humtech@ucscc.UCSC.EDU (23050000) (01/25/89)
I've seen talk recently about formatting MFM drives using RLL neither of which I've ever heard of. I take it that they are some sort of hard disk formatting techniques or types of hard disks. Recently, I've decided that it's just too difficult to operate my 1040 via floppies - I can play games, but I can hardly run a shell and a compiler with tools. I have never owned a hard disk before. Does it make any difference which kind of hard disk I buy? Can I get a controller and cables for anything I get? I take it that I also need a controller, some sort of power supply (which I guess I can figure out from the specs on the drive mechanism), and some cables. I thought I heard something about an adaptor? Do most controllers support the MFM and RLL types? I'll probably buy a drive mechanism first so I guess I should make sure I buy the right one first. Price is definitely a consideration - I'm on a college student budget! Any help is greatly appreciated. Thanx Mark Frost Office of the the Computing Coordinator Humanities Division University of California at Santa Cruz Internet: humtech@ucschu.UCSC.EDU Bitnet: humtech@ucschu.bitnet
hase@netmbx.UUCP (Hartmut Semken) (02/01/89)
In article <6102@saturn.ucsc.edu> humtech@ucschu.ucsc.edu (Mark Frost) writes: > >I've seen talk recently about formatting MFM drives using RLL neither of which >I've ever heard of. I take it that they are some sort of hard disk formatting >techniques or types of hard disks. MFM and RLL (modified frequency modulation and run lenght limited) are methods to encode data (bytes) to be stored on media. They define a timing of the serial signal send to the hard disk (or received ...). The information is packed a little denser using RLL. Some (older) MFM drives cannot take the higher density. To put more information in the same place, RLL encoding uses less space for "clock" and similiar signals. That - and the increased density - squeeze some more capacity out of the same drive; 50% with RLL, 90% with ARLL (advanced RLL). Some people say, formatting an non-RLL drive with an RLL controller, voids the warranty. This is true for some drives: their media could take the higher density, but their electronic must no be used with signals, seldom returning to low level (line drivers blow up...). Most new drives can be used with RLL. If formatting with RLL does not work (media not capable ...), the drive isn't hurt and will run with any MFM controller. I prefer ARLL over MFM: it gives me twice the capacity and 2.5 times the speed... hase -- Hartmut Semken, Lupsteiner Weg 67, 1000 Berlin 37 hase@netmbx.UUCP If there is something more important than my Ego, I want it caught and shot. Now! (Zaphod Beeblebrox)
rosenkra@hall.cray.com (Bill Rosenkranz) (02/04/89)
--- there is an article in the most recent BYTE (feb?) on HD drivers. i have not read it yet but it looks promising... -bill