*BSD News Article 6197


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From: veit@du9ds3.uni-duisburg.de (Holger Veit)
Newsgroups: comp.unix.bsd
Subject: Re: How to format UNIX floppies under 386BSD
Date: 7 Oct 92 08:10:51 GMT
Organization: Uni-Duisburg FB9 Datenverarbeitung
Lines: 36
Message-ID: <veit.718445451@du9ds3>
References: <1992Oct5.153315.22272@ninja.zso.dec.com> <1992Oct6.145844.669@rucs2.sunlab.cs.runet.edu> <1992Oct6.173648.13606@ninja.zso.dec.com> <1asvcfINN7qu@network.ucsd.edu> <1992Oct7.022247.26696@ninja.zso.dec.com>
Reply-To: veit@du9ds3.uni-duisburg.de
NNTP-Posting-Host: du9ds3.uni-duisburg.de

In <1992Oct7.022247.26696@ninja.zso.dec.com> alan@ulka.zso.dec.com (F. Alan Jones) writes:


>brian@ucsd.edu (Brian Kantor) writes:

>|> The manual for the floppy controller chip shows you precisely what
>|> you need to do to format a floppy.  If you want to see example code that
>|> implements that flowchart, look at the IBM PC Technical Reference
>|> Manual in the BIOS listing, or at any of the older CP/M BIOSs.

>Thanks for the reply Brian.  So, what make/model is the floppy controller
>chip on a stock PC?  When I have that, I can write the manufacturer.  My

NEC uPD 765 (often, however, hidden in an ASIC, so you might not see this 
type id on the FDC chip). The IBM hardware (in particular the encoding of
drives) is not exactly what is proposed in the data sheet. Best you'd take
a look into the BIOS listing in a IBM AT Tech.Ref. Manual. If you want to
implement low level formatting, only define an ioctl function for that in
the fd driver. The exact disk layout (e.g. gaps, sector filling, etc. should 
remain the job of some format utility. Take the DOS INT 10h format subfunction
as a hint.

>PC is a "street" machine with no docs.  I assume the IBM PC Tech Ref is
>off the shelf and still in print.

>Alan
>P.S.  I get the idea.  Looks like driver code with raised IPL.  Did we say
>this was a real time OS (just kidding)?

Holger

-- 
|  |   / Dr. Holger Veit         | INTERNET: veit@du9ds3.uni-duisburg.de
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