Path: utzoo!attcan!uunet!lll-winken!lll-lcc!rzh
From: rzh@lll-lcc.UUCP (Roger Hanscom)
Newsgroups: comp.sys.ibm.pc
Subject: Hard Drive Characteristics
Keywords: heads, cylinders, FAT
Message-ID: <2369@lll-lcc.UUCP>
Date: 18 Mar 89 20:50:34 GMT
Organization: Lawrence Livermore Labs, LCC, Livermore Ca
Lines: 23


Does anybody know where a hard drive's parameters are known (or
determined) ??  You do a low-level format of the drive by entering
firmware on the controller card....does the controller have some
sort of an internal table that gives these parameters.  When you
run FORMAT, how does it know (for example) how many heads are in
the hard drive??  Is any of this controlled by the BIOS??  Why does
DOS refuse to deal with FORMAT C:/N:xx , where xx is less than the
drive's xx-max??  Is the set of hard drives a controller will work
with closed??  (By that I mean will a controller that was built
when there were no 13-head drives with 2000 cylinders be able to
handle a drive with these characteristics??  Or is the limitation
more a function of raw number of sectors on the entire device??)
One frequently encounters comments about the "32 MByte" limit --
what dictates this "limit" (is it as I suspect, the size and # of
bits per entry in the FAT) ??

Enough questions for today!  Thanks for your attention.

===================================================================

Roger         rzh@lll-lcc.llnl.gov
              {ucbvax,ames,....}!lll-lcc!rzh