Test image for an 8" drive?

All questions about how to use KryoFlux go here.
baford
Posts: 14
Joined: Sun Jun 06, 2021 9:43 pm

Re: Test image for an 8" drive?

Post by baford »

mr.vince wrote: Thu Jun 10, 2021 10:33 am
baford wrote: Wed Jun 09, 2021 9:08 pm remus:floppies bret$ dtc -m1 -ffloppy_00.0.raw -i -ftest.img -v360 -z3 -i4 -l8
Please don't just pour full logs into threads, it makes them unreadable. Please use the CODE formatting, it's way easier to read. Thanks! I already fixed it for you.
Noted, and thanks for the tip. :-)
baford
Posts: 14
Joined: Sun Jun 06, 2021 9:43 pm

Re: Test image for an 8" drive?

Post by baford »

SomeGuy wrote: Thu Jun 10, 2021 4:21 pm
Disk 10 has 26 128 byte sectors FM (single density) tracks 0-76 on head 0, then 8 1024 byte sectors MFM (double density) tracks 0-76 on head 1. I would assume this disk was re-formatted on a single sided system, and the contents of head 1 are just leftover.
Thanks for the tip. :-) I tried that, and looked at the results...

dtc -m1 -fimage_ -i -ftest.img -g0 -v360 -z0 -i3 -l8
Side 0 (FM) had an assembly code listing from something called "SPELLBINDER."

dtc -m1 -fimage_ -i -ftest.img -g1 -v360 -z3 -i4 -l8
Side 1 (MFM) had text from /usr/games/trek.

A very interesting disk. :D
Note that there there is no "high density" and "low density" with 8" drives. They are all 500kbs, 360RPM. From the perspective of an IBM PC or Kryoflux, this is always "high density".

8" Disks, however, may use FM encoding (single density) or MFM encoding (double density). There are both written at 500kbps.

If "disk1 - take two" was supposed to be the disk that was written back, then you selected the wrong steam file and wrote back one of the other dumps (which contains noise, the result of which is like making a photo copy of a photo copy, the result may not be completely readable).
Thanks for the info. I'm new to this and didn't know some of that.

-Bret.

p.s. I replied to brightcaster about the problem I'm having with disk1. In summary, I tried to reload a disk with its original stream, which does decode correctly, and when I extracted it the contents of the extracted disk are garbled and only partly resemble the original contents. There is some of the correct data in there, but it is noisy as you say. These were the commands I used:

Extracting an image from the original stream. This works correctly:
dtc -m1 -fdisk1_ -i -ftest.img -e76 -v360 -z3 -i4 -l8

Writing that stream to the diskette:
dtc -fdisk1_ -w -we2

Extraction:
dtc -ftest_ -i0

Processing:
dtc -m1 -ftest_ -i -ftest.img -e76 -v360 -z3 -i4 -l8

Test.img is a mess.

I'm going to try writing other things to that diskette and testing them out. I don't know what's wrong, but that's why I'm here. :-)

Thanks again,

Bret.
brightcaster
Posts: 401
Joined: Fri Nov 08, 2013 10:48 pm

Re: Test image for an 8" drive?

Post by brightcaster »

IFW wrote: Tue Jun 08, 2021 9:21 am The very first sector has "APOLLO" in it, not sure what logical format/file system is that... could be e.g. a backup archive too, some of those did something similar to ID their own disks quickly.
Could be this machine:

https://www.computerhistory.org/collect ... /102678356

https://en.wikipedia.org/wiki/Apollo/Domain

They did run the DOMAIN operating system:

https://en.wikipedia.org/wiki/Domain/OS

David
baford
Posts: 14
Joined: Sun Jun 06, 2021 9:43 pm

Re: Test image for an 8" drive?

