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.
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 …
… 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!
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.
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.
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.
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!
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.
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 …
… 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.
As this drive was manufactured to go into an external enclosure, it has no front bezel. This is rather unfortunate, but not fatal.
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.
The drive itself was manufactured November 1997 as can be seen in the serial barcode label attached to the side of the drive.
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, 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.
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 ATAPI
ZIP 100 Pocket USB
ZIP 100 SCSI
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.