Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!asuvax!ncar!elroy.jpl.nasa.gov!usc!pollux.usc.edu!kjh From: kjh@pollux.usc.edu (Kenneth J. Hendrickson) Newsgroups: comp.os.minix Subject: Re: PC Minix demo (questions) Keywords: demo, 360k/1.2MB drives, 720k/1.44MB, help! Message-ID: <30843@usc> Date: 7 Mar 91 20:02:48 GMT References: <1991Mar5.055145.7352@csus.edu> <1991Mar5.214921.1010@unixg.ubc.ca> <9229@star.cs.vu.nl> Sender: news@usc Organization: EE-Systems, USC, Los Angeles Lines: 31 Nntp-Posting-Host: pollux.usc.edu In article <9229@star.cs.vu.nl> ast@cs.vu.nl (Andy Tanenbaum) writes: > 1. Format a 360K DD diskette on a 360K drive (i.e., a friend's machine). > In theory, formating a DD diskette as 360K on a 1.2M drive is not really > supposed to work due to the different drive head width. There are only two problems that could occur using a 360k disk in a 1.2M drive: 1 Software could try to read from a track larger than 39. 360k disks only have 40 tracks of 9 sectors/track. 2 If you write to a 360k disk on a 360k drive, and then write to the disk on a 1.2M drive, you may have problems using the disk again on a 360k drive. This is because of the wide/narrow head problem. There will never be a problem using a 360k disk on a 1.2M drive due to head width, regardless of where the disk was previously used. Problem 2 can and will occur independent of operating system. Problem 1 will never occur in DOS. It does occur in the current bootblok for Minix. I suggest that a config program be put in the tools directory, so that the correct bootblok can be used for the boot disk being made. Disks are only of one type (a 360k disk will never become a 720k disk :-) and one knows what type of disk he is using when he makes a boot disk. I have posted my cdiffs for this before, and I will do so again upon request, if they haven't gotten into somebodies archives. -- favourite oxymorons: student athlete, military justice, mercy killing Ken Hendrickson N8DGN/6 kjh@usc.edu ...!uunet!usc!pollux!kjh