Post by baford »

brightcaster wrote: Thu Jun 10, 2021 9:00 pm
IFW wrote: Tue Jun 08, 2021 9:21 am The very first sector has "APOLLO" in it, not sure what logical format/file system is that... could be e.g. a backup archive too, some of those did something similar to ID their own disks quickly.
Could be this machine:

https://www.computerhistory.org/collect ... /102678356

https://en.wikipedia.org/wiki/Apollo/Domain

They did run the DOMAIN operating system:

https://en.wikipedia.org/wiki/Domain/OS

David
That's right. Here's a label from one of my 8" disks...
Apollo.jpg
baford
Posts: 14
Joined: Sun Jun 06, 2021 9:43 pm

Re: Test image for an 8" drive?

Post by baford »

So now I've taken my original stream for disk1, extracted an image from it and then used HxC to make a fresh KF Stream file set from the raw image file. Then I wrote that fresh set of stream files to the original disk and read it back. I extracted an image from the resulting files. There are still a few errors, but the results are much better now.

Code: Select all

remus:temp bret$ dtc -m1 -fimage_ -i -ftemp.img -e76 -v360 -z3 -i4 -l8
KryoFlux DiskTool Console, v3.00_OSX_x86-64, uiv.1, May 21 2021, 22:19:58
(c) 2009-2021 KryoFlux Products & Services Ltd.
Developed by The Software Preservation Society, www.softpres.org
Licensed for private, non-commercial use only.

