Making floppy disks from images.

[Andy Norrie - Scotland.]

I have been trying to get a Digital Research disks from images. File type of VFD works fine but I have been unable to get any IMG files to work. I have tried RAWRITE, SAMDISK and WINIMAGE but winimage says the file is invalid at the point I try to write to the diskette. The other two write just fine but when I tried to boot I get error msg as unable to boot. Nearly all the diskette files available are in IMG format. I cant believe that all these files are "bad" so can anyone give me some tips. The first CP/M I used was 1.4 but I cant remember much about it now !

Thanks, Andy

[Al Kossow]

Post by Andy Norrie - Scotland.
I have been unable to get any IMG files to work. I have tried RAWRITE, SAMDISK and WINIMAGE but winimage

ImageDisk 1.18
http://www.classiccmp.org/dunfield/img/index.htm

[Al Kossow]

Post by Al Kossow

Post by Andy Norrie - Scotland.
I have been unable to get any IMG files to work. I have tried RAWRITE, SAMDISK and WINIMAGE but winimage

ImageDisk 1.18
http://www.classiccmp.org/dunfield/img/index.htm

sorry, I misread "IMG" as "IMD"

[Bill Marcum]

Post by Andy Norrie - Scotland.
I have been trying to get a Digital Research disks from images. File
type of VFD works fine but I have been unable to get any IMG files to
work. I have tried RAWRITE, SAMDISK and WINIMAGE but winimage says
the file is invalid at the point I try to write to the diskette. The
other two write just fine but when I tried to boot I get error msg as
unable to boot. Nearly all the diskette files available are in IMG
format. I cant believe that all these files are "bad" so can anyone
give me some tips. The first CP/M I used was 1.4 but I cant remember
much about it now !
Thanks, Andy

I think Rawrite and Winimage assume that you're writing a disk with 512
bytes per sector and a standard PC low-level format (360k, 720k, 1.2M or
1.4M). I'm not sure what the recommended software is for recreating a
CP/M disk on a PC, but someone on this newsgroup may know.

[Andy Norrie - Scotland.]

Post by Andy Norrie - Scotland.
I have been trying to get a Digital Research disks from images. File type of VFD works fine but I have been unable to get any IMG files to work. I have tried RAWRITE, SAMDISK and WINIMAGE but winimage says the file is invalid at the point I try to write to the diskette. The other two write just fine but when I tried to boot I get error msg as unable to boot. Nearly all the diskette files available are in IMG format. I cant believe that all these files are "bad" so can anyone give me some tips. The first CP/M I used was 1.4 but I cant remember much about it now !
Thanks, Andy

Many thanks, will get my old PC up and running tomorrow and will get back to you here.

Thanks for a very fast response, Andy

[glen herrmannsfeldt]

Post by Andy Norrie - Scotland.
I have been trying to get a Digital Research disks from images.
File type of VFD works fine but I have been unable to get any IMG
files to work.

As well as I understand it, it was common for 8 inch floppies to
come preformatted, usually in SD 128 byte sectors, following
the IBM standard. CP/M, then, often used an interleave table,
specifying which physical sector corresponded to which logical sector.

Later, 5.25in floppies were usually user formatted (later they often
came preformatted for IBM PC standard.) When you (low level) format
the disk, it is easy to write the sector headers interleaved,
removing the need for a sector translate table. In this case, one
could change the inteleave on disk to match the speed of the system
in use.

Seems to me that some 5.25in systems also applied a sector offset
beween tracks to allow for seek delay.

-- glen

[Egan Ford]

Post by Andy Norrie - Scotland.
I have been trying to get a Digital Research disks from images. File type of VFD works fine but I have been unable to get any IMG files to work. I have tried RAWRITE, SAMDISK and WINIMAGE but winimage says the file is invalid at the point I try to write to the diskette. The other two write just fine but when I tried to boot I get error msg as unable to boot. Nearly all the diskette files available are in IMG format. I cant believe that all these files are "bad" so can anyone give me some tips. The first CP/M I used was 1.4 but I cant remember much about it now !
Thanks, Andy

Can you post the IMG files somewhere?

