IBM AT Drive Types

[Tony Duell]

> 
> Hello all,
> 
> Believe it or not, I couldn't find this on google, so I humbly submit
> it here....
> 
> Does anyone have a list of the built-in drive types from the original
> IBM AT?  I'd like the drive number, heads, cyls, and capacity if you

I have a BIOS source listing that gives the hard disk parameter tables. 
It's not the _original_ BIOS (it's the 1985 one), but I think earlier 
ones just defined fewer drive types. Anyway : 

No   Cylinders   Heads    Write Precomp     Landing Zone   Sectors/track
1      306         4        128               306            17
2      615         4        300               615            17
3      615         6        300               615            17
4      940         8        512               940            17
5      940         6        512               940            17
6      615         4        none              615            17
7      462         8        256               511            17
8      733         5        none              733            17
9      900        15        none              901            17
10     820         3        none              820            17
11     855         5        none              855            17
12     855         7        none              855            17
13     306         8        128               319            17
14     733         7        none              733            17
15   ------- RESERVED -- Do not use ----------------------------
16    612          4        all               663            17
17    977          5        300               977            17
18    977          7        none              977            17
19   1024          7        512              1023            17
20    733          5        300               732            17
21    733          7        300               732            17
22    733          5        300               733            17
23    306          4        all               336            17


Guessing what the various drives were is left as an exercise for the 
reader :-)

-tony