Stream file: image_

00.0    : MFM: OK, trk: 000, sec: 8
00.1    : MFM: OK, trk: 000, sec: 8
01.0    : MFM: OK, trk: 001, sec: 8
01.1    : MFM: OK, trk: 001, sec: 8
02.0    : MFM: OK, trk: 002, sec: 8
02.1    : MFM: OK, trk: 002, sec: 8
03.0    : MFM: OK, trk: 003, sec: 8
03.1    : MFM: OK, trk: 003, sec: 8
04.0    : MFM: OK, trk: 004, sec: 8
04.1    : MFM: OK, trk: 004, sec: 8
05.0    : MFM: OK, trk: 005, sec: 8
05.1    : MFM: OK, trk: 005, sec: 8
06.0    : MFM: OK, trk: 006, sec: 8
06.1    : MFM: OK, trk: 006, sec: 8
07.0    : MFM: OK, trk: 007, sec: 8
07.1    : MFM: OK, trk: 007, sec: 8
08.0    : MFM: OK, trk: 008, sec: 8
08.1    : MFM: OK, trk: 008, sec: 8
09.0    : MFM: OK, trk: 009, sec: 8
09.1    : MFM: OK, trk: 009, sec: 8
10.0    : MFM: OK, trk: 010, sec: 8
10.1    : MFM: OK, trk: 010, sec: 8
11.0    : MFM: OK, trk: 011, sec: 8
11.1    : MFM: OK, trk: 011, sec: 8
12.0    : MFM: OK, trk: 012, sec: 8
12.1    : MFM: OK, trk: 012, sec: 8
13.0    : MFM: OK, trk: 013, sec: 8
13.1    : MFM: OK, trk: 013, sec: 8
14.0    : MFM: OK, trk: 014, sec: 8
14.1    : MFM: OK, trk: 014, sec: 8
15.0    : MFM: OK, trk: 015, sec: 8
15.1    : MFM: OK, trk: 015, sec: 8
16.0    : MFM: OK, trk: 016, sec: 8
16.1    : MFM: OK, trk: 016, sec: 8
17.0    : MFM: OK, trk: 017, sec: 8
17.1    : MFM: OK, trk: 017, sec: 8
18.0    : MFM: OK, trk: 018, sec: 8
18.1    : MFM: OK, trk: 018, sec: 8
19.0    : MFM: OK, trk: 019, sec: 8
19.1    : MFM: OK, trk: 019, sec: 8
20.0    : MFM: OK, trk: 020, sec: 8
20.1    : MFM: OK, trk: 020, sec: 8
21.0    : MFM: OK, trk: 021, sec: 8
21.1    : MFM: OK, trk: 021, sec: 8
22.0    : MFM: OK, trk: 022, sec: 8
22.1    : MFM: OK, trk: 022, sec: 8
23.0    : MFM: OK, trk: 023, sec: 8
23.1    : MFM: OK, trk: 023, sec: 8
24.0    : MFM: OK, trk: 024, sec: 8
24.1    : MFM: OK, trk: 024, sec: 8
25.0    : MFM: OK, trk: 025, sec: 8
25.1    : MFM: OK, trk: 025, sec: 8
26.0    : MFM: OK, trk: 026, sec: 8
26.1    : MFM: OK, trk: 026, sec: 8
27.0    : MFM: OK, trk: 027, sec: 8
27.1    : MFM: OK, trk: 027, sec: 8
28.0    : MFM: OK, trk: 028, sec: 8
28.1    : MFM: OK, trk: 028, sec: 8
29.0    : MFM: OK, trk: 029, sec: 8
29.1    : MFM: OK, trk: 029, sec: 8
30.0    : MFM: OK, trk: 030, sec: 8
30.1    : MFM: OK, trk: 030, sec: 8
31.0    : MFM: OK, trk: 031, sec: 8
31.1    : MFM: OK, trk: 031, sec: 8
32.0    : MFM: OK, trk: 032, sec: 8
32.1    : MFM: OK, trk: 032, sec: 8
33.0    : MFM: OK, trk: 033, sec: 8
33.1    : MFM: OK, trk: 033, sec: 8
34.0    : MFM: OK, trk: 034, sec: 8
34.1    : MFM: OK, trk: 034, sec: 8
35.0    : MFM: OK, trk: 035, sec: 8
35.1    : MFM: OK, trk: 035, sec: 8
36.0    : MFM: OK, trk: 036, sec: 8
36.1    : MFM: OK, trk: 036, sec: 8
37.0    : MFM: OK, trk: 037, sec: 8
37.1    : MFM: OK, trk: 037, sec: 8
38.0    : MFM: OK, trk: 038, sec: 8
38.1    : MFM: OK, trk: 038, sec: 8
39.0    : MFM: OK, trk: 039, sec: 8
39.1    : MFM: OK, trk: 039, sec: 8
40.0    : MFM: OK, trk: 040, sec: 8
40.1    : MFM: OK, trk: 040, sec: 8
41.0    : MFM: OK, trk: 041, sec: 8
41.1    : MFM: OK, trk: 041, sec: 8
42.0    : MFM: OK, trk: 042, sec: 8
42.1    : MFM: OK, trk: 042, sec: 8