[Katzy]

Hello.

Andy Norrie - Scotland. wrote in message
<42d0590f-7c8b-4058-9943-***@googlegroups.com>...
I have been trying to get a Digital Research disks from images. File type of
VFD works fine but I have been unable to get any IMG files to work. I have
tried RAWRITE, SAMDISK and WINIMAGE but winimage says the file is invalid at
the point I try to write to the diskette. The other two write just fine but
when I tried to boot I get error msg as unable to boot. Nearly all the
diskette files available are in IMG format. I cant believe that all these
files are "bad" so can anyone give me some tips. The first CP/M I used was 1.4
but I cant remember much about it now !

Datapackrat.com has a file to disk (f2d) and disk to file (d2f) utility which
uses IMG filetypes. There is EXTRACT too which only shows the contents of the
disk. Maybe?

Bye, Katzy.

[g***@aol.com]

Post by Katzy
Hello.
Andy Norrie - Scotland. wrote in message
I have been trying to get a Digital Research disks from images. File type of
VFD works fine but I have been unable to get any IMG files to work. I have
tried RAWRITE, SAMDISK and WINIMAGE but winimage says the file is invalid at
the point I try to write to the diskette. The other two write just fine but
when I tried to boot I get error msg as unable to boot. Nearly all the
diskette files available are in IMG format. I cant believe that all these
files are "bad" so can anyone give me some tips. The first CP/M I used was 1.4
but I cant remember much about it now !
Datapackrat.com has a file to disk (f2d) and disk to file (d2f) utility which
uses IMG filetypes. There is EXTRACT too which only shows the contents of the
disk. Maybe?
Bye, Katzy.

I have tried every program suggested without any joy. I am not sure if using the files from a boot disk (now with no boot sector etc) is possible. Can I create a boot disk somehow. Re sectors on disks it was common to have a 6 sector skew. I worked at IBM Greenock and did a lot on PC,s as well as a home grown 8080 and Nascom 2.

Cheers and thanks, Andy

[l***@gmail.com]

Andy,
Were the Original disks from 8" Media or 5 1/4" Media?

My guess is that they were from 8" Floppy's, so you will need to have a 8" Floppy drive to use to copy the image to the media. (You can't just copy the image to any different size media and expect it to boot and work as the original did.)

If you have a Linux LiveCD, you can boot the LiveCD and try to mount and view the contents of the IMG. I'd suggest trying the following commands from a Linux Terminal:

#Mount the IMG from a Linux LiveCD:
$ sudo mkdir /media/floppy1/
$ sudo mount -o loop /path/to/image/imagefile.img /media/floppy1/
$ cd /media/floppy1
$ ls -alt

#Un-mount the IMG:
$ cd ..
$ sudo umount /media/floppy1

If you have a bootable CP/M system, which has the same 8" (or 5 1/4") sized drive as the original IMG, you can do a bit of research on the written image to determine the format.

If you have an older PC you may want to try 22Disk Version 1.44 to see if it will read the format. Should you want to define a new definition, look at the Mar 14 postings for 22Disk & CP/M Diskettes.

Can you post the img file somewhere, so we can have a look at it?


Thanks.

Larry

[glen herrmannsfeldt]

***@gmail.com wrote:

(snip)

Post by l***@gmail.com
Were the Original disks from 8" Media or 5 1/4" Media?
My guess is that they were from 8" Floppy's, so you will need
to have a 8" Floppy drive to use to copy the image to the media.
(You can't just copy the image to any different size media and
expect it to boot and work as the original did.)

You can if the new size supports the same low-level format
as the original. HD 5.25in pretty much matches the 8 inch format,
though it allows for 80 tracks, instead of the 77 for 8 inch.

HD 3.5in is similar, but runs at 300RPM instead of 360RPM, so the
tracks will be longer. Unless the controller times out on the
excess final gap, it should also work. (You might turn the speed
control up to get closer to 360RPM.)

