Hard disk type (setting into Bios)

 

Here are some infos I gathered. They have to do it with the bios set disk type. Enjoy...

->A useful program for detecting Disk Type can be DOWNLOAD HERE

1st reference
With the IBM AT and early AT clones, CHS figures never appeared on the screen.
Armed with the CHS figures (and other figures [e.g. WPC]) you would consult the technical manual for your computer.
That would give you a drive type number to enter via your SETUP.EXE

For the first 23 drive types, most clones emulated the 23 drive types defined in the IBM AT (that helped the clone makers to justify their "100% IBM compatible" statement).
Thus try using a drive type using the following IBM AT list:


The first version of the IBM/AT had a ROM BIOS that supported 15 drive types:

Type Cycls Hds WPC Ctrl LZ Sectors Capacity
1 306 4 128 00h 305 17 (10.2Mb)
2 615 4 300 00h 615 17 (20.4Mb)
3 615 6 300 00h 615 17 (30.6Mb)
4 940 8 512 00h 940 17 (62.4Mb)
5 940 6 512 00h 940 17 (46.8Mb)
6 615 4 65535 00h 615 17 (20.4Mb)
7 462 8 256 00h 511 17 (30.7Mb)
8 733 5 65535 00h 733 17 (30.4Mb)
9 900 15 65535 08h 901 17 (112Mb)
10 820 3 65535 00h 820 17 (20.4Mb)
11 855 5 65535 00h 855 17 (35.5Mb)
12 855 7 65535 00h 855 17 (49.7Mb)
13 306 8 128 00h 319 17 (20.3Mb)
14 733 7 65535 00h 733 17 (42.6Mb)
15 0 0 0 00h 0 0 (Reserved)


The second version of the IBM/AT extended the support to 22 different types:

Type Cycls Hds WPC Ctrl LZ Sectors Capacity
22 733 5 300 00h 733 17 (30.4Mb) 
21 733 7 300 00h 732 17 (42.6Mb) 
20 733 5 300 00h 732 17 (30.4Mb) 
19 1024 7 512 00h 1023 17 (59.5Mb) 
18 977 7 65535 00h 977 17 (56.8Mb) 
17 977 5 300 00h 977 17 (40.6Mb) 
16 612 4 0 00h 663 17 (20.3Mb) 


The third and final version of the IBM/AT extended the support to 23 different types:

Type Cycls Hds WPC Ctrl LZ Sectors Capacity
23 306 4 0 00h 336 17 (10.2Mb) 

2nd reference
TYPE Capacity (MB) TYPE Capacity (MB) TYPE Capacity (MB) TYPE Capacity (MB)
0 None 24 20 60 76 73 136
1 10 25 10 61 59 74 114
2 20 26 20 62 93 75 40
3 30 27 40 63 127 76 42
4 62 28 40 64 68 77 68
5 46 29 10 65 93 78 122
6 20 30 20 66 83 79 192
7 30 31 42 67 69 80 262
8 30 32 42 68 85 81 59
9 112 33   69 102 82 93
10 20 34   70 110 83 127
11 35 35   71 119 84 100
12 49 36   72 17
13 20 37  
14 42 38  
15 -- 39  
16 20 40  
17 40 41  
18 56 42  
19 59 43  
20 30 44  
21 42 45  
22 30 46  
23 10 47  

3rd reference
Type Heads Secs/Cyl Cylinders Pre-comp L-zone Capacity (Mb)
1 4 17 306 128 305 10
2 4 17 615 300 615 21
3 6 17 615 300 615 32
4 8 17 940 512 940 65
5 6 17 940 512 940 65
6 4 17 615 no 615 21
7 8 17 462 256 511 32
8 5 17 733 no 733 31
9 15 17 900 no 901 117
10 3 17 820 no 820 21
11 5 17 855 no 855 37
12 7 17 855 no 855 52
13 8 17 306 128 319 21
14 7 17 733 no 733 44
16 4 17 612 all 663 21
17 5 17 977 300 977 42
18 7 17 977 no 977 59
19 7 17 1024 512 1023 62
20 5 17 733 300 732 31
21 7 17 733 300 732 44
22 5 17 733 300 733 31
23 4 17 306 all 336 10
24 5 17 977 no 976 42
26 7 17 1024 no 1023 62
27 11 17 1024 no 1023 98
28 15 17 1024 no 1023 133
29 8 17 1024 no 1023 71
30 11 17 1024 no 1023 98
32 9 17 925 no 926 72
33 10 17 1024 no 1023 89
34 12 17 1024 no 1023 106
35 13 17 1024 no 1023 115
36 14 17 1024 no 1023 124
37 2 17 1024 no 1023 17
38 16 17 1024 no 1023 142
40 6 17 820 no 820 42
41 5 17 1024 1024 1023 44
42 8 17 615 512 615 42
43 7 17 1186 no 1186 72



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