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Hardwaretest: Diskettenlaufwerk LS-120 (von Gary Colville)

»It's a sad fact that while high density floppy drives have long been standard on PCs and Macs almost all Amiga owners still strugle on with old double density drives. At some time or other, most Amigans will have looked at ads for Amiga-adapted high density drives, thought about buying one, then looked at the price and quickly dismissed the idea. Emulation enthusiasts, who really need HD capability, are about the only people who buy them.

Recently, removable-storage drives like the Iomega Zip have become popular. They won't read high density floppies but they will let you swap data with the many PC and Mac users who own one, and they make great backup devices too. The Zip, however, isn't without it's own problems. Zip disks are fairly expensive and the IDE version of the drive has gained a reputation for working erraticaly on the Amiga.

Wouldn't it be great if there was a Zip-like removable drive that could read HD floppy disks and worked okay with the Amiga's IDE port?

Well, now there is. The new LS-120 is an enhanced high density 3.5" floppy drive that uses the ATAPI bus system and is capable of storing 120Mb on a special disk or 1.44Mb on standard HD floppy disks. Amiga drivers for the LS-120 come included with IdeFix '97, which you can find on Aminet.

It was the presence of these drivers that originaly got me thinking about the LS-120. The few hands-on reviews of the drive that I could find seemed mostly favourable so, cash in hand, I plodded off the the local Wintel hardware emporium. Ten minutes and 89ukp later I emerged clutching an OEM type LS-120 (the OEM package consists of the LS-120 and a Dos/Windows driver disk. No manuals or cables or the like).

The LS-120 is most often described as a 'Superfloppy' and you can see why when unpacking it for the first time. It looks exactly like any cheap floppy drive, right down to the layout of the PCB. The only visible difference is the 40-pin connector on the back and the little triangle-and-globe LS-120 logo on the dust flap.

Physical installation is quite easy; Just connect the IDE data cable and set the Master/Slave jumpers. A word of warning here: My LS-120 came with the jumpers set to CS (Cable Select) and this can cause real problems if it's not changed to MS (Master) or SL (Slave) before you try installing the IdeFix drivers.

IdeFix 97 contains specific LS-120 support, and it performs admirably. Running the "MountLS120" program produces a pair of new AmigaOS devices: DF4 for disks formatted using OFS/FFS and PC4 for MS-DOS disks. Also included are a couple of utils for low-level formatting 120Mb disks. Don't use these unless you really have to, as formatting can take upwards of 40 minutes to complete.

The DF4 device provided by IdeFix treats the LS-120 like a huge floppy disk (indeed, you can even access it via trackdisk.device as unit 4) but you don't have to do it this way. The LS-120 can take a RDB and be mounted via a normal DosDriver, just like any other IDE drive. If you want to use an alternate filesystem like AFS, this is your only option. RDPrep crashed every time I tried to use it to access the LS-120, but HDToolBox coped without problems.

So, what's it like in use? Popping a fresh 120Mb disk into the drive produced about 10 seconds of grinding before an icon appeared on workbench. LS-120 media comes formatted for MS-DOS. Re-formatting for FFS takes a while, but presents no problems unless the disk's write-protect tab is engaged. Unlike some other removable drives, write-protection on the LS-120 is physical. Once that tab is opened nothing can write to the disk.

Copying a block of files to the drive showed it to be fast, but not lightning quick. If feels much faster than my 4x CD-Rom even if the benchmarks I've done suggest otherwise. Running a mixture of benchmark programs on a blank 120Mb disk shows a transfer rate in the region of 350K/sec. The following figures were generated by DiskSpeed using a blank 120Mb disk and 200 FS buffers. The Amiga used was a 33MHz 68040 based A1200T.

Testing directory manipulation speed.
File Create: 143 files/sec | CPU Available: 52%
File Open: 458 files/sec | CPU Available: 0%
Directory Scan: 2181 files/sec | CPU Available: 0%
File Delete: 526 files/sec | CPU Available: 0%

Seek/Read: 14 seeks/sec | CPU Available: 96%

Testing with a 262144 byte,
MEMF_FAST, LONG-aligned buffer.
Create file: 351099 bytes/sec | CPU Available: 80%
Write to file: 360335 bytes/sec | CPU Available: 80%
Read from file:374669 bytes/sec | CPU Available: 79%

Average CPU Available: 48% | CPU Availability index: 1902

Some tests using various filesystems and block sizes show the LS-120 is very sensitive to changes in either. Performance using FFS with standard 512 byte blocks is nothing special, but increasing the block size and/or switching to another filesystem (AFS or MSDOS) improves things. Also, the LS-120 sometimes pauses for 5 or 6 secods to re-calibrate itsself, so throughput in non-benchmark operations will be a little lower than shown here.

One of the main reasons I bought the 120 was it's ability to read 1.44Mb floppies (but not, sadly, 880k or 1.76Mb Amiga-style disks). Popping a PC disk into the drive results in a few seconds of very nasty grinding sounds (you get used to these after a while) and the normal disk icon appearing on Workbench. The LS-120 has a very natty CD-style motorised eject, so now it's possible to eject floppy disks without having to grope around for the eject button. The front panel eject button has a small poke-a-pin-in hole to facilitate manual ejection of stuck disks.

Although the drive is limited to 720K and 1.44Mb disks, and not 880k or 1.76Mb, it's quite possible to format these using FFS or AFS rather than the MS-DOS filesystem. It should also possible to use the LS-120 with Mac and PC emulators but in practice this is a rather hit and miss affair. PCx and PC-Task refuse to see the LS-120. Shapeshifter uses it perfectly in both floppy and 120Mb modes. I can't comment on Fusion as I don't have access to it.

When accessing floppies the LS-120 shows significant speed advantages over the standard Amiga floppy:

These results are from the LS-120, accessing a 1.44Mb disk:
Seek/Read: 769 seeks/sec | CPU Available: 70%

Testing with a 262144 byte,
MEMF_FAST, LONG-aligned buffer.
Create file: 17961 bytes/sec | CPU Available: 98%
Write to file: 15489 bytes/sec | CPU Available: 98%
Read from file: 49164 bytes/sec | CPU Available: 96%

and these are from the standard internal 880k floppy:

Seek/Read: 4 seeks/sec | CPU Available: 97%

Testing with a 262144 byte,
MEMF_FAST, LONG-aligned buffer.
Create file: 11200 bytes/sec | CPU Available: 96%
Write to file: 10813 bytes/sec | CPU Available: 96%
Read from file: 22767 bytes/sec | CPU Available: 97%

Nothing about the LS-120 stands out as being amazingly wonderful, but lots of little things combine to make it a great drive. It's use of the cheap and common IDE interface, large 120Mb disks, and ability to read 1.44Mb floppies all add up to a very nice package. The biggest point in favour of the LS-120 has to be it's price. Amiga HD floppy drives sell for about 60ukp here, so a combined HD floppy and 120 meg removable drive for less than 90ukp is almost too good to be true.

For some applications the LS-120 is a little slow, and I hope the designers can reduce the 10 seconds needed to mount a 120Mb disk to something a little shorter. It's quite noisey, too. The grinding and clunking can be very noticible, particularly when mounting 1.44Mb and 720K disks. This isn't a problem for me as the PSU in my tower case drowns most of the noise, but if you have a standard 1200 with a quiet hard disk it could prove distracting.

After almost two months use my main feeling about the LS-120 is that it's a superb drive sold at a crazily low price. If you have any need for a removable storage drive, put the LS-120 right at the top of your list. If just need an HD floppy, give serious consideration to spending a little extra and getting an LS-120.