Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!rutgers!okstate!uokmax!rmtodd
From: rmtodd@uokmax.UUCP (Richard Michael Todd)
Newsgroups: comp.os.minix
Subject: Re: Up on Compaq portable (with fixes & tools)
Message-ID: <561@uokmax.UUCP>
Date: Fri, 1-May-87 22:39:48 EDT
Article-I.D.: uokmax.561
Posted: Fri May  1 22:39:48 1987
Date-Received: Sun, 3-May-87 04:06:16 EDT
References: <1416@drivax.UUCP> <450@yabbie.oz>
Organization: University of Oklahoma, Norman, OK
Lines: 41
Keywords: disk DOS tools utilities
Summary: To use cp or dd, you gotta have someplace to put the file...

In article <450@yabbie.oz>, rcodi@yabbie.oz (Ian Donaldson) writes:
> A question: why do you need a special program to do this?
> Surely the "cp" or "dd" commands can do this by something like:
> 	cp /dev/rflp file
>     or:
> 	dd if=/dev/rflp of=file
>     "rflp" might be the name of the RAW floppy device (I don't know
>     exactly what its called on MINIX since I don't have the source yet
It's /dev/fd0 (drive 0,  drive 1 is /dev/fd1)
> If MINIX is reasonably V7 compatable, both these commands should
> be equivalent to the FREAD program supplied.  Similarly for FWRITE.
> And they -don't- depend on any hardware or interrupt vectors like the 
> given programs.
The cp and dd commands will work on MINIX just fine -- IF you have someplace
to write the output file.  If you're like me, with only one floppy drive
and a hard-disk that MINIX won't write to, there's no place to put a
360K image of the disk.  In that case you have to do your copies under
Mushdos, using either a program like COPYIIPC or a poor man's substitute
like the fread or fwrite commands.
If you have two floppy drives, you can just use
	cp /dev/fd0 /dev/fd1
to do the copies.

> If you want it to go faster you can put a "bs=64k" on the "dd" command,
> if 64k dma is possible (or simulated).  You should be able to achieve
> the same sort of speed that the given programs would have achieved this way.
Even if you put a "bs=64k" parameter on the dd command, the floppy task
will still read the disk in two-sector (1K) chunks.  
> If the kernel doesn't support the raw floppy device, then 
> code should be added to the kernel.  I just dislike programs that
> go straight to the hardware if there is a portable way to do it
> and utilities already exist.
So do I, but there are some conditions where you can't use the supplied
utilities, for the reasons described above.  Incidentally, the FREAD and
FWRITE programs the poster is referring to seem to do their I/O with BIOS
calls, which isn't quite at the hardware level.  (If your floppy disk
harrdware isn't "truly compatible" you won't be running MINIX anyway).
--------------------------------------------------------------------------
Richard Todd
USSnail:820 Annie Court,Norman OK 73069
UUCP: {allegra!cbosgd|ihnp4}!okstate!uokmax!rmtodd