One thing, though. 8 inch drives use a reduced write current on
the inner tracks. 5.25in and 3.5in HD drives use reduced write current
for writing non-HD media. Don't connect the reduced write current line
up to the 8 inch line with the same name. (I believe ground it for
the HD write current.)

First time I tried a 5.25in HD drive on an LSI-11, I started the
low level format, which went fine until it got to track 44, when
it got stuck. The controller turned on reduced write current.
(I might have forgotten the track.)

-- glen

[Fred J. Scipione]

Post by Andy Norrie - Scotland.
I have been trying to get a Digital Research disks from images.
File type of VFD works fine but I have been unable to get any
IMG files to work. I have tried RAWRITE, SAMDISK and WINIMAGE
but winimage says the file is invalid at the point I try to
write to the diskette. The other two write just fine but
when I tried to boot I get error msg as unable to boot.
Nearly all the diskette files available are in IMG format.
I cant believe that all these files are "bad" so can anyone
give me some tips. The first CP/M I used was 1.4 but I cant
remember much about it now !
Thanks, Andy

Andy,

I can offer you several suggestions. Look for CPMTOOLS and
22DISK on the network. You might need to use a hex+ascii dump
utility on the .img files to determine their internal format.

Type '.img' files are actually just 'RAW' binary sector dumps.
The sector size and sequence information are not given within
the .img file, and must be known/determined by other means.
Publishing a list of your .img file names and sizes may allow
someone here to help you find that info. A dump of the first
20K, or so, of a .img file may reveal clues to sector and
track size, skews, directory parameters, file names, etc.

To use 22DISK you may need an actual DOS system (FreeDOS,
etc.), not just a 16 bit Win 32 .cmd shell. From Linux you
might be able to use 'dd' on a properly formatted diskette
(with the right command-line options).

Some CP/M (2.2/3.0) emulators will let you connect a .img
file in place of a floppy. With the proper CBIOS parameters,
the emulator could let you extract files, do raw sector
exams/dumps, etc. from the .img file.

What system are you trying to 'boot' from the resulting
diskettes? Are your floppy drives and the diskette info in
the .img files the same size/type? Are you trying to boot
CP/M-86 from a CP/M-68K data-only disk, etc.? Some DOS
ROM BIOS's will not boot from a CP/M-86 diskette that does
not use the 'AA55' signature at the end of the 1st sector.
A bootable diskette for one system (with its particular set
of hardware and I/O address configuration) probably will
not boot on another system.

You might want to look-up my post on making a bootable
Kaypro diskette, sent to comp.os.cpm on 8/3/2005.

[glen herrmannsfeldt]

Post by Fred J. Scipione

Post by Andy Norrie - Scotland.
I have been trying to get a Digital Research disks from images.
File type of VFD works fine but I have been unable to get any
IMG files to work.

(snip)

Post by Fred J. Scipione
I can offer you several suggestions. Look for CPMTOOLS and
22DISK on the network. You might need to use a hex+ascii dump
utility on the .img files to determine their internal format.
Type '.img' files are actually just 'RAW' binary sector dumps.
The sector size and sequence information are not given within
the .img file, and must be known/determined by other means.
Publishing a list of your .img file names and sizes may allow
someone here to help you find that info. A dump of the first
20K, or so, of a .img file may reveal clues to sector and
track size, skews, directory parameters, file names, etc.

As well as I understand it (not so well) CP/M 2.2 is based on
logical sectors of 128 bytes, even if the physical sectors have
a different size. In that case, the image should not depend on
the physical sector size.

What I don't know about is interleave. As I understand it, the
usual 8 inch CP/M interleaves the sectors, using a system specific
interleave table. If the image file includes interleaved sectors,
it should be restored with the same interleave.

Seems to me better to write image files with the interleave
removed, though.