43.0    : MFM: OK, trk: 043, sec: 8
43.1    : MFM: OK, trk: 043, sec: 8
44.0    : MFM: OK, trk: 044, sec: 8
44.1    : MFM: OK, trk: 044, sec: 8
45.0    : MFM: OK, trk: 045, sec: 8
45.1    : MFM: OK, trk: 045, sec: 8
46.0    : MFM: OK, trk: 046, sec: 8
46.1    : MFM: OK, trk: 046, sec: 8
47.0    : MFM: OK, trk: 047, sec: 8
47.1    : MFM: OK, trk: 047, sec: 8
48.0    : MFM: OK, trk: 048, sec: 8
48.1    : MFM: OK, trk: 048, sec: 8
49.0    : MFM: OK, trk: 049, sec: 8
49.1    : MFM: OK, trk: 049, sec: 8
50.0    : MFM: OK, trk: 050, sec: 8
50.1    : MFM: OK, trk: 050, sec: 8
51.0    : MFM: OK, trk: 051, sec: 8
51.1    : MFM: OK, trk: 051, sec: 8
52.0    : MFM: OK, trk: 052, sec: 8
52.1    : MFM: OK, trk: 052, sec: 8
53.0    : MFM: OK, trk: 053, sec: 8
53.1    : MFM: OK, trk: 053, sec: 8
54.0    : MFM: OK, trk: 054, sec: 8
54.1    : MFM: OK, trk: 054, sec: 8
55.0    : MFM: OK, trk: 055, sec: 8
55.1    : MFM: OK, trk: 055, sec: 8
56.0    : MFM: OK, trk: 056, sec: 8
56.1    : MFM: OK, trk: 056, sec: 8
57.0    : MFM: OK, trk: 057, sec: 8
57.1    : MFM: OK, trk: 057, sec: 8
58.0    : MFM: OK, trk: 058, sec: 8
58.1    : MFM: OK, trk: 058, sec: 8
59.0    : MFM: OK, trk: 059, sec: 8
59.1    : MFM: OK, trk: 059, sec: 8
60.0    : MFM: OK, trk: 060, sec: 8
60.1    : MFM: OK, trk: 060, sec: 8
61.0    : MFM: OK, trk: 061, sec: 8
61.1    : MFM: OK, trk: 061, sec: 8
62.0    : MFM: OK, trk: 062, sec: 8
62.1    : MFM: OK, trk: 062, sec: 8
63.0    : MFM: <error>, trk: 063, sec: 8, bad: 5, *H +1
63.0    : Bad sector found
63.0    : Read operation failed
63.1    : MFM: OK, trk: 063, sec: 8
64.0    : MFM: OK, trk: 064, sec: 8
64.1    : MFM: OK, trk: 064, sec: 8
65.0    : MFM: <error>, trk: 065, sec: 8, bad: 4, *H +1
65.0    : Bad sector found
65.0    : Read operation failed
65.1    : MFM: OK, trk: 065, sec: 8
66.0    : MFM: OK, trk: 066, sec: 8
66.1    : MFM: OK, trk: 066, sec: 8
67.0    : MFM: <error>, trk: 067, sec: 8, bad: 5
67.0    : Bad sector found
67.0    : Read operation failed
67.1    : MFM: OK, trk: 067, sec: 8
68.0    : MFM: <error>, trk: 068, sec: 8, bad: 1
68.0    : Bad sector found
68.0    : Read operation failed
68.1    : MFM: OK, trk: 068, sec: 8
69.0    : MFM: <error>, trk: 069, sec: 8, bad: 1
69.0    : Bad sector found
69.0    : Read operation failed
69.1    : MFM: OK, trk: 069, sec: 8
70.0    : MFM: OK, trk: 070, sec: 8
70.1    : MFM: OK, trk: 070, sec: 8
71.0    : MFM: <error>, trk: 071, sec: 8, bad: 1, *H +1
71.0    : Bad sector found
71.0    : Read operation failed
71.1    : MFM: OK, trk: 071, sec: 8
72.0    : MFM: OK, trk: 072, sec: 8
72.1    : MFM: OK, trk: 072, sec: 8
73.0    : MFM: OK, trk: 073, sec: 8
73.1    : MFM: OK, trk: 073, sec: 8
74.0    : MFM: OK, trk: 074, sec: 8
74.1    : MFM: OK, trk: 074, sec: 8
75.0    : MFM: OK, trk: 075, sec: 8
75.1    : MFM: OK, trk: 075, sec: 8
76.0    : MFM: OK, trk: 076, sec: 8
76.1    : MFM: OK, trk: 076, sec: 8
Maybe that diskette is just worn out, and the analog image I'd originally taken couldn't be written and read back without a ton of issues.
SomeGuy
Posts: 318
Joined: Wed Feb 18, 2015 8:18 pm

