Wow, this is interesting Dave. Took one of the "formatted badly" disks
and did a write of your file.
root@beaglebone:~/mfm# ./mfm_write --emulation RD54_A -d3 -c1224 -h15 -s 17
Board revision C detected
Then a read of the disk:
root@beaglebone:~/mfm# ./mfm_read --analyze -e rd.dsk
Board revision C detected
Found drive at select 3
Returning to track 0
Drive RPM 3596.5
Matches count 34 for controller DEC_RQDX3
Header CRC: Polynomial 0x1021 length 16 initial value 0xffff
Sector length 512
Data CRC: Polynomial 0x1021 length 16 initial value 0xffff
Interleave mismatch previous entry 0, 10 was 2 now 0
Number of heads 15 number of sectors 17 first sector 0
Unable to determine interleave. Interleave value is not required
Drive supports buffered seeks (ST412)
Found cylinder 200 expected 1224
Disk has recalibrated to track 0
Stopping end of disk search due to recalibration
Number of cylinders 1224, 159.8 MB
Command line to read disk:
--format DEC_RQDX3 --sectors 17,0 --heads 15 --cylinders 1224
--header_crc 0xffff,0x1021,16,0 --data_crc 0xffff,0x1021,16,0
--sector_length 512 --retries 50,4 --drive 3
Retries failed cyl 0 head 0
Bad sectors on cylinder 0 head 0: 0 1 2
Retries failed cyl 0 head 3
Bad sectors on cylinder 0 head 3: 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Retries failed cyl 0 head 4
Bad sectors on cylinder 0 head 4: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Retries failed cyl 0 head 5
Bad sectors on cylinder 0 head 5: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Retries failed cyl 0 head 6
Bad sectors on cylinder 0 head 6: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Retries failed cyl 0 head 7
Bad sectors on cylinder 0 head 7: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Retries failed cyl 0 head 8
Bad sectors on cylinder 0 head 8: 0 1 2 3 4 5 6 7 8 9 10 11 12H 13 14 15 16
Retries failed cyl 0 head 9
Bad sectors on cylinder 0 head 9: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Retries failed cyl 0 head 10
Bad sectors on cylinder 0 head 10: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Retries failed cyl 0 head 11
Bad sectors on cylinder 0 head 11: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Retries failed cyl 0 head 12
Bad sectors on cylinder 0 head 12: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Retries failed cyl 0 head 13
Bad sectors on cylinder 0 head 13: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
So looks like the disk is either not taking the format or something is
very very wrong. Wonder what happened to all these disks....
C