-- glen

[l***@gmail.com]

Andy,
I installed yaze-ag ver 2.30 on my Debian 7 laptop last night. It's documentation states the following:

6. CP/M disks
==============
CP/M version 1.4 used single-sided single-density 8" floppy disks with
77 tracks of 26 128 byte sectors each. This format and the
arrangement of data within it remained the standard distribution
format for CP/M 2.2, but other formats were now also supported. This
had advantages and disadvantages. Double density, double sided disks,
hard disks, other floppy sizes etc. could be used, but there was no
standard method of determining what the format of a particular disk
was. Tables had to be built into the BIOS which matched the disk in
question.

Yaze does not attempt to access CP/M disks directly. It assumes that
it is accessing a unix file containing a copy of a CP/M disk. The
file can contain either a raw copy of a standard single-sided
single-density disk (with sector skew = 6), or a de-skewed copy of any
format with a descriptive header. The header is recognized when the
file starts with the string "<CPM_Disk>" (a sort of "magic number")........

So, maybe it will be able to read the IMG file you have, after mounting it in yaze.

Have you been able to do a directory listing of the IMG to see what files are on the IMG? If you can get a copy of the files to a Linux directory, they can be imported into yaze. Then you could build from that.

Yaze-ag also has the following program included:

NAME
cdm - CP/M disk manager

SYNOPSIS
cdm file...

DESCRIPTION
cdm gives access to the CP/M disk images used by yaze(1).
With cdm you can create disks, copy files to and from the
Unix file system, list files and erase files from the CP/M
disk.

NOTE: Yaze required a missing dependency of libreadline-dev before it would build.


Larry

[Ole Christensen]

Larry,... it's very nice of You to try to help out,
but both the messages of Yours just add to the confusing
and help nobody,...
don't get me wrong,... test it out Yourself,...!

Post by l***@gmail.com
My guess is that they were from 8" Floppy's, so you will
need to have a 8" Floppy drive to use to copy the image to the media.
(You can't just copy the image to any different size media and expect
it to boot and work as the original did.)
If you have a Linux LiveCD, you can boot the LiveCD and try to mount
and view the contents of the IMG. I'd suggest trying the following
$ sudo mkdir /media/floppy1/
$ sudo mount -o loop /path/to/image/imagefile.img /media/floppy1/

at this point You will get the friendly messages from mount:
'mount: you must specify the filesystem type'
if not,... then I'm sure many here would like to know what Linux LiveCD
You are using to make this 'magic',...?
---snip---

Post by l***@gmail.com
I installed yaze-ag ver 2.30 on my Debian 7 laptop last night.

nice emulator, using it myself, but test it out a bit first,...

---snip---

Post by l***@gmail.com
copy of any
format with a descriptive header. The header is recognized when the
file starts with the string "<CPM_Disk>" (a sort of "magic number")

no 'real' CP/M floppy have this,... (but i wish they had)

Post by l***@gmail.com
So, maybe it will be able to read the IMG file you have, after
mounting it in yaze.

yaze-ag use, as You point out, it's 'own' 'header' of witch starts
"<CPM_Disk>", then,... later,... the description of the image,
sectors, tracks etc,...

yaze-ag's disk images use to have '.ydsk' as 'extender', (not .IMG)

---snip---

Post by l***@gmail.com
NAME
cdm - CP/M disk manager
SYNOPSIS
cdm file...

'cdm DISKSORT.ydsk' witch means cdm works with same kind of
disk image as yaze-ag,... and why not,... it's part of it,...!

You could have more luck with cpmtools:
$ cpmls -d -f ibm-3740 drived.cpm
CPMLDR COM : CPMLDR DOC : CPMLDR SYM : CPMLDR CTL
CPMLDR ASM : HDFMT COM : MEMTEST COM : WS COM
$

drived.cpm come from the z80pack emulator where the first 4
disk, (images), are 'standard' ibm-3740 CP/M images, images of
'real' floppy's,... and use '.cpm' as extender,...
(still not .IMG)

So, until we learn where the OP got this images from or
it is posted somewhere so people here could take a look
we do know nothing,...
<ole>

[g***@aol.com]

Post by Ole Christensen
Larry,... it's very nice of You to try to help out,
but both the messages of Yours just add to the confusing
and help nobody,...
don't get me wrong,... test it out Yourself,...!

