Canb2016: Special 1 – LS-120 & Zip250 Drives, LS-240 Disk & Benchmarks

In the last post, I alluded to some special postings related to my Canberra trip. Aside from the conference and roaming around, I was contacted by a reader who wished to offer me a few items as they thought I would be interested in it. Because of their generosity, there will be a few special posts to cover the haul.

LS-120 Drive

I previously mentioned the Imation/3M Superdisk system, otherwise known as the LS-120, in a previous posting and I even did some preliminary benchmarks.

Similar to my situation, this drive came from a Superdisk external parallel port unit. Opening the unit and removing the drive reveals an ATAPI Removable Disk unit with an IDE interface and a floppy-disk style molex power connector which can be used directly connected to a motherboard IDE port.

I did try using the unit on a Sil0680 controller without any luck – it was detected by its firmware, but not by the drivers in Windows 7 … so it always pays to have some legacy systems maintained on hand to deal with such units.

Because of its shucked nature, it doesn’t have a front bezel, but that doesn’t stop it from being functional.

This unit is dated October 1997, making it one month older than the unit I previously tested.

That being said, the unit is also an MKE unit of revision C, Made in Japan.

The rear has an unshrouded connector, although it is keyed. The power connector lost a little plastic and the outer shell was a little compressed around the front, but the drive otherwise survived relatively unscathed.

The mechanism is identical to the other drive I have, but I still had to peer inside just to make sure (and to make sure it’s clean and ready to be tested). It was also a chance to use my better gear to get some better shots of some of the internal components.

For example, this bar magnet on the side attached to the sled with a hall-effect sensor on the side is likely to be used to provide coarse positioning information for use with backwards-compatible mode (DS HD/DD floppy disks).

I got a much closer look at the two-head arrangement on the sled.

On the left side of the head assembly, the head coils are wound. It all looks good, so I tested the drive by plugging it into the motherboard IDE port of an old machine that had Windows XP installed, and it came right up along with my test LS-120 disk.

LS-240 Disk

The Superdisk system wasn’t content to stagnate at 120Mb per disk. After all, iomega pushed Zip to 250Mb per cartridge, so they fired right back with a doubling of capacity to 240Mb. LS-240 drives also had a second trick up their sleeves – they were able to format regular DS-HD floppies up to 32Mb, although fairly slowly and in a write once manner (if I recall correctly). Unfortunately, I never had an LS-240 drive, and one has never come across my bench.

However, two brand new LS-240 disks were part of the haul. Judging from the packaging, these were intended for the Japanese market. Each disk comes in its own plastic jewel case, as per the 120Mb disks.

The disk bears resemblance to a regular DSHD disk, with the exception of the shutter and label cut-out which is distinctly different, along with the ribs. However, that being said, externally the disk has the same outline as the LS-120 disk. You might wonder, what happens if you stick an LS-240 disk into an LS-120 drive? I tried, and it just results in a very confused drive trying to read the disk over and over without any success.

The disk comes with a single label, unlike my LS-120 disk which came with two. This label does not wrap around the edge of the disk, instead only residing on its top surface. This might have been an improvement, since fold-over labels had a good habit of “releasing” from the disk over time.

For reference, the above images show both sides of the wrap-around insert card.

This now brings us to the interesting issue of the optical servo system. In the LS-120 article, there was some confusion since a clear radial pattern was seen in the marks. In the LS-240 disk, this same pattern is seen:

However, this time, with the aid of a proper macro lens, I was able to resolve it a little further:

So it seems like they are indeed concentric marks, of a 50/50 duty that go around. Mystery solved?

Zip250 Drive

Also as part of the haul was this Dell ZIP Module. Most of the time, I abhor laptop bay modules since they often use their own proprietary connectors, or at least need some disassembly and adaptation from standard connectors to be used on desktop machines.

As it turns out, this drive has exactly that – a Dell specific connector.

However, since it was a Zip250, I wasn’t going to give in so quickly since I only have one other Zip250 drive. It’s definitely valuable as a result. In a rather big coincidence, I found that it fitted my old Dell Latitude C600 laptop just perfectly …

… and I stuffed a ZIP 100 cartridge into it …

… and it functioned just fine right off the bat. That’s a great outcome. Unfortunately, as my only Zip250 cartridge is a pretty grotty one with bad sectors all over the media, I didn’t decide to test it in case it damaged the drive. But I’m definitely chuffed – I’ve got a second working Zip250 drive.


