Tony wrote: If it's not already on the web somewhere, please send it to me, and I'll add it to my retrocomputing pages. I didn't get a C8 with my 6085, so I could certainly use this info. I've been thinking about designing an interface card to replace ST-506 interface drives with ATA (IDE) drives. It's getting hard to find Maxtor 2190s at a decent price, and I'm not sure how many more years it will be possible to keep them running at all. The basic concept would be to simply sample the MFM (or RLL) channel code at somewhere around 50 MHz as it is being written, and store the data on the ATA drive. The interface would keep one track buffered in RAM. Whenever the host requests a head change or seek, the buffer would be written to the ATA drive (if it is dirty), and reloaded with the data for the new track. This would require a much larger ATA drive than the original drive it is emulating, 102K bytes per track. To emulate a Maxtor 2190, this requires a 2G ATA drive. You could even emulate drives larger than that by emulating more cylinders. The tricky part is that it might be necessary for the simulated drive to mimic the effect that write precompensation in the host's controller is intended to circumvent.

"Seth J. Morabito" <sethm(a)loomcom.com> wrote: The technical impediment is that the bridge would have to actually decode the channel code back into logical data (on writes from the host), and vice versa. This is technically feasible and could be implemented in a small FPGA. However, there isn't actually a standard for it. Not all MFM controllers on PCs even use the same format, and generally they are different from the DEC RQDX2, which is different from the RQDX3, etc. Assuming that that problem is solved, the next problem is that an XT2190 (RD54) stores more data than will fit on a ZIP disk. When's Iomgega going to introduce a 200M ZIP? Sony's HiFD is supposed to have 200M capacity, but it isn't shipping yet. But a 100M ZIP disk would make a perfectly fine RP06 replacement. Just in case anyone here is thinking about using modern removable-rigid-media drives, my advice is: DON'T. Neither Syquest nor Iomega has any clue how to make high-density removable rigid media work. Assuming that it is even possible, and I'm not convinced it is. I bought an Iomega Jaz drive soon after it was introduced. It worked well enough for a few weeks that I bought four more for my other computers. But sectors keep going bad, and one of the drives failed, physically damaging the media. The other drives were able to reformat their media, but more sectors just go bad eventually. Syquest Syjet and Sparq drives are even worse. We tried to use them at work, and they only last a few weeks before breaking. We've had to send them in for replacement so many times that it is no wonder that Syquest has gone bankrupt. On the other hand, I've had nothing but good luck with ZIP drives (which use floppy media). I think the problems with removable rigid media stem drive and disk cartridge; they've tried to use Winchester drive technology without understanding its inherent limitations. Eric

[Continuing a discussion about modern removable-media disk drives, which would be off-topic except that we want to use modern drives on old computers.] You may as well forget about using any modern magnetic disk drives, then. Service manuals don't exist (or are useless). Descriptions of the low-level format are only available if the format has been blessed by a standards committee such as ECMA. I'd love to see an ECMA standard for ZIP disks, but I doubt that it will happen. On the other hand, ECMA has published standards for various optical media, including CD-ROM, PD, DVD-ROM, DVD-RAM, and +RW. Air filters? Ha! They have nothing but a shutter on the cartridge and a door flap on the drive. Absolute rubbish. It's miraculous that they work even for a few weeks.

On 12 Nov 1998, Eric Smith wrote: I've had no problems with the SyQuest 135MB EZ-Drive and the 200MB EZ Flyer. I've used the EZ-Drive more. SyQuest is dead though. They went belly up just last week. Start collecting those SyQuest drives! I took my EZ Drive out of its external case and installed it into a 3.5" bay on my PC. Since its SCSI, it plugged right into my SCSI chain and is a perfect backup device. This particular drive has been running fine for over 2 years now. SyQuest was always known for their poor quality though. You seem to have way worse luck than me with your SyQuest drives. Now that you've exposed its flaws, mine will probably crash tomorrow. Thanks alot! Sellam Alternate e-mail: dastar(a)siconic.com ------------------------------------------------------------------------------ Always being hassled by the man. Coming in 1999: Vintage Computer Festival 3.0 See http://www.vintage.org/vcf for details! [Last web site update: 11/02/98]

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