Path: utzoo!utgpu!attcan!uunet!lll-winken!ames!haven!uflorida!gatech!prism!stan
From: stan@hydra.gatech.EDU (Stan Corbin)
Newsgroups: comp.sys.sequent
Subject: Re: Fujitsu M2372 formatting info (for ZDC)?
Message-ID: <170@hydra.gatech.EDU>
Date: 7 Jan 89 03:50:34 GMT
References: <8614@pasteur.Berkeley.EDU>
Reply-To: stan@prism.gatech.EDU (Stan Corbin)
Distribution: na
Organization: Georgia Institute of Technology, Atlanta
Lines: 25

In article <8614@pasteur.Berkeley.EDU> aoki@postgres.Berkeley.EDU (Paul M. Aoki) writes:
>As far as the /etc/disktab entry goes, I can figure out everything
>except "ns".  Following the wonderful instructions in the Fujitsu
>manual I get ns#80.  That's fine with me, but the Swallow 5 entry is
>ns#81, and
>
>	ns * nt * nc+3 * 512 = 81 * 27 * 748 * 512 = 838MB
>
>which is not the size of a Swallow 5.  So the Sequent folks did
>something funny -- they aren't using all of the disk.

I believe that zdformat uses one "spare" sector at the end of each track
for remapping bad sectors.  Therefore, the number for ns in /etc/disktab
should be one less than the actual number of sectors per track that the
drive has.  In other words, when computing the capacity of the drive, you
should use ns+1 (just like you used nc+3).  Also, if you are trying to
compute the total unformated capacity, you should used the actual sector
size including headers (I think usually around 600 - 650) rather than
512.

-- 
Stan Corbin					       stan@prism.gatech.edu
Office of Computing Services			       ...!gatech!prism!stan
Georgia Institute of Technology 
Atlanta, Georgia  30332-0275