Newsgroups: comp.os.msdos.apps

Note: This is my response to Massimo Cotrozzi's latest response with the
      subject ">Floppy viewer/editor for non MS/DOS formatted disks".
      Note the leading ">". If everything goes well then this (my)
      response will be "attached" to the old string, i.e. without the
      leading ">" in the subject.
      In the text of Massimo's response there is one too many leading
      "> " on most lines.
      Sorry for this nitpicking, but this problem is already hard
      enough, I think we can do well without communication problems.

cotrozzi@ghost.dsi.unimi.it (Massimo Cotrozzi) writes:
> > cotrozzi@ghost.dsi.unimi.it (Massimo Cotrozzi) writes:
> > 
> > > The bad news continue ..
> > > DiskEdit allows me to die while trying to read that damned diskette
> > 
> >   What does "allows me to die" mean? I.e. what happens? Details please.
> > 
> It means that I tried the instructions you gave me with nu 4.5 in /M mode
> and it took almost 25 minutes to produce a 0K output file ( meanwhile
> the drive was making terrible noises )

  I see. I think, as soon as you have a new 5.25" disk drive, you first
have to determine the physical specifications of the Star Dos diskettes.
So, for now, do not use my instructions to try to copy the *whole*
diskette with nu 4.5 in /M mode. See below.

> > > BUT CopyQM AND Teledisk ( Sydex ? ) allow me to copy the diskette
> > > to the HD in two ways ( wrong ways for what concerns my problem.)
> > > 
> > > CopyQM tells me :	256 Sectors ( I suppose it is the sector size )
> > > 			15 sectors/track
> > > 			2 side
> > > 			low density
> I succeeded in reading the disk with copyqm in blind mode and making a copy 
> of it in a file but I wonder if it is an exact copy of the disk ...

  This info is very strange. The "256 Sectors" does not make sense (i.e.
too much for a track/cylinder, too little for the whole disk) and "15
sectors/track" are, as far as I know, only used for High Density (1.2MB
on MS-DOS) diskettes.

> >   Do you know the physical specifications of the Star Dos disks you are
> > trying to copy? I.e. size (5.25" or 3.5"), density (single, double,
> > high), number of sides used, number of tracks, number of sectors per
> > track, number of bytes per sector.
> >   If you do not know all of these then please give us the ones which
> > you do know.
> OK : 	size 5.25" 
> 	single density ( supposed ) 
> 	2 sides used 
> 	15 sectors per track ( from copyqm's output )
> 	256 bytes per sector ( from copyqm's output )
> 	number of tracks : I suppose 40 but I will not be 
> 			   surprised if it turns out they are 80

  As I said, I would not rely on copyqm's output. Don't you have any
information from the system on which the diskettes were formatted/
written? What does it say, if anything, in the human-readable writing on
the outside of the diskette and its enveloppe about capacity (i.e.
bytes) and density? Please give as much detail as possible.
	
> >   Also NU in /M mode has an information screen which tells you what NU
> > thinks the physical specifications are. I assume DiskEdit has a similar
> > screen. If so please give us the information it displays.
> > 
> Sorry, I cannot give you now the infos because I have broken my 5.25 
> disk drive ( I'm going to buy a new one today ).

  As soon as you have a new drive, I advise you to use NU in /M mode
again, but now only read one sector at the time and look at its contents.

  Start with side 0, cylinder 0, sector 1. Read it and look at it. From
this you can probably determine if it is 512 bytes/sector (normal for
an IBM PC) or less/more (I doubt that the drive can do that, see the
posting of the Disk-RW author.).

  Now try to read the next sectors of the same track. As far as I know
from memory you can do that, while you are in the "Edit/display
information" (or whatever it is called) mode, by pressing Page Down.
When you get an error from NU you know that the sector is not "legal"
(for example sector 9 on a 360KB diskette formatted for only 320KB (8
instead of 9 sectors)). Now you know the number of sectors per track.

  In a similar way you can probably determine the number of tracks on
side 0 and the number of sides used (i.e. if you get errors for all
sectors of cylinder 0, side 1, then the diskette is (probably) single
sided).

Frank Slootweg
Lines: 17