption Technology", which uses [[Blowfish (cipher)|Blowfish]] with a 64-bit key to encrypt the contents.{{fact|date=June 2024}}

Under [[Windows XP]]'s <code>sfloppy.sys</code> [[Device driver|driver]], a USB SuperDisk drive will appear as a 3.5″ floppy disk drive, receiving either the drive letter A: (if there is no floppy in the machine) or B: (if there already is one). This enables use by software that expects a floppy drive when 1.44&nbsp;MB or 720&nbsp;KB disks are inserted. 120&nbsp;MB and 240&nbsp;MB disks are also accessed via A: or B:.<ref name="Gough_2013"/>

<gallery>
File:Imation Super Disk LS-120.jpg|Imation SuperDisk LS-120 diskettes
File:Matsushita LKM-F934-1 SuperDisk.jpg|Internal [[Drive bay#3.5-inch|3.5″]] SuperDisk drive
File:PIC 0856 SuperDisk.JPG|External [[parallel port]] SuperDisk drive
File:Super Disk 120MB 9111.jpg|SuperDisk 120MB diskettes in packaging
File:Super Disk 120MB 9129.jpg|SuperDisk 120MB diskette disassembly
</gallery>

==Criticism and obsolescence==
Older 800KB and 400KB [[Mac (computer)|Macintosh]] floppies, using [[Group coded recording|GCR]], did not work with a SuperDisk drive. These disks could be used in a SuperDisk drive only if formatted to PC 720&nbsp;KB MFM format. Note that almost no USB floppy drives supported Mac GCR floppies.{{fact|date=June 2024}}

The biggest hurdle standing in the way of success was that Iomega's [[Zip drive]] had been out for three years when SuperDisk had been released. Zip had enough popularity to leave the public mostly uninterested in SuperDisk, despite its superior design and its compatibility with the standard floppy disk.{{fact|date=June 2024}}

By 2000, the entire removable magnetic disk category was finally obsoleted by the falling prices of [[CD-R]] and [[CD-RW]] drives, and later on [[solid-state drive|solid-state]] ([[USB flash drive]]s or USB keydrives). Over the next few years, SuperDisk was quietly discontinued, even in areas where it was popular. Today, disks are very hard to find.{{fact|date=June 2024}}

==Practicality==
The USB models were quite popular for debugging and installing servers that did not have a CD drive available. They could both store massive numbers of drivers for installation purposes as well as be used to run live operating systems, such as [[ReactOS]], which amounts to 150&nbsp;MB.{{fact|date=June 2024}}

==See also==
{{Portal|Engineering}}
* [[Caleb UHD144]]
* [[IBM Extended Density Format]], technically unrelated special format for traditional HD floppy controllers, also providing a mini file system containing a [[README]] file similar to the LS-240's FD32M format.
* [[Sony HiFD]]

==References==
{{reflist|refs=
<ref name="Sherriff_2000">{{cite web |url=https://www.theregister.co.uk/2000/10/23/32mb_on_a_humble_floppy/ |title=32MB on a humble floppy |first1=Lucy |last1=Sherriff |date=2000-10-23 |website=[[The Register]] |access-date=2017-08-06}}</ref>
<ref name="Panasonic_SD4090">{{cite web |url=http://ftp.panasonic.com/camera/om/pv-ds4090_en_om.pdf |date= |title=Digital Camera Operating Instructions Model No. PV-SD4090 |publisher=[[Panasonic]] |access-date=2017-08-06}}</ref>
<ref name="Panasonic_SD5000">{{cite web |url=http://ftp.panasonic.com/camera/om/pv-ds5000_en_om.pdf |date= |title=Digital Camera Operating Instructions Model No. PV-SD5000 |publisher=[[Panasonic]] |access-date=2017-08-06}}</ref>
<ref name="LKML_2000">{{cite web |url=https://lkml.org/lkml/2000/3/12/171 |date= |title=LKML Boot Messages}}</ref>
<ref name="Gough_2013">{{cite web |url=http://goughlui.com/?p=3173 |title=Tech Flashback: iomega ZIP 100 vs 3M/Imation Superdisk LS-120 Showdown |author-last=Lui |author-first=Gough |date=2013-05-02 |access-date=2013-06-24}}</ref>
<ref name="NYT_1996">{{cite web |url= https://www.nytimes.com/1996/03/11/business/3m-chases-the-dream-of-building-a-better-disk.html |date= |title=3M Chases the Dream of Building a Better Disk}}</ref>
}}

== External links ==
* {{Commons category inline}}

{{DEFAULTSORT:Superdisk}}
[[Category:Floppy disk drives]]