Problem 8" disk with complementary format

[Chuck(G)]

Okay, here's the one for the double-sided drive:

BEGIN KRA1  Krause - DSHD 8"
DENSITY MFM, HIGH
CYLINDERS 77 SIDES 2 SECTORS 15,512
SIDE1 0 1,5,9,13,2,6,10,14,3,7,11,15,4,8,12
SIDE2 1 1,5,9,13,2,6,10,14,3,7,11,15,4,8,12
ORDER EAGLE
COMPLEMENT
BSH 4 BLM 15 EXM 0 DSM 560 DRM 127 AL0 0C0H AL1 0 OFS 2
END

Now, the above will work for reading both single and double-sided formats, but if you want a separate one for single-sided:

BEGIN KRA2  Krause - SSHD 8"
DENSITY MFM, HIGH
CYLINDERS 77 SIDES 1 SECTORS 15,512
SIDE1 0 1,5,9,13,2,6,10,14,3,7,11,15,4,8,12
COMPLEMENT
BSH 4 BLM 15 EXM 0 DSM 279 DRM 127 AL0 0C0H AL1 0 OFS 2
END

I did mental arithmetic for the DSM values--they should be close, if not exact.

 

[fritzeflink]

I'm assuming that you are using REAL disks here. Is that so?

Yeas, I have real floppydisk. 1st I make an image with IMD let IMD use the original sides as there are no extra holes made for flipping disks or so.
The floppydisks are in good condition.



If I've an image I make a cdir to see whats on the disk and if there commes an ERROR message.
I read with [3] command of 22disk but even with fctod [image] which is faster.
At the moment I've made all images from the disks I have - but there are more than 100 laying at the owners basement which I will read some times.

 

[fritzeflink]

Okay, here's the one for the double-sided drive:

Thanks - that shows that my thoughts with DRM and AL0 are not so bad.
ldkraemer too send me definitions which are similar (I must look onto the mail) and for the cpmtools too.

At this point there comes a direct question - how does it go that the DPB from the source is so different?
Until now I had good results using the dpb data from a source I could get or find in the image.
I made a post to the owner of the system if he has an picture or a print from SHOW [drive] to see what the CP/M says about the format.

EXAMPLE from MYZ80:

 

[Chuck(G)]

The problem with emulators is that they use blocking, etc. to suit their ends. For example, on my emulator, the following shows for drive C:

   C: Drive Characteristics
65536: 128 Byte Record Capacity
    0: Kilobyte Drive  Capacity
    0: 32  Byte Directory Entries
    0: Checked  Directory Entries
 2048: Records/ Extent
  256: Records/ Block
   36: Sectors/ Track
    0: Reserved Tracks

This is on a 1TB partition. Not even the DOS emulator can deal with that--it shows 2GB, the maximum under DOS. With emulators, you feed CP/M something reasonable, not something that reflects the physical reality.

I go by what's on the disk, the same as I've been doing since 1987, when 22Disk escaped.

(Tidbit here: 22Disk was written because I didn't have an adequate test base of CP/M programs to test 22Nice, running on the V20's 8080 emulation mode. The obvious thing was to read other systems' programs and run them, so why not write a set of utilities to do just that?)

 

[fritzeflink]

This is on a 1TB partition. Not even the DOS emulator can deal with that--it shows 2GB, the maximum under DOS. With emulators, you feed CP/M something reasonable, not something that reflects the physical reality

Yes - thanks for the hint. The above picture was only for reference. Better I should have taken these from SDLTRS or the real system. :

 

[fritzeflink]

I'm learning ...

As I have some floppydisks without showing errors while reading with 22disk I took 2 of them and look with anadisk to see how much blocks are for the directory.
Not truly surprising there are 3 blocks for the directory. Now I speculate again about the source.

 

[Chuck(G)]

Yes, it could be that someone along the way decided to increase the size of the directory. However, if there are no entries in the third block, it's not a problem, at least for reading using the AL0 0C0H definition. Looks like you've got a mongrel batch of floppies, there.

 

[fritzeflink]

a mongrel batch of floppies

 

[fritzeflink]

Thanks all for your help.

reading the floppydisks with 22disk is now working as expectec.

Next I will get a lot of more floppydisks and we hope that we will find the eprom.com for the cpu card.

 

[fritzeflink]

Just a test for fun - 22disk and IMD with OS/2 - does it work ?

Yes - it works. Even you have to look that you didn't kill the timing with some other programs you use during the operation of 22disk or imd.