Tech Flashback: iomega ZIP 100 vs 3M/Imation Superdisk LS-120 Showdown

A relatively long time ago, I reminisced about the iomega ZIP 100 and the 3M/Imation Superdisk LS-120 superfloppy systems. Unfortunately, at the time, I could only look at the performance of the ZIP 100, and then, only of the USB 1.1 bus-powered Pocket ZIP 100 drive. I had no Superdisk/LS-120 media, and the drivers for the Parallel Port version were completely AWOL.

Superdisk/LS-120 Media

Given that the LS-120 was never really that popular, I didn’t see any computer stores stocking it, and none of my friends ever had any. I still remember the blue body and special shaped silver coloured shutter quite fondly, like as in the LS-120 Wikipedia article.

Then, it dawned on me. eBay! It’s a great thing that eBay has almost practically anything, although for rare and old vintage devices, the prices can literally go through the roof. I was lucky that an Australian seller had some, still in wrapping, at an agreeable price (roughly $4 per disk). I bit the bullet, and a few days later …

Superdisk LS-120 in Package

… et voila! Three new Imation/3M LS-120 Superdisk cartridges, still in wrap. I hesitated to unwrap them given their condition, but I decided opening one wasn’t a problem. I had three after all!

Contents of Superdisk LS-120 Package

Uh what? Not a blue coloured disk!? Oh well, that’s new and unexpected. It’s still a Superdisk! Here’s a high quality scan of the insert with the warranty statement on the inside.

LS120cardoutside LS120cardinside

The disk itself is identically sized to a 3.5″ floppy disk and has the same holes as the HD disk. The shutter is given a unique shape as well as the label area, but the Superdisk can be inserted into a standard floppy drive (although, it will not work as an HD disk, even if you try, likely due to the coercivity of the media).



It also came with one extra label.


So, what’s so special about the disk that makes it a Superdisk? Well, it’s the laser servo technology that improves positioning accuracy to allow higher recording densities. How does this work? Well unfortunately, I wasn’t able to find it online – but now that I have the disk in hand, some of the mystery is unravelled.

If you take the disk and open the shutter and look at the top surface, it looks like a regular HD disk – it’s smooth.

LS120 Media Top Surface

This changes if you look at it from the bottom – you see a striped pattern which probably serves as the clocking information which allows the drive to compensate for variations in spindle speed.

LS-120 Laser Servo Marks

Here’s a better image, click for mega sized. I took care to optimize the lighting and aperture to get the resolution needed to resolve the lines right into the centre of the media. And yes, that’s a hard disk platter spacing ring holding the shutter open!

High Resolution Laser Servo LS-120

This doesn’t quite solve the question of how the system works for radial positioning. Maybe the width of the servo bands help to determine the radial position in an “analog” fashion.

Superdisk Drive

If you remember from last time, one of the troubles was the lack of a driver for the Parallel Port Superdisk drive. Inspired by the Wikipedia article, and the fact the enclosure was rattling with the front panel falling off, I disassembled the enclosure to find …

Superdisk External Parallel Port

… an IDE interface drive model LKM-F433-1 manufactured by Matsushita Kotobuki Electronics Industries Ltd. in Japan. Matsushita is probably better known as Panasonic. The drive is plastered in laser safety warning labels! This drive was attached to a Shuttle Technology EPAT PLUS and EPISA Parallel Bridge board, unfortunately, not much information about them anymore.

This was the finding I had hoped for. It should be a simple case of taking it out, and plugging it into a native IDE controller to get it to work, provided it’s ATAPI compliant.

LS120 drive front

As this drive was manufactured to go into an external enclosure, it has no front bezel. This is rather unfortunate, but not fatal.

LS120 drive rear

The rear of the drive features the IDE interface, a 4-pin berg power plug and a jumper block to configure the Master/Slave/CS setting.

LS120 Serial

The drive itself was manufactured November 1997 as can be seen in the serial barcode label attached to the side of the drive.

LS120 Underside

The underside of the drive is a rather messy layout – prone to shorting if placed carelessly onto a conductive surface. It’s already evident that there’s quite a bit more processing power – the flash chip for the firmware is visible, and a high quality spindle motor can be seen. Lets take a peek inside the drive – and try not to break anything.

Inside LS120 Drive

Inside, it looks similar to a regular floppy drive, aside from what appears to be a head preamp on the flex ribbon and an eject motor in the bottom corner. It’s also visible that the head is attached to a magnet which appears to pass through a hall sensor – this may be used to provide radial positioning.

LS120 Head

And here’s a not-so-good photo of the LS-120 head – it seems to have multiple gaps so as to be compatible with both regular HD disks and Superdisks.

I attached it to my spare AMD Sempron 3300+ Socket 754 system and it functioned perfectly. It was detected by Microsoft Windows XP SP3 as a High Capacity Floppy Drive and assigned a floppy drive letter.


The disk was recognized correctly with the stated capacity.


The drive sounds like someone rattling a bag of bearings all the time, or someone running water through a pipe continuously. It’s not that quiet, and it’s hardly confidence inspiring as it starts and stops randomly during continuous operations. It doesn’t have the whine that the ZIP 100 drives do, implying a lower media rotation speed – which will put it at a disadvantage when it comes to data transfer rate.

