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