Kaypro-10

[xolod79]

David Greetings! I'm already becoming your regular guest! I've had the NEC D5124 disc for two years now. He did not want to blink his heads, I tried to repair him, changed transistor keys, head controls ... facepalm =( But today I was able to read it, but the format is not known. The disk was connected to the controller: WD1002-HDO (Like Kaypro-10) https://retrocmp.de/kaypro/kay-p2_hrdw.htm#hdc But this controller was in a very, rare Labtam 3000 computer, and the program in the controller's rom may have been changed. Please have a look at it:

./mfm_read -a
Board revision B detected
Found drive at select 1
Returning to track 0
Drive RPM 3595.0
0, 0
1, 0
2, 0
3, 0
4, 0
5, 0
6, 0
7, 0
8, 0
9, 0
10, 0
11, 0
12, 0
13, 0
14, 0
15, 0
16, 0
17, 0
18, 0
19, 0
20, 0
21, 0
22, 0
23, 0
24, 0
25, 0
26, 0
27, 0
28, 0
29, 5
30, 3
31, 6
32, 6
33, 2
34, 2
35, 2
36, 2
37, 4
38, 16
39, 1053
40, 15990
41, 25364
42, 26284
43, 10595
44, 714
45, 10
46, 4
47, 4
48, 1
49, 1
50, 3
51, 3
52, 1
53, 2
54, 3
55, 2
56, 1
57, 2
58, 4
59, 2
60, 3
61, 0
62, 2
63, 2
64, 2
65, 0
66, 1
67, 2
68, 0
69, 3
70, 2
71, 5
72, 1
73, 1
74, 1
75, 0
76, 0
77, 4
78, 3
79, 0
80, 1
81, 4
82, 5
83, 2
84, 2
85, 2
86, 3
87, 2
88, 0
89, 0
90, 4
91, 1
92, 4
93, 1
94, 0
95, 2
96, 2
97, 2
98, 1
99, 2
No more peaks in histogram
0, 0
1, 0
2, 0
3, 0
4, 0
5, 0
6, 0
7, 0
8, 0
9, 0
10, 0
11, 0
12, 0
13, 0
14, 0
15, 0
16, 0
17, 0
18, 0
19, 0
20, 0
21, 0
22, 0
23, 0
24, 0
25, 0
26, 0
27, 0
28, 1
29, 3
30, 4
31, 3
32, 6
33, 3
34, 3
35, 3
36, 1
37, 3
38, 23
39, 1187
40, 16593
41, 24404
42, 25849
43, 11184
44, 767
45, 12
46, 1
47, 3
48, 2
49, 3
50, 6
51, 3
52, 1
53, 6
54, 1
55, 3
56, 4
57, 3
58, 1
59, 2
60, 2
61, 1
62, 1
63, 2
64, 3
65, 3
66, 0
67, 3
68, 0
69, 0
70, 3
71, 2
72, 2
73, 4
74, 2
75, 2
76, 1
77, 4
78, 2
79, 2
80, 3
81, 2
82, 0
83, 2
84, 0
85, 2
86, 1
87, 4
88, 0
89, 2
90, 1
91, 2
92, 0
93, 0
94, 0
95, 0
96, 1
97, 1
98, 1
99, 0
No more peaks in histogram

[dgesswein]

Found the issue with reading when trying to read a disk from a Kaypro 10.

You can decode the file with this command line.

mfm_util --tran necd5124-labtam.trans --format Intel_iSBC_214_512B --sectors 17,0 --heads 4 --cylinders 309 --header_crc 0xffff,0x1021,16,0 --data_crc 0xffffffff,0x140a0445,32,6 --ext /tmp/t --ignore_seek_errors

Not enough readable to be useful. Expected 21012 sectors got 9665 good sectors, 11344 bad header, 3 bad data

Looks like the interrupter is misaligned so its actually at track -7 when it thinks its at track 0. Thats the better way to be off.

Also mostly don't see sector 16 but likely that can be fixed.

The big problem is it can only read every other cylinder. Something is going wrong with stepping so heads end up at the wrong location every other step. Either the problem needs to be fixed or stepper externally driven. http://www.pdp8online.com/mfm/microstep/index.shtml

On Sun, Jun 04, 2023 at 10:29:01AM -0700, xolod79 wrote:

David Greetings! I'm already becoming your regular guest! I've had the NEC D5124 disc for two years now. He did not want to blink his heads, I tried to repair him, changed transistor keys, head controls ... facepalm =( But today I was able to read it, but the format is not known. The disk was connected to the controller: WD1002-HDO (Like Kaypro-10) https://retrocmp.de/kaypro/kay-p2_hrdw.htm#hdc Please have a look at it: https://mega.nz/file/u9B1hS5b#57GnX2-C8uIXkv32heYxbymdZHqeExMZczYRQT2cEf8

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