Read OS-9 Disk

Read floppy disks written under a OS-9 level 1 environment on PC-based hardware.

OS-9 Hardware

Disk were written on a developement system for embedded application system consisting of

19" rack based system (GESPACs GESBUS bus system G-64)
harddisk drive ST-251 (20MByte)
floppy disk drive 5.25"
floppy disk controller WD 1791
- capable of single (FM) and double (MFM) density format
Cards:
- Telex Adapter (self developement)
- EPROM/RAM-Disk, backup battery buffered (self developement)

PC Hardware

Pentium II 233MHz AGP/PCI/ISA mainboard
Adaptec AHA-1542CF
ISA-card, only floppy controller is used, Linux recognises it as "post-1991 82077")
5 1/4" floppy disk drive (NEC, Epson or similar)
ATAPI-CDROM
... to start a CDROM-based Linux distribution like Knoppix 3.4 - systems of this kind may not boot from SCSI-CDROM or even USB stick

BIOS Setup

Onboard floppy controller: disabled

Adaptec AHA-1542CF

Floppy controller:
Sometimes an add-on floppy card will have a 765-compatible floppy controller that supports FM. The Adaptec AHA1542CF SCSI hard disk controller includes a floppy disk controller on the same card that supports FM and works with both 300 RPM and 360 RPM drives; so do some other Adaptec cards. This card is easy to use; you just plug it into any spare ISA slot and disable your motherboard FDC.
Card setup (switches):
- 1: off (open) Termination Software controlled
- 2-4: off-off-offIO Adresse 330h
- 5: off Floppy enable
- 6-8: on-on-off BIOS Adress D0000h

Ctrl-A (SCSISelect) card BIOS settings:
- BIOS Information:
  - Revision: 2.02
  - Base Address: D0000h
- Firmware Information:
  - Revision: B.0
  - Checksum: A223h
- !Host Adapter Interrupt Channel: 10
- !Host Adapter DMA Channel: 7
- Host Adapter SCSI ID: 7

Advanced Configuration Options
- Floppy Controller I/O Port 3F0-3F7
- INT 19h Support: ENABLE
- everthing else: ENABLE
- Support Removeable Disks Under BIOS as Fixed Disks: D

booting and OS support

Booting with a Linux live CD:

Knoppix 3.4 (Kernel 2.4)
Boot prompt:

 knoppix noscsi

This is needed if the boot procedure seems to hang because the aha1542.o module probing take a lot of time ...

Software

[fdutils] (included on Knoppix distros)
needed commands:
- fdrawcmd (directly read sectors and tracks)
- floppycontrol (initialize/reset the controller)
[Enhanced os9disk software] from JohannKlasek [download]
(supports FM tracks, bugfixes - see changes below)
- based on [Original os9disk software] from Bob van der Poel [download]
- Changes against original version (dated from 2006):
  - Fixed: (os9disk) Memory leaks, handling deleted objects, dateformat, host file changetime
  - Added: (os9read, os9guess) Support for single density tracks (additional tool tr0 to read these tracks)
  - Added: (sector0) Tool for analysing sector 0 (LSN0) in detail
  - Changed: (Readme) some details about PC hardware, updates regarding above changes

Extracting Data

Try to guess the format of the first track (for drive 1, without search for sync identification):

 ./os9gues -c -1

Copy the whole disk into a image with ...

 ./os9read

... giving following dialog:

  Read OS9 Disk Read Utility
  By Bob van der Poel
  And Johann Klasek

  Select the disk format/drive combination
  0. COCO OS9 40/18 DS
  1. MM1 80/36 DS
  2. MM1 80/33 DS
  3. Univeral 80/16 DS
  4. Coco 35/18 Doublestep
  5. Coco 80/18 Doublestep
  6. DD 80/16, DS, Track0/Side0? FM (single density)

 Enter format: 6
 Floppy drive (0,1,2,3): 1
 Prepare the floppy in /dev/fd1 and enter the name of an
 image file. If the file exists it will be overwritten: d1

The images is now stored in file d1.

Analyse an image or a partial image ...

 # read sector 0 of an imagefile and show the parameters ...
 ./sector0 d1

sector0 provides a bunch of more details as os9disk!

Get the files out of the image ...

 # show directory recursively (short style)
 ./os9disk d1

 # show directory recursively (long style)
 ./os9disk -l d1

 # extract all files into directory d1_files/ ...
 mkdir d1_files
 ./os9disk -x -d d1_files d1

OS-9DiskRead