Post by l***@gmail.com
My guess is that they were from 8" Floppy's, so you will
need to have a 8" Floppy drive to use to copy the image to the media.
(You can't just copy the image to any different size media and expect
it to boot and work as the original did.)
If you have a Linux LiveCD, you can boot the LiveCD and try to mount
and view the contents of the IMG. I'd suggest trying the following
$ sudo mkdir /media/floppy1/
$ sudo mount -o loop /path/to/image/imagefile.img /media/floppy1/

'mount: you must specify the filesystem type'
if not,... then I'm sure many here would like to know what Linux LiveCD
You are using to make this 'magic',...?
---snip---

Post by l***@gmail.com
I installed yaze-ag ver 2.30 on my Debian 7 laptop last night.

nice emulator, using it myself, but test it out a bit first,...
---snip---

Post by l***@gmail.com
copy of any
format with a descriptive header. The header is recognized when the
file starts with the string "<CPM_Disk>" (a sort of "magic number")

no 'real' CP/M floppy have this,... (but i wish they had)

Post by l***@gmail.com
So, maybe it will be able to read the IMG file you have, after
mounting it in yaze.

yaze-ag use, as You point out, it's 'own' 'header' of witch starts
"<CPM_Disk>", then,... later,... the description of the image,
sectors, tracks etc,...
yaze-ag's disk images use to have '.ydsk' as 'extender', (not .IMG)
---snip---

Post by l***@gmail.com
NAME
cdm - CP/M disk manager
SYNOPSIS
cdm file...

'cdm DISKSORT.ydsk' witch means cdm works with same kind of
disk image as yaze-ag,... and why not,... it's part of it,...!
$ cpmls -d -f ibm-3740 drived.cpm
CPMLDR COM : CPMLDR DOC : CPMLDR SYM : CPMLDR CTL
CPMLDR ASM : HDFMT COM : MEMTEST COM : WS COM
$
drived.cpm come from the z80pack emulator where the first 4
disk, (images), are 'standard' ibm-3740 CP/M images, images of
'real' floppy's,... and use '.cpm' as extender,...
(still not .IMG)
So, until we learn where the OP got this images from or
it is posted somewhere so people here could take a look
we do know nothing,...
<ole>

The disk images are 1.44 if the file size is anything to go by. I have managed to get some of them to a floppy disk (real one)by using COPYQM. there are still some that do not work. The ones that work have a boot sector at 0 while the ones that do not work have x"E5" (format character) from 0 to about x"240".

All the files have come from one of the CP/M archives.

Thanks for all the help. I have found my origional CP/M 2.2 and MP/M 2.0 real paper manuals so when I get some time I will build an MP/M system on a 386 SBC.

Cheers, Andy

[g***@aol.com]

Post by Andy Norrie - Scotland.
I have been trying to get a Digital Research disks from images. File type of VFD works fine but I have been unable to get any IMG files to work. I have tried RAWRITE, SAMDISK and WINIMAGE but winimage says the file is invalid at the point I try to write to the diskette. The other two write just fine but when I tried to boot I get error msg as unable to boot. Nearly all the diskette files available are in IMG format. I cant believe that all these files are "bad" so can anyone give me some tips. The first CP/M I used was 1.4 but I cant remember much about it now !
Thanks, Andy

If any one wants to look at the .IMG files with a problem this is a website with some of them.

www.z80.info

download pc1440.zip

It is under pc1440 on the operating systems sections.

Cheers, Andy

[Peter Dassow]

Post by g***@aol.com

Post by Andy Norrie - Scotland.
I have been trying to get a Digital Research disks from images. File type of VFD works fine but I have been unable to get any IMG files to work. I have tried RAWRITE, SAMDISK and WINIMAGE but winimage says the file is invalid at the point I try to write to the diskette. The other two write just fine but when I tried to boot I get error msg as unable to boot. Nearly all the diskette files available are in IMG format. I cant believe that all these files are "bad" so can anyone give me some tips. The first CP/M I used was 1.4 but I cant remember much about it now !
Thanks, Andy

If any one wants to look at the .IMG files with a problem this is a website with some of them.
www.z80.info
download pc1440.zip
It is under pc1440 on the operating systems sections.

