Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cwjcc!tut.cis.ohio-state.edu!osu-cis!att!occrsh!rjd
From: rjd@occrsh.ATT.COM (Randy_Davis)
Newsgroups: u3b.tech,comp.sys.att
Subject: Re: 3B2 Floppy Drive
Summary: Exact usable size of floppy disk
Message-ID: <545@occrsh.ATT.COM>
Date: 30 Jan 89 21:24:37 GMT
References: <581@mccc.UUCP> <1037@vsi.COM>
Reply-To: rjd@occrsh.UUCP (Randy_Davis)
Followup-To: u3b.tech
Organization: AT&T Network & Data Systems, OKC
Lines: 23

In article <1037@vsi.COM> friedl@vsi.COM (Stephen J. Friedl) writes:
|In article <581@mccc.UUCP>, pjh@mccc.UUCP (Pete Holsberg) writes:
|> 
|> Is /dev/rdiskette on a 3B2/400 a 720K device, a 1.4M device, or a 1.2M device?
|
|
|Let's work it out:
|
|	80 tracks   9 blocks   2 tracks   512 bytes   737280 bytes
|	--------- * -------- * -------- * --------- = ------------
|	 drive       track     cylinder     block         drive
|
|
|So, it's 720k (but you only get to use 79 tracks...)
|
|     Steve

 Well, to be exact, its 728,064 bytes, easily verified by doing a dd from
either raw or block floppy device (with a formatted disk in the drive and the
door closed) into a file.

Randy Davis					UUCP: ...(att!)ocrjd!randy
						      ...(att!)occrsh!rjd