ZIP 100 Drives

My last article examined the performance of the USB 1.1 Pocket ZIP 100 drive. But what about the other interfaces? I owned an IDE/ATAPI unit, but that wasn’t hooked up at the time.

Since then, I’ve had a Parallel Port edition and a SCSI Port edition donated to me (which I disassembled here) – so now I have the whole complement.


The curious side of me always wanted to know – which ZIP drive is fastest? How does ZIP compare to Superdisk? I try to find out.

I used the HDTune read benchmark to gauge the read speed across the media. The Parallel Port edition was used with a port in EPP+ECP 1.9 mode, and the SCSI Port edition with an Adaptec AVA-2902 Fast SCSI Card. The IDE/ATAPI was connected to a VIA chipset port supporting ATA133, and the USB edition was connected to a VIA USB2.0 port. Unfortunately, as the Superdisk drive appears as a floppy drive, HDTune wouldn’t work with it.



ZIP 100 Pocket USB




ZIP 100 Parallel Port


For the Superdisk, I timed the duration of a full format (9 minutes 54 seconds) and divided the nominal size (120Mb) by the time to give an estimated rate of around 206kB/s.


I’ve managed to test the Superdisk drive, and play with some Superdisk media. I’ve also got a first hand glimpse into what makes the Superdisk Laser Servo system tick.

I’ve also been able to benchmark just how the systems compare – and it’s already clear that the Superdisk’s estimated transfer rate of 206kB/s is below 2x CD-ROM rate and is inferior to ZIP.

Across the different variants of ZIP drives, the IDE/ATAPI drive is the fastest, averaging about 1MB/s. The USB edition manages 0.7MB/s, and appears to be constrained by the USB 1.1 interface. Strangely, the SCSI edition which was always complemented for its speed only turned in 0.6MB/s – the limitation is not in the bus which would have run at least 5MB/s. As expected, the Parallel Port edition comes in dead last, although still respectably doing its best to cling to the upper half of 0.2MB/s, but eating all of the CPU to do so.

Looking at the graphs, it’s clear that the drive uses a zoned recording system and utilizes one side before the other, rather than utilizing both sides simultaneously.

None of this is really relevant anymore in 2013, although it’s interesting to academically study this in action.

About lui_gough

I'm a bit of a nut for electronics, computing, photography, radio, satellite and other technical hobbies. Click for more about me!
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4 Responses to Tech Flashback: iomega ZIP 100 vs 3M/Imation Superdisk LS-120 Showdown

  1. Sebastian says:

    Thank you for the article, benchmarks, and high resolution picture scans! Digital archeology and retro computing benefit from articles like this.

  2. rasz_pl says:

    Was just browsing wiki (reading about bootloaders) and landed on Laser-servo SuperDisk LS-120 page. Naturally I wanted to see how such a disk looks like and google image keeps you at the top 🙂

    What I didnt understand is why your pictures show a clear perpendicular pattern while documentation (and logic) dictates marks should be circular to help the Head stay on track. Removable disks are not fixed to the spindle (like hard drive disks) and wobble during each rotation, optical tracking corrects this wobble and enables >2K tracks per inch.

    Finally found this

    Turns out tracking marks are a series of lines ~2×40 micrometers arranged in circles spaced ~20 micrometers apart. I guess 2 micrometer thickness makes them appear as a color gradient instead of distinct objects. Maybe microscope would show a true pattern.

    • lui_gough says:

      At that kind of size, any sort of regularly spaced marks become a diffraction grating which, in essence, spreads out the light into its constituent components giving the “colour” effect and can make it hard to directly observe the structure. It’s the same reason why CDs and DVDs have a rainbow “band” when viewed directly from their underside. See

      An optical microscope would indeed help, but I don’t have one at my disposal at this time. More than that, in my experience, getting into ~1nm region with any level of sharpness requires ~100x magnification oil immersion objectives which would destroy the media. At 40x air, even though theoretically we can resolve 0.45um, it’s likely that it would appear quite blurry – and depending on whether the optical servo marks are visible at optical wavelengths, it might not be easy to see and require more advanced phase-detection methods. Of course, if someone has a microscope, I will love to see any images they might get :).

      Thanks, as always, for your very helpful digging and finding historical information on retro tech. Much appreciated, and definitely adds to the nostalgia.

      – Gough

  3. John says:

    Formatting a Superdisk LS-120 disk will take more time than a typical read or write operation. According to the website above, this is the LS-120 transfer rates.

    The SuperDisk™ drives ( an Imation trademark) are also known as LS-120 Drives.

    The internal models are made to fit into a standard floppy drive configuration.

    Typical characteristics

    Transfer rates : SuperDisk 565 KB/sec / Floppy Drive 62 KB/sec
    Avg. Seek Time : SuperDisk 70 msec / Floppy Drive 84 msec
    Track Density : SuperDisk 2490 tpi / Floppy Drive 135 tpi
    Number of Tracks : SuperDisk 1736 x 2 sides / Floppy Drive 80 x 2 sides
    Rotational Speed : SuperDisk 720 RPM / Floppy Drive 300 RPM

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