An anonymous source wrote the following back in the late '80s.

Anybody who has ever stayed up nights wondering how the pinout of the option rom socket (M11) in an M100,102 compares to a JADEC standard EPROM like a 27256 can now rest easy.

M100,102
Option ROM
Socket      Desc.     Standard EPROM (27256)

 1          Vcc       28,1
 2          A10       21
 3          A7         3
 4          A6         4
 5          A5         5
 6          A4         6
 7          A3         7
 8          A2         8
 9          A1         9
10          A0        10
11          D0        11
12          D1        12
13          D2        13
14          GND       14
15          D3        15
16          D4        16
17          D5        17
18          D6        18
19          D7        19
20          A11       23
21          OE_       22
22          A13       26
23          N/C       N/C
24          A12        2
25          A9        24
26          A8        25
27          CE_       20
28          A14       27

-eof-