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From: "Patrick Moran" <pmoran22 AT yahoo DOT com>
To: <opendos AT delorie DOT com>
References: <00b801c02814$cc72b3a0$0400000a AT alain-nb> <01d601c04023$ddf751e0$cb881004 AT dbcooper> <005301c04062$9af82420$11fea8c0 AT dell> <001601c041bf$4c924ff0$6f1e0404 AT dbcooper> <000101c041dc$47239a20$11fea8c0 AT dell> <010a01c042dd$202ba230$3d1e0404 AT dbcooper> <017701c04365$41ca2aa0$11fea8c0 AT dell> <00ba01c04442$62576980$eb881004 AT dbcooper> <00c701c044f2$11bc4760$11fea8c0 AT dell>
Subject: Re: DRDOS FDISK
Date: Fri, 3 Nov 2000 10:15:14 -0700
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Reply-To: opendos AT delorie DOT com


----- Original Message -----
From: "Ben A L Jemmett" <ben DOT jemmett AT ukonline DOT co DOT uk>
To: <opendos AT delorie DOT com>
Sent: Thursday, November 02, 2000 10:17 AM
Subject: Re: DRDOS FDISK


> (The two entries for F9 are verbatim).  This coding appears to be the same
> used in the BPB. (I just pulled the first sector of a FAT from a Zip disk
> and the ID there matches the BPB ID).

I also checked some diskettes and they had 29h reguardless of what was in
the first byte of the FAT.

>
> I think a fixed disk is F8h - I've checked this both on the actual HDD in
> this system and on a random Zip disk (the latter has a BPB as follows:)

Yes F8h is used for fixed disks.


> 16AB:0100                                   00 02 04 01 00
> .....
> 16AB:0110  02 00 02 00 00 F8 BC 00-20 00 40 00 00 00 00 00   ........
> .@.....
> 16AB:0120  00 F0 02 00 00 00 29 42-2F E6 1A 52 41 4C 31 20
......)B/..RAL1
                                                      ^^
There is the goold ole 29h----------|

> 16AB:0130  20 20 20 20 20 20 46 41-54 31 36 20 20 20               FAT16
> (This is a copy and paste from DEBUG, using the commandsL 100 3 0 1 and D
> 10B L 33)

> I think Win98 (FAT32) uses a different BPB format - the media descriptor
is
> in the right place, but after that I think the values are laid out
> differently to encode the 32-bit locations.

It probably does. I did look at FAT 32 with the Norton's Disk editor in
maintenance mode, but did not really look that closely at it.

> > [Copy protection]
> > Some even used tracks beyond 39 and DOS would not copy those. AFAIK
there
> > were never any HD disk copy protection, it was only used on DD disks.
> Hmm...  A piece of software I recently disassembled (trying to find out
why
> it would crash on load on this machine) looks for a special track in the
> last cylinder of a disk, and can be installed to a 1.2Mb floppy (the
INSTALL
> program writes the copy-protected track with a special 'installed' flag).

You may be able to overcome this byusing NOGUARD that came with COPYIIPC.
Also COPYIIPC had a NOKEY tsr that would allow a program installed on a HDD
to be run without haiving to insert the floppy.

>
> > This may have changed or may some OEM DOS does it differently, but what
> IBM
> > DOS DISKCOPY did/does is first it formats the disk then it copies all of
> the
> > files. It may or may not copy the BR. But as I recall, if I copied a 3.3
> > formatted diskette with MSDOS 5.0 installed and used 5.0 DISKCOPY, the
BR
> > would show the OEM ID as MSDOS5.0.
> My Amstrad 3.2 DISKCOPY copies the whole lot as a lump of sectors - the
boot
> sector and all.  I know, since the 'Starting out with the PC' instructions
> include 'copy all four system disks supplied', two of which has a DOS Plus
> boot-sector while the others are MS-DOS - the boot sectors are copied
> correctly.  It doesn't even adjust the data in case of a bad sector - so
if
> you copy a good diskette onto one with known bad sectors, the bad sector
> marks in the FAT disappear.

That is an OEM version. OEM versions do many things differently. I gave a
couple of examples in the message you are replying to. That DiSKCOPY would
have wroked fine with the copy protected disk I mentioned.

Pat



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