🚀 go-pugleaf

In article <exuptr.457.716058876@exu.ericsson.se> exuptr@exu.ericsson.se (exuptr@exu.ericsson.se) writes:
}In article <Bu34nA.3FB.2@cs.cmu.edu> ralf+@cs.cmu.edu (Ralf Brown) writes:
}>The more immediate limit to IDE (and ESDI) is likely to be the size of the
}>drive.  If (as I suspect), the WD-1003 only permits 16 heads, then the
}>limit on IDE is 504 MB (1024 cylinders * 16 heads * 63 sectors/track); even
}>if a full 64 heads are available, the limit is less than 2GB--a size which
}>is already readily available even if not yet cheap ($3000+) in SCSI
}>versions.
}
}What's the WD-1003 got to do with it?  I'm using an IDE right now with 32 
}heads defined, and 48 spt.

The IDE interface emulates a WD-1003 controller, which is the original
controller for which the IBM AT's ROM BIOS was written (the PC and XT
ROM BIOSes don't contain code for hard disks).  Since I don't know the
register-level interface to the WD-1003, I was erring on the side of
caution--the head number could easily have been a bitfield in a
register, with the other four bits being used for other things.
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