Re: Test image for an 8" drive?

Post by SomeGuy »

Glad that worked for you. I was going to suggest reconstituting an image with HxC. I usually export to imagedisk format and re-import, but in this case Imagedisk format won't work because HxC always assumes IMD files are made at 300RPM so the resulting image is only suitable for 300RPM drives, not 360RPM.

My guess is also that the disk is a bit worn. I've archived plenty of disks that were just readable but then had errors when attempting to reformat.

BTW, Spellbinder was a word processor for CP/M. Interesting that is has source code with it. Nice.
baford
Posts: 14
Joined: Sun Jun 06, 2021 9:43 pm

Re: Test image for an 8" drive?

Post by baford »

SomeGuy wrote: Thu Jun 10, 2021 11:12 pm Glad that worked for you. I was going to suggest reconstituting an image with HxC. I usually export to imagedisk format and re-import, but in this case Imagedisk format won't work because HxC always assumes IMD files are made at 300RPM so the resulting image is only suitable for 300RPM drives, not 360RPM.

My guess is also that the disk is a bit worn. I've archived plenty of disks that were just readable but then had errors when attempting to reformat.

BTW, Spellbinder was a word processor for CP/M. Interesting that is has source code with it. Nice.
Thanks. :-) That detail about Spellbinder is interesting, too.

Incidentally, I wrote (yet another) fresh stream to the diskette and back again, and this time it went through without errors. I'm going to retire that diskette for writing and will just leave the poor thing be. It's been through a lot. The label was printed in August of 1982.

-Bret.

Code: Select all

remus:temp bret$ dtc -m1 -ftemp_ -i -ftest.img -e76 -v360 -z3 -i4 -l8
KryoFlux DiskTool Console, v3.00_OSX_x86-64, uiv.1, May 21 2021, 22:19:58
(c) 2009-2021 KryoFlux Products & Services Ltd.
Developed by The Software Preservation Society, www.softpres.org
Licensed for private, non-commercial use only.

