Wtd: ESDI 3.5" hd + hd ?'s - test-drb@ccmp.vtda.org

6 Jan 1998

...
   MFM (early
80's?)  
 Very early 80's, I think, for the ST-506.

  RLL (late 80's?)  
 I tend to think of this as a minor variation of MFM, myself :-) 
Not quite. The interface is the same (ST-506/412), but the encoding is
different.

RLL-encoded ST-506/412 drives were finicky, especially as regards
temperature -- you shouldn't LLF them cold, for example.

Actually, some (if not all) IDE's use variations of RLL encoding.