Odds and Ends (Questions on 3B1)

[Gary S. Trujillo]

In article <1078 at naucse.UUCP> sbw at naucse.UUCP (Steve Wampler) writes:
>I have a few questions that have been puzzling me.  Nothing
>earth shattering, but I'm curious...
>
>(2) Has anyone tried to rewrite the ms-dos formatter to format
>    at 9 sectors instead of 8?...

Well, it's been several months, and some folks may have missed the answer
from Roger Abrahams that I received in response to my having asked that
same question, so I'll quote him again on the subject:

|From tailorme!marque.uucp!roger
|To: gst at gnosys.uucp
|Subject: Re: Minor fix to Mtools patch for 3.5" disks
|Newsgroups: unix-pc.bugs,comp.sys.att,unix-pc.general
|In-Reply-To: <56 at gnosys.UUCP>
|References: <611 at bacchus.UUCP>
|Organization: Marquette University, Milwaukee, WI
|Message-Id: <8808212331.AA09610 at marque.mu.edu>
|Date: 21 Aug 88 23:31:02 CDT (Sun)
|From: Roger Abrahams <roger at marque.mu.edu>
|
|In article <56 at gnosys.UUCP> you (I) write:
|>In article <611 at bacchus.UUCP> darren at bacchus.UUCP (Darren Friedlein) writes:
|>>...
|>>One thing I'd like to find is a program like MsdosF.sh that will format
|>>3.5" disks.  Anyone know how to do this?
|>
|>For that matter, does anyone know how to format 5.25" floppies at 360K?
|>Far as I know, /usr/bin/MsdosF.sh will only format 320K (8-sector) disks.
|
|Wrongo!  If you have "strings", you can see that the program that does the
|actual format (md_format) has the following options: -1289bv
|
|If you say "md-format -9" you will get a 360k disk.  Actually unix can't make
|a 9 sector disk (odd sectors are reserved for bad block mapping on a hard
|disk, and this is also how it tells a hard from a floppy disk), so it
|actually makes up a 10 sector format, but only allocates 9 sectors.
|
|I leave the rest of the options to you, to figure out yourself...
|
|						- Roger

I hope this answer helps you as much as it did me.  The only problem is that
I have found that I sometimes have problems reading floppies thus formatted
when I try to read them on a MS-DOS machine.  It may have to do with the El
Cheapo diskettes I tend to use, or an alignment mismatch, or other factors,
but the additional density necessary to write 10 sectors may also have some-
thing to do with the problem.  Far as I know, the UNIXpc cannot format disks
with an odd number of sectors, though it can read them OK.  Roger explained
the situation to me, but I've forgotten the details.

-- 
Gary S. Trujillo			      {linus,bbn,m2c}!spdcc!gnosys!gst
Somerville, Massachusetts		     {icus,ima,stech,wjh12}!gnosys!gst