As it turns out, benchmarking different removable media drives gets quite difficult. Part of the reason is because how software handles drives and how Windows handles drives. The LS-120 drive, for example, comes up as a floppy disk drive making it unavailable to benchmarks such as HD Tune. The ZIP comes up as a regular Removable Disk, so it’s not as hard to benchmark. However, we need a common base if we are to come to the right conclusions about performance. There are also drive interface related differences.

Previously, I used the formatting time of the LS-120 as a guide to its performance. A reader pointed out that this underestimated the LS-120’s performance, which I came to accept.

To level the playing field, I decided to pitch an ATAPI ZIP100 drive against the ATAPI LS-120. A preliminary test with HDTune showed the ATAPI ZIP100 achieving a performance limit of about 1.2MB/s at the upper end, unlike the ZIP250 drive above which achieved 1.4MB/s but I suppose that’s “life”.

As HDTune is not a suitable bench, I decided to use ATTO instead. The file size was set to 64MB to fit on both types of media, and no overlapped I/O was used as the floppy disk did not have the benefit of write caching in Windows, so it would make it more “fair”.

The LS-120’s results were as follows:

The drive favoured read performance more than write performance. A read performance of about 400kB/s is achieved. The write performance reaches about 300kB/s at a transaction size of 128kB. Read performance reaches its peak by 16kB accesses.

The ATAPI ZIP was much more symmetrical in its performance, having read and write being almost equal. Nearly full performance was achieved by 32kB accesses, reaching about 1MB/s both ways. It’s clear that the ZIP was the superior performer, and the previous conclusion holds, at least for this set of conditions.

Of course, since the media does not operate at the same rate across the surface, it would be most useful to use a benchmark that fills the media. While not intended for this purpose, H2testW was “abused” to fill the media while timing it, and then verify its contents while timing it.

The LS-120 averages 331kB/s read and 246kB/s write across the whole surface with no errors.

The ZIP100 managed 998kB/s and 1024kB/s respectively, with no errors.

If using an LS-120 with a regular 1.44Mb formatted DS-HD floppy disk, it achieved about 16.8kB/s write and 48.3kB/s read. The slightly slow write performance may be due to the factory formatting which wasn’t done on the drive, but the read performance is faster than a regular floppy drive but not as fast as a “2x” drive.


It’s been a removable media bonanza all thanks to a very generous reader. All the drives survived the trip from Canberra to Sydney by coach, and it’s given me the impetus to do a benchmark that I’ve always wanted to do properly. Now that I have these drives, it gives me more drives to utilize when it comes to recovering submitted cartridges, be it ZIP100, ZIP250, LS-120, Syquest 44/88/200Mb or Hi-MD data.

But wait … there’s more! More to come in the next special post …

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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2 Responses to Canb2016: Special 1 – LS-120 & Zip250 Drives, LS-240 Disk & Benchmarks

  1. matson says:

    That LS-120 write HD floppy performance is depressing. Did you try a ‘dd bs=1440k oflag=direct’ full-shot? That might be faster than H2testw in Windows.

    Regarding laptop modular bay connectors: if you disassemble that module, then you will find that Iomega’s connector is proprietary! Regardless of PC brand, slimline ZIP drives have a unique connector (same for both ZIP250 and ZIP100). So one can “upgrade” a ZIP100 module to ZIP250, but one cannot find an “off the shelf, pre-made” adapter interposer board to connect those drives to enclosures or other hosts.

    You are always interesting. Happy Grav-Mass, Gough.

    • lui_gough says:

      Hi Matson!

      Merry Grav-Mass (or Happy Holidays … or whatever is the “accepted” term over there) to you too, and a happy new year.

      I was only testing for functionality of the LS-120 drive originally, so I didn’t think to boot a live USB and try direct dd-ing to the drive. It could well be possible that the factory format alignment wasn’t quite 100% to the LS-120’s liking, or maybe this drive is a little finnicky after having survived a bumpy 280km bus ride. I have no idea of its usage history, it could well be worn as well, but at least it completed the write-verify cycle okay, so it can’t be too bad. I might give that a go if I have some time to shove the drive into a machine with native IDE ports, but things are pretty hectic around this time. I’ll try to put up some other more (potentially) interesting stuff soon too :).

      – Gough

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