>From an article I wrote a while back: ----------------------------------------
As there are so many USB 1.x-compatible products currently coming out that it's hard to keep track, I will mention just a few: 1) While there were complaints about the original version, the final version of the Imation (http://www.imation.com/) SuperDisk USB 2x External Floppy Drive (http://www.superdisk.com/) currently appears to be the most popular of the external USB Floppy Drives; The SuperDisk drive supports Mac OS 1.4 Floppy Disks, RLL encoding for only the SuperDisk media, and MFM encoding for 1.44 and 720 (IBM format) media. It can also read 1.68 MB DMF or "Distribution Media Format" floppy disks (Microsoft uses DMF 2048 for the floppy versions of some of their softwares), and both 1.2 MB (3 1/2 inch) Japanese formats. Imation has stated that they have worked on resolving some of the previous issues complained about, including the problems with Multi-Floppy installs. Imation may discontinue the SuperDisk Drive; See: http://www.maccentral.com/news/0011/28.imation.shtml. There are two SuperDisk limitations that prospective buyers should be aware of: a) Since the entire Computer Industry (all Platforms) has not been willing to establish a Standard, currently not all types of Personal Computer on any Platform can boot off of any external USB Peripheral (except on the newer machines from APPLE); b) Since the The SuperDisk drive does not have a Floppy Disk Controller built into the drive (Imation says that it uses an IDE/ATAPI drive with a USB interface adapter connected to it), it cannot read the old Mac OS 400 and 800 KB Floppy Format. Imation states that the old Mac OS 400 and 800 KB Floppy Disks use what is called GCR data encoding (Group Code Recording; a particular code of the RLL or "Run Length Limited" data encoding method often used on data cartridge drives. The code combines high data density with relative ease of decoding). So, GCR encodes the data so 4 bits of data become 5 bits on the disk. Imation also stated that this was: "Less efficient than MFM (aka "Modified Frequency Modulation") data encoding, but GCR had much more decode margin..." (Some experts would disagree that MFM is more efficient than GCR). In addition, the old Mac OS 400 and 800 KB Floppy Format is recorded on the disk in four zones, and these zones sometimes required the disk to be spun at different speeds to compensate for frequency differences. The old APPLE internal "SuperDrive" Floppy Disk Drives had a modified Floppy Disk Controller that varied the motor speed to stuff more data onto the disks. ADVICE: Keep your older machines; If your model(s) support it, run Mac OS 7.1 with Update 3, for mounting 400 KB Mac Floppy Disks. Run Mac OS 7.5.5, or 7.6.1 on them, if you have problems mounting older 800 KB Floppy Disks under Mac OS 8, 9, or X. With the older machiness' APPLE "SuperDrive" Floppy Disk Drives around, you can also tranfer files via Ethernet, or on to an Iomega Zip Disk, etc., if you own lots of older programs that have to be installed off 400 and 800 KB Floppy Disks (besides, if they are Power Macintoshes, most of them can be good Servers using MkLinux or LinuxPPC, if you desire). While I understand the desire to eventually cease using Floppy Drives, is a pity that APPLE didn't choose to make the APPLE "SuperDrive" Floppy Disk Drives available as an customer option in the form of external USB and SCSI models, so that the phase-out of Floppy Drives was a gradual thing, rather than a sudden jolt. ---------------------------------------- -- Compact Macs is sponsored by <http://lowendmac.com/>. Support Low End Mac <http://lowendmac.com/lists/support.html> Compact Macs list info: <http://lowendmac.com/lists/compact.shtml> The FAQ: <http://macfaq.org/> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/compact.macs%40mail.maclaunch.com/> --------------------------------------------------------------- >The Think Different Store http://www.ThinkDifferentStore.com ---------------------------------------------------------------
