v2.0/bin/DOSPATCH.TXT

   1 There are three locations in the DOS where OEMs may want to
   2 patch in information specific to their installation.
   3
   4
   5 The first is the location of the default switch character.
   6 This character is one byte at DEBUG location 1E5, and is
   7 set to '/'. To change it to '-' (XENIX compatible)
   8 do:
   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
  20 If the byte at 1E5 is not 2F, look around in the immediate
  21 vacinity (do d1e0) for it. It is the only 2F in that area.
  22
  23
  24 The second is the location of the 24 bit user number and the
  25 8 bit OEM number. These values are returned by the GET_VERSION
  26 system call.
  27 The user number is 3 bytes starting at
  28 debug location 683, The OEM number is one byte at debug location
