Atlas - DOSPATCH.TXT
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1There are three locations in the DOS where OEMs may want to
2patch in information specific to their installation.
3
4
5The first is the location of the default switch character.
6This character is one byte at DEBUG location 1E5, and is
7set to '/'. To change it to '-' (XENIX compatible)
8do:
9
10        DEBUG MSDOS.SYS
11
12        >e1e5
13        XXXX:01E5   2F.         <at this point give the desired
14                                 new switch character in HEX and
15                                 hit return>
16        >w
17        Writing YYYY Bytes
18        >q
19
20If the byte at 1E5 is not 2F, look around in the immediate
21vacinity (do d1e0) for it. It is the only 2F in that area.
22
23
24The second is the location of the 24 bit user number and the
258 bit OEM number. These values are returned by the GET_VERSION
26system call.
27The user number is 3 bytes starting at
28debug location 683, The OEM number is one byte at debug location
29686. The user number is initialized to 0, the OEM number to -1
30and they immediatly follow the Microsoft Copyright message. If these
31bytes are not zero, look for the four bytes following the
32Copyright message which should be in the vacinity of 683.
33OEMs should request an OEM number from Microsoft if they
34want one of their very own, this prevents selecting one someone
35else already has.
36
37
38The third is the location of the editing template definitions.
39This is a table which defines the two byte edit function keys
40for system call 10 and for EDLIN. This table is at debug location
4133EA, and should start with a 1B. If the byte at 33EA is not
421B, look around in the immediate vacinity. Here is what the
43default table looks like. It is a definition for the Zenith
44Z-19 terminal:
45
46ESCCHAR DB      1BH     ;The Escape character, Nul (0) on IBM
47ESCTAB:
48	DB	"Z"	;5AH Put a ^Z in the template, F6 on IBM
49        DB      "S"     ;53H Copy one char, --> on IBM
50        DB      "V"     ;56H Skip one char, DEL on IBM
51        DB      "T"     ;54H Copy to char, F2 on IBM
52        DB      "W"     ;57H Skip to char, F4 on IBM
53        DB      "U"     ;55H Copy line, F3 on IBM
54        DB      "E"     ;45H Kill line, Not used on IBM
55        DB      "J"     ;4AH Reedit line, F5 on IBM
56        DB      "D"     ;44H Backspace, <-- on IBM
57        DB      "P"     ;50H Toggle insert mode, INS on IBM 
58        DB      "Q"     ;51H Toggle insert mode, INS on IBM 
59        DB      "R"     ;52H Escape char, F7 on IBM
60        DB      "R"     ;52H End of table, must be same as previos character
61
62
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