help writing bootable Osborne disks from stream files

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brightcaster
Posts: 432
Joined: Fri Nov 08, 2013 10:48 pm

Re: help writing bootable Osborne disks from stream files

Post by brightcaster »

So the problem is with the writing! Very strange indeed!I guess it's the same behavior when booting from drive B (Shift-Tab to change the letter in the boot screen).

The difference between booting and running some programs is that the boot code is on track 0. But I have no idea why your drive should write all tracks fine except track 0. How does track 0 look if you read it back with the kryoflux? Does it read "green" or "bad"?

David
KennyPowers
Posts: 14
Joined: Wed Jun 16, 2021 3:23 am

Re: help writing bootable Osborne disks from stream files

Post by KennyPowers »

Keeping mind that I know next-to-nothing about CP/M and I wasn't born yet when any of these disks were first mastered... :lol:

I'm guessing the system's BIOS tries to boot from specific track(s)/sector(s)...maybe the drive I'm using for writing is having trouble accurately writing to that area of the disk for some reason? It can obviously write to most of the disk since disks I've written are readable (just not bootable) on the Osborne. Also, if the drive had an alignment issue, I doubt I would be able to dump seemingly-valid IMG sector dumps with it. The disks I'm writing to are all previously-used DS/DD disks. I've also tried passing the -we2 switch to DTC when writing with no effect on the results. Unfortunately, this is the only 40-track 360K drive I have. I do have two 80-track, 1.2M drives, but then I don't have a big magnet for degaussing...
KennyPowers
Posts: 14
Joined: Wed Jun 16, 2021 3:23 am

Re: help writing bootable Osborne disks from stream files

Post by KennyPowers »

brightcaster wrote: Thu Jul 15, 2021 6:25 pm So the problem is with the writing! Very strange indeed!I guess it's the same behavior when booting from drive B (Shift-Tab to change the letter in the boot screen).

The difference between booting and running some programs is that the boot code is on track 0. But I have no idea why your drive should write all tracks fine except track 0. How does track 0 look if you read it back with the kryoflux? Does it read "green" or "bad"?

David
Well I'll be dipped...I didn't know about Shift-Tab to swap the drive letters. I did that and every single floppy I've written (both from the known-good RAW files you attached earlier and from my own RAW dumps of various bootable disks I have) booted just fine from drive B. So now I'm wondering what's up with drive A? All of my original disks boot fine from drive A (or B). Disks I write myself only boot from drive B. Both drives were cleaned and lubricated when I restored the machine. Clearly there's both something different between my original disks and ones I've written, and something different between the two drives in the Osborne...

Edit: If I boot from drive B, put one of my written disks (that won't boot from drive A) into drive A, and try to switch to that disk ("b:" from the command line because Shift-Tab switches the logical drive letters), I get a BIOS error:

Code: Select all

BIOS error reading drive B: crc-error, (code=08/01-0000AE020300010C)
So basically, it appears that drive A can't read or boot from my written disks in any way, but it handles my original disks without a problem.
brightcaster
Posts: 432
Joined: Fri Nov 08, 2013 10:48 pm

Re: help writing bootable Osborne disks from stream files

Post by brightcaster »

It's really strange. It could be a creeping drive A alignment problem, where the former owner has rewritten the "original" floppies at a point when the drive was just beginning to show read errors (only slightly disaligned). As a result, the floppies may have remained in an intermediate alignment that drive A and drive B can still read. A perfectly aligned floppy (written by your TEAC or drive B), on the other hand, can no longer be read by drive A today (being heavy disaligned). However, this would require that the write protection has been removed from the original floppies (by cutting a notch for example).

Do you have any known good 5.25 inch floppies other than the Osborne disks (which could be rewritten)? Maybe some MS-DOS floppy disks that are professionally mastered? Would be interesting to see how they read in your TEAC.

It would also be interesting how your "original" floppies read in an 80 track drive. The content of the odd tracks can give a good hint to any disalignment...

David
KennyPowers
Posts: 14
Joined: Wed Jun 16, 2021 3:23 am

Re: help writing bootable Osborne disks from stream files

Post by KennyPowers »

brightcaster wrote: However, this would require that the write protection has been removed from the original floppies (by cutting a notch for example).
The original, professionally mastered system disk I posted a photo of on the last page has not been notched and reads fine in both drives. When dumping it with the TEAC, all tracks are "green". If I dump that disk to stream files and write those stream files back to another disk, then only drive B in the Osborne can read it. Maybe there are minor alignment issues in both the Osborne's drive A and my TEAC that, when combined, cause this issue? Though if I read and write stream files in the same misaligned drive, does it "matter" (if that question makes sense)? Also, I doubt all tracks would show "green" when dumping a known-good disk if the TEAC were misaligned, right? Does that rule out an alignment problem in my TEAC, or is there some other test I should do? I don't want to dump 100 disks with it and then find out all of those stream files are no good. When I calibrate the TEAC with the KryoFlux software, it reports maxtrack=41.
Last edited by KennyPowers on Fri Jul 16, 2021 7:19 pm, edited 1 time in total.
brightcaster
Posts: 432
Joined: Fri Nov 08, 2013 10:48 pm

Re: help writing bootable Osborne disks from stream files

Post by brightcaster »

KennyPowers wrote: Fri Jul 16, 2021 6:14 pm
Also, I doubt all sectors would show "green" when dumping a known-good disk if the TEAC were misaligned, right? Does that rule out an alignment problem in my TEAC, or is there some other test I should do?
[/quote]

Yes, if all tracks show "green" you got a perfect dump! In my opinion it's clearly a matter of drive A....