Andy, I can't find such a file at http://www.z80.info/z80os.htm (which
is in fact the URL for the OS section).
May be you refer to another (non z80.info) page ?

Regards
Peter

[Fred J. Scipione]

"Peter Dassow" <***@arcor.de> wrote in message news:52001d0c$0$6548$***@newsspool4.arcor-online.net...
... <snip> ...

Post by Peter Dassow

Post by g***@aol.com
If any one wants to look at the .IMG files with a problem this is a
website with some of them.
www.z80.info
download pc1440.zip
It is under pc1440 on the operating systems sections.

Andy, I can't find such a file at http://www.z80.info/z80os.htm (which
is in fact the URL for the OS section).
May be you refer to another (non z80.info) page ?
Regards
Peter

I think Andy made a slight error. Look under Emulators and I.C.E,
instead.
<http://www.z80.info/z80emu.htm>

[Peter Dassow]

Post by Fred J. Scipione
... <snip> ...

Post by Peter Dassow

Post by g***@aol.com
If any one wants to look at the .IMG files with a problem this is a
website with some of them.
www.z80.info
download pc1440.zip
It is under pc1440 on the operating systems sections.

Andy, I can't find such a file at http://www.z80.info/z80os.htm (which
is in fact the URL for the OS section).
May be you refer to another (non z80.info) page ?
Regards
Peter

I think Andy made a slight error. Look under Emulators and I.C.E,
instead.
<http://www.z80.info/z80emu.htm>

I've found it, thanks. But I didn't find any unusual content in that
"pc1440" zip file. The disk images are compatible with/made for "ZEMU",
and the programs/software in that disk images can be found elsewhere, too...

Regards
Peter

[g***@aol.com]

Post by Peter Dassow

Post by Fred J. Scipione
... <snip> ...

Post by Peter Dassow

Post by g***@aol.com
If any one wants to look at the .IMG files with a problem this is a
website with some of them.
www.z80.info
download pc1440.zip
It is under pc1440 on the operating systems sections.

Andy, I can't find such a file at http://www.z80.info/z80os.htm (which
is in fact the URL for the OS section).
May be you refer to another (non z80.info) page ?
Regards
Peter

I think Andy made a slight error. Look under Emulators and I.C.E,
instead.
<http://www.z80.info/z80emu.htm>

I've found it, thanks. But I didn't find any unusual content in that
"pc1440" zip file. The disk images are compatible with/made for "ZEMU",
and the programs/software in that disk images can be found elsewhere, too...
Regards
Peter

Just saved me some time as I cant remember what the URL was and was about to set up an FTP server. You say it works with ZEMU so if I install it can I write a physical floppy?

Thanks, Andy

[Peter Dassow]

Post by g***@aol.com

Post by Peter Dassow
I've found it, thanks. But I didn't find any unusual content in that
"pc1440" zip file. The disk images are compatible with/made for "ZEMU",
and the programs/software in that disk images can be found elsewhere, too...
Regards
Peter

Just saved me some time as I cant remember what the URL was and was about to set up an FTP server. You say it works with ZEMU so if I install it can I write a physical floppy?
Thanks, Andy

ZEMU is an emulator like MyZ80 or Z80PACK or SIMH/Altair.
I guess inserting and extracting single files with the help of that
emulator is usually no problem. Writing a physical disk is an unusual
task for an emulator. However you have to read the manual/readme of that
"ZEMU" which is also mentioned on the same page pc1440.zip was offered...

