[comp.unix.ultrix] 766mb WrenVI really more like 647mb!!

hurf@batcomputer.tn.cornell.edu (Hurf Sheldon) (02/17/90)

Newsgroups: comp.unix.ultrix
Subject: Formatting Foriegn Drive on DS3100/UWS2.1
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Organization: Cornell Theory Center, Cornell University, Ithaca NY
Keywords: disk space, formatting, block size, disktab

	I just added a WrenVI drive to my system - the manual says
	it is 701mb formatted, 766mb unformatted. When I did a
	chpt -a /dev/rrz0a it picked up the number 1295849 as the top
	of the 'C' partition altough my calculations suggest it should
	be 1319490. I was unable to get a successful newfs on the
	drive using a top geater than 1295849 - this resulted in
	about 647mb formatted less 10% minfree leaves 580mb usable
	on a "766mb" disk. Blecch! It seems that the drive can be formatted
	in different block sizes but using newfs -S 1024 had no
	effect on the formatted mb figure.

	Any illumination would be gratly appreciated.





-- 
     Hurf Sheldon			 Network: hurf@ionvax.tn.cornell.edu
     Lab of Plasma Studies		  Bitnet: hurf@CRNLION
     369 Upson Hall, Cornell University, Ithaca, N.Y. 14853  ph:607 255 7267
     "And the walls came tumbling down"

hurf@batcomputer.tn.cornell.edu (Hurf Sheldon) (02/17/90)

	In a followup to the previous posting i find that
	the '1295850' is 53x15x1630 which works out to
	53 sectors/track x15 tracks/cyl x1630 cyls
	
	So it seems 1 sector is held in reserve and 2 cylinders
	I don't know if this is the result of the system formatting
	defaults or the factory formatting. Anyhow - a '760meg disk'
	is really 600meg of usable system space.
-- 
     Hurf Sheldon			 Network: hurf@ionvax.tn.cornell.edu
     Lab of Plasma Studies		  Bitnet: hurf@CRNLION
     369 Upson Hall, Cornell University, Ithaca, N.Y. 14853  ph:607 255 7267
     "And the walls came tumbling down"