As I said the only other test I can think of is reading the "original" floppy with a 80 track drive and look at the odd tracks...

But others may have other ideas based on their experience!

David
KennyPowers
Posts: 14
Joined: Wed Jun 16, 2021 3:23 am

Re: help writing bootable Osborne disks from stream files

Post by KennyPowers »

brightcaster wrote: As I said the only other test I can think of is reading the "original" floppy with a 80 track drive and look at the odd tracks...
I just took one of the non-professionally-mastered "original" disks that reads fine in both Osborne drives, but duplicates of it would only read in drive B, and dumped it with an 80-track drive. The scatter plots for all of the even tracks show 3 distinct lines. The scatter plots for all of the odd tracks are just a fog. I checked every track. Is there something else I should look for in the 80-track dump?
brightcaster
Posts: 432
Joined: Fri Nov 08, 2013 10:48 pm

Re: help writing bootable Osborne disks from stream files

Post by brightcaster »

Please boot from drive B and use the COPYSYS command to write a copy of the boot floppy on drive A. Does the floppy written on A this way look the same on the odd tracks?

David
ldkraemer
Posts: 25
Joined: Sat Apr 20, 2013 3:54 am

Re: help writing bootable Osborne disks from stream files

Post by ldkraemer »

Kenny,
I'm assuming you are taking the ose-cpma_td0{00..39}.0.raw files from the .ZIP and trying to write them with the Kryoflux.
When I worked with the Stream.RAW files, I would make a *.IPF file as an intermediate step. Then, I used Keir Frasier's
Disk Utilities to create a Sector Dump (.RAW or .IMG) and wrote that to floppy with Linux's dd command. Linux has
mtools and fdutils packages in the repository that allow you to format the floppy according to the OEM layout for Tracks,
Sectors, and bytes per sector.

The /etc/mediaprm file contains the Definitions:

Code: Select all

# /etc/mediaprm  -  floppy disk parameter table
# NB: this file was formerly named /etc/fdprm.

########################################################################
# Standard linux disk formats. Names are of the form
#  actual media capacity/maximum drive capacity
# (Note: although 5.25" HD drives can format disks at 1.44M, they're listed
#        as 1200 because that's the common maximum size.)

#		size sec/t hds trk stre gap  rate spec1 fmt_gap

"360/360":
 DS DD sect=9

"1200/1200":
 DS HD sect=15

"360/720":
 SS DD sect=9
..
..
..
..
########################################################################
# CP/M formats
#
# the name is constructed as CODsize, where COD identifies the
# brand of the computer having formatted the disk

# Generic CP/M - SSSD 8"

"GEN250":
 SS DD sect=24 dtr=0 fm=1 cyl=77 ssize=128
..
..
..
# Osborne 1 - SSSD 48 tpi 5.25"

"OSB100":
 SS SD sect=10 dtr=1 fm=1 ssize=256

# Osborne 1 - SSDD 48 tpi 5.25"

"OSB200":
 SS DD sect=5 ssize=1KB

# Osborne Executive - SSDD 48 tpi 5.25"

"OSB200":
 SS DD sect=5 ssize=1KB

# Osborne 1 + Osmosis - DSDD 96 tpi 5.25"

"OSB400":
 DS DD sect=10

# Osborne Vixen - DSDD 48 tpi 5.25"

"OSB400":
 DS DD sect=5 ssize=1KB

# Osborne Executive w/Z3 - DSDD 96 tpi 5.25"

"OSB800":
 DS QD sect=5 ssize=1KB
As you can see the OSB Executive layout is SS DD sect=5 ssize=1KB

This also needs to be correct to write the Actual .RAW data file. In Linux the dd command will also write directly to the floppy
dumping the .RAW or .IMG data into the proper sectors.

One other problem exists in that Linux has dropped Floppy Drive support in the updated Kernels. So you must use a previous
version of Ubuntu or Debian that still supports the Floppy's Hardware. I believe that Ubuntu 10.04 and Debian 6.x are about the last
versions that support the floppy. Without installing each version it's hard to know for sure as I haven't found the documentation
about when support was dropped.

With a DOS Computer you should be able to use Imagedisk by Dave Dunfield to write the Floppy. You will have to use the settings
menu to define the floppy's layout. Plus, you will need to test the computers Floppy Disk Controller (FDC) with the included
"TESTFDC.*" program to make sure it will write properly. That is explained in the Documentation for Imagedisk.

This last step seems to be your problem. Another option would be to make a GreaseWeazle and write the floppy with the
GreaseWeazle.


Larry
ldkraemer
Posts: 25
Joined: Sat Apr 20, 2013 3:54 am

Re: help writing bootable Osborne disks from stream files

Post by ldkraemer »

Since you are new to CP/M, remember this key point. Whenever you insert a different floppy into any Floppy Drive,
be sure to do a CONTROL-C to read in the new Directory structure(s) or you will clobber the floppy(s). The CP/M
system has a copy of the directory in memory and if you change the floppy, the system is not updated until the next
warm boot.

Larry
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