Regards
Peter

[e***@gmail.com]

Post by Andy Norrie - Scotland.
I have been trying to get a Digital Research disks from images. File type of VFD works fine but I have been unable to get any IMG files to work. I have tried RAWRITE, SAMDISK and WINIMAGE but winimage says the file is invalid at the point I try to write to the diskette. The other two write just fine but when I tried to boot I get error msg as unable to boot. Nearly all the diskette files available are in IMG format. I cant believe that all these files are "bad" so can anyone give me some tips. The first CP/M I used was 1.4 but I cant remember much about it now !
Thanks, Andy

Firstly I just want to say that I use to support DR concurrent Dos as a product and a reseller. My experience is that DR disks with CDOS were formatted with a special machine that placed a disk hard error on the disk. No standard copy program can copy these disks and the hard error. When booting, the CDOS disk checks for the hard error code returned, the hard error is not interceptable and cannot be changed. The hard error is unique to the type of hard disk error and not just some run of the mill disk error. The value returned for the error is unique and must be verified correctly, any other error such as a bad block etc...will not work and the CDOS will either freeze, lockup or terminate or even return error that the disk is not bootable or that it has been hacked.

The only way to get it to work is to modify the boot routine supplied on the boot disk along with the programs ()that look for the disk hard error code) and substitute the the compared value to a standard soft error value one that has been hacked into the CDOS boot disk routines.

Of course you need to hack it yourself, or get someone to hack it for you. Another way is to modify your machines Boot ROM with another error value rather than the hard error one, so that when a soft disk error is encountered, it reports a hard error value (exactly what CDOS is looking for on the boot disk). However I do not know how this would affect other programs such as disk utilities. Knowledge of INTEL assembly language required.

If it were possible to dump a BOOT rom into ram and use your own modified/hacked BOOT rom image file you could just do this for the initial installation. After installing you could revert back to the standard built in PC ROM.

I tried installing CDOS 3.0.1 in VMware 7.1 and the only way I even got the
the IMD images to work was to first dump them to raw. Then I loaded them in winimage 9 and saved them as .FLP so vmware could read it. It tried to boot to boot it and it started showing initial boot data and CDOS analysis of the PC and then afterwards froze every time. After about 15 seconds of freezing it showed illigal OP instruction at some weird (always changing) system address. And showed a message "Press Any Key to Continue). Unfortunately pressing any key made no difference, Virtual machine stayed frozen. I remember that this was also the case when I tried to copy the CDOS boot disk back in the day. You can copy the disk, no problem. All the programs are there, except for the hard error on the copid disk, and that is the crusial requirement for the CDOS install routines to work. If I remember correctly, the hard error value was 255, that is not the data written on the disk, it is the error number returned by the disk controller, and from what I knew it was the value for a physically damaged sector.

Many successful Commodore C64 copy protected program disks also used this type of protection. You can copy the disk, just not the hard error on it. If you knew exactly were the hard error should be, you can just place a scratch, or pierce the physical copied disk with a needle etc...at that location. I cannot remember how the hard error was placed on the original CDOS boot disks that were manufactured by DR. They may have been scratched, acid etched, pierced (although i never actually saw holes unless they were microscopic? I do not think lasers were used back then.

Of course the freezing scenario could be a VMware issue running CDOS. I have yet to try on a Hardware PC and booting from physical drives etc...for lack of the hardware. Dumping those CP/M disk images to USB floppy will not work, must use normal floppy controller based hardware attached to the PC bus.

I think that if there is a version of CDOS out there that works without hacking, it means the CDOS boot disk routines have already been hacked. Out of the many images I have found of CDOS, and read many online comments, I have yet to determine if someone has successfully installed Digital Research's CDOS multiuser for 386.

If anyone knows of a working version that boots on a PC and can install in VMWARE 7.1 please let me know cause it is an awesome product. You can truely concurrently multitask up to four instances of DOS software and attach ANSII terminals to remote view the screens from, much like VNC. Unfortunately it was not windows compatible, so you could not run windows in a task.

However, if my memory serves me well, there was a version that Digital Research also released that supported a windows version. Or was it that it could run under windows? This was after I stopped supporting the product so I cannot say. If someone knows please speak up :)

Anywho, that's all I can say for now.