Stream file: temp_

00.0    : MFM: OK, trk: 000, sec: 8
00.1    : MFM: OK, trk: 000, sec: 8
01.0    : MFM: OK, trk: 001, sec: 8
01.1    : MFM: OK, trk: 001, sec: 8
02.0    : MFM: OK, trk: 002, sec: 8
02.1    : MFM: OK, trk: 002, sec: 8
03.0    : MFM: OK, trk: 003, sec: 8
03.1    : MFM: OK, trk: 003, sec: 8
04.0    : MFM: OK, trk: 004, sec: 8
04.1    : MFM: OK, trk: 004, sec: 8
05.0    : MFM: OK, trk: 005, sec: 8
05.1    : MFM: OK, trk: 005, sec: 8
06.0    : MFM: OK, trk: 006, sec: 8
06.1    : MFM: OK, trk: 006, sec: 8
07.0    : MFM: OK, trk: 007, sec: 8
07.1    : MFM: OK, trk: 007, sec: 8
08.0    : MFM: OK, trk: 008, sec: 8
08.1    : MFM: OK, trk: 008, sec: 8
09.0    : MFM: OK, trk: 009, sec: 8
09.1    : MFM: OK, trk: 009, sec: 8
10.0    : MFM: OK, trk: 010, sec: 8
10.1    : MFM: OK, trk: 010, sec: 8
11.0    : MFM: OK, trk: 011, sec: 8
11.1    : MFM: OK, trk: 011, sec: 8
12.0    : MFM: OK, trk: 012, sec: 8
12.1    : MFM: OK, trk: 012, sec: 8
13.0    : MFM: OK, trk: 013, sec: 8
13.1    : MFM: OK, trk: 013, sec: 8
14.0    : MFM: OK, trk: 014, sec: 8
14.1    : MFM: OK, trk: 014, sec: 8
15.0    : MFM: OK, trk: 015, sec: 8
15.1    : MFM: OK, trk: 015, sec: 8
16.0    : MFM: OK, trk: 016, sec: 8
16.1    : MFM: OK, trk: 016, sec: 8
17.0    : MFM: OK, trk: 017, sec: 8
17.1    : MFM: OK, trk: 017, sec: 8
18.0    : MFM: OK, trk: 018, sec: 8
18.1    : MFM: OK, trk: 018, sec: 8
19.0    : MFM: OK, trk: 019, sec: 8
19.1    : MFM: OK, trk: 019, sec: 8
20.0    : MFM: OK, trk: 020, sec: 8
20.1    : MFM: OK, trk: 020, sec: 8
21.0    : MFM: OK, trk: 021, sec: 8
21.1    : MFM: OK, trk: 021, sec: 8
22.0    : MFM: OK, trk: 022, sec: 8
22.1    : MFM: OK, trk: 022, sec: 8
23.0    : MFM: OK, trk: 023, sec: 8
23.1    : MFM: OK, trk: 023, sec: 8
24.0    : MFM: OK, trk: 024, sec: 8
24.1    : MFM: OK, trk: 024, sec: 8
25.0    : MFM: OK, trk: 025, sec: 8
25.1    : MFM: OK, trk: 025, sec: 8
26.0    : MFM: OK, trk: 026, sec: 8
26.1    : MFM: OK, trk: 026, sec: 8
27.0    : MFM: OK, trk: 027, sec: 8
27.1    : MFM: OK, trk: 027, sec: 8
28.0    : MFM: OK, trk: 028, sec: 8
28.1    : MFM: OK, trk: 028, sec: 8
29.0    : MFM: OK, trk: 029, sec: 8
29.1    : MFM: OK, trk: 029, sec: 8
30.0    : MFM: OK, trk: 030, sec: 8
30.1    : MFM: OK, trk: 030, sec: 8
31.0    : MFM: OK, trk: 031, sec: 8
31.1    : MFM: OK, trk: 031, sec: 8
32.0    : MFM: OK, trk: 032, sec: 8
32.1    : MFM: OK, trk: 032, sec: 8
33.0    : MFM: OK, trk: 033, sec: 8
33.1    : MFM: OK, trk: 033, sec: 8
34.0    : MFM: OK, trk: 034, sec: 8
34.1    : MFM: OK, trk: 034, sec: 8
35.0    : MFM: OK, trk: 035, sec: 8
35.1    : MFM: OK, trk: 035, sec: 8
36.0    : MFM: OK, trk: 036, sec: 8
36.1    : MFM: OK, trk: 036, sec: 8
37.0    : MFM: OK, trk: 037, sec: 8
37.1    : MFM: OK, trk: 037, sec: 8
38.0    : MFM: OK, trk: 038, sec: 8
38.1    : MFM: OK, trk: 038, sec: 8
39.0    : MFM: OK, trk: 039, sec: 8
39.1    : MFM: OK, trk: 039, sec: 8
40.0    : MFM: OK, trk: 040, sec: 8
40.1    : MFM: OK, trk: 040, sec: 8
41.0    : MFM: OK, trk: 041, sec: 8
41.1    : MFM: OK, trk: 041, sec: 8
42.0    : MFM: OK, trk: 042, sec: 8
42.1    : MFM: OK, trk: 042, sec: 8
43.0    : MFM: OK, trk: 043, sec: 8
43.1    : MFM: OK, trk: 043, sec: 8
44.0    : MFM: OK, trk: 044, sec: 8
44.1    : MFM: OK, trk: 044, sec: 8
45.0    : MFM: OK, trk: 045, sec: 8
45.1    : MFM: OK, trk: 045, sec: 8
46.0    : MFM: OK, trk: 046, sec: 8
46.1    : MFM: OK, trk: 046, sec: 8
47.0    : MFM: OK, trk: 047, sec: 8
47.1    : MFM: OK, trk: 047, sec: 8
48.0    : MFM: OK, trk: 048, sec: 8
48.1    : MFM: OK, trk: 048, sec: 8
49.0    : MFM: OK, trk: 049, sec: 8
49.1    : MFM: OK, trk: 049, sec: 8
50.0    : MFM: OK, trk: 050, sec: 8
50.1    : MFM: OK, trk: 050, sec: 8
51.0    : MFM: OK, trk: 051, sec: 8
51.1    : MFM: OK, trk: 051, sec: 8
52.0    : MFM: OK, trk: 052, sec: 8
52.1    : MFM: OK, trk: 052, sec: 8
53.0    : MFM: OK, trk: 053, sec: 8
53.1    : MFM: OK, trk: 053, sec: 8
54.0    : MFM: OK, trk: 054, sec: 8
54.1    : MFM: OK, trk: 054, sec: 8
55.0    : MFM: OK, trk: 055, sec: 8
55.1    : MFM: OK, trk: 055, sec: 8
56.0    : MFM: OK, trk: 056, sec: 8
56.1    : MFM: OK, trk: 056, sec: 8
57.0    : MFM: OK, trk: 057, sec: 8
57.1    : MFM: OK, trk: 057, sec: 8
58.0    : MFM: OK, trk: 058, sec: 8
58.1    : MFM: OK, trk: 058, sec: 8
59.0    : MFM: OK, trk: 059, sec: 8
59.1    : MFM: OK, trk: 059, sec: 8
60.0    : MFM: OK, trk: 060, sec: 8
60.1    : MFM: OK, trk: 060, sec: 8
61.0    : MFM: OK, trk: 061, sec: 8
61.1    : MFM: OK, trk: 061, sec: 8
62.0    : MFM: OK, trk: 062, sec: 8
62.1    : MFM: OK, trk: 062, sec: 8
63.0    : MFM: OK, trk: 063, sec: 8
63.1    : MFM: OK, trk: 063, sec: 8
64.0    : MFM: OK, trk: 064, sec: 8
64.1    : MFM: OK, trk: 064, sec: 8
65.0    : MFM: OK, trk: 065, sec: 8
65.1    : MFM: OK, trk: 065, sec: 8
66.0    : MFM: OK, trk: 066, sec: 8
66.1    : MFM: OK, trk: 066, sec: 8
67.0    : MFM: OK, trk: 067, sec: 8
67.1    : MFM: OK, trk: 067, sec: 8
68.0    : MFM: OK, trk: 068, sec: 8
68.1    : MFM: OK, trk: 068, sec: 8
69.0    : MFM: OK, trk: 069, sec: 8
69.1    : MFM: OK, trk: 069, sec: 8
70.0    : MFM: OK, trk: 070, sec: 8
70.1    : MFM: OK, trk: 070, sec: 8
71.0    : MFM: OK, trk: 071, sec: 8
71.1    : MFM: OK, trk: 071, sec: 8
72.0    : MFM: OK, trk: 072, sec: 8
72.1    : MFM: OK, trk: 072, sec: 8
73.0    : MFM: OK, trk: 073, sec: 8
73.1    : MFM: OK, trk: 073, sec: 8
74.0    : MFM: OK, trk: 074, sec: 8
74.1    : MFM: OK, trk: 074, sec: 8
75.0    : MFM: OK, trk: 075, sec: 8
75.1    : MFM: OK, trk: 075, sec: 8
76.0    : MFM: OK, trk: 076, sec: 8
76.1    : MFM: OK, trk: 076, sec: 8

Enjoy your shiny new disk image!
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brightcaster
Posts: 401
Joined: Fri Nov 08, 2013 10:48 pm

Re: Test image for an 8" drive?

Post by brightcaster »

Since nobody knows how the floppies have been stored over the decades, there could be small residues of mold on the surface, which are worn off a little more with each read-write process.

It happens more often that floppies give very bad results on the first attempt and then show fewer errors on each new attempt.

Because of the great hysteresis when changing magnetism (the floppies magnetic layer is extra hard magnetic), there are significantly greater losses when writing than when reading (if the head is not completely on the surface)!

David
baford
Posts: 14
Joined: Sun Jun 06, 2021 9:43 pm

Re: Test image for an 8" drive?

Post by baford »

brightcaster wrote: Fri Jun 11, 2021 8:43 am Since nobody knows how the floppies have been stored over the decades, there could be small residues of mold on the surface, which are worn off a little more with each read-write process.

It happens more often that floppies give very bad results on the first attempt and then show fewer errors on each new attempt.

Because of the great hysteresis when changing magnetism (the floppies magnetic layer is extra hard magnetic), there are significantly greater losses when writing than when reading (if the head is not completely on the surface)!

David
Thanks for the explanation. You even got me to look up hysteresis. :-) This makes sense, and the experience of getting data off of 35-40 year old floppies gives me some confidence in eventually getting my old account data off of the two 9-track tapes I have... once I can get the services of a 9-track tape machine.

-Bret.
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