larry@nstar.UUCP (Larry Snyder) (03/14/90)
In article <614@sixhub.UUCP>, davidsen@sixhub.UUCP (Wm E. Davidsen Jr) writes: > > Trust me, that's not how it works. Any form of RLL does not "make the > drive spin faster" not does it "put the bits closer together." It gets > compression by putting the bits farther apart and measuring the distance > between them more closely. > > A drive which is marginal MFM may be unusable RLL when it gets a > little hotter than normal, but NOT because it's spinning faster. The > drive spins even with no controller at all. A couple of months ago I added another controller (1542) and a large SCSI drive to my existing controller/drive combination - and like most of the midwest - we have been experiencing a "heat wave". Along with this heat (in the 90's in the computer room) read errors started appearing on the SCSI drive - and after removing the cover off the box the SCSI drive is too hot to touch. With the 50 conductor ribbon cable it's hard to keep from blocking the air flow into the power supply for the fan to shove out - but I tried :). I also replaced the fan in the PS with one that moves more air - and likewise placed a fan in the front of the machine which is sucking air in and blowing in over the boards in the expansion slots. Reference the perstor boards - I have heard many stories of them actually destroying drives by pushing the electronics beyond specs. Miniscribe, Seagate, CDC - none of the vendors certify their products for use with the Perstor cards - and as a matter of fact, the Perstor products actually decrease the transfer rate (matched against a 1:1 MFM or RLL controller) with data throughput running around 300 kb/sec. If you value your data and hardware - run them with approved controllers. - -- The Northern Star Public Access Unix Site, Notre Dame, Indiana USA uucp: iuvax!ndmath!nstar!larry internet: larry@nstar USR HST 219-287-9020 * PEP 219-289-3745 * Hayes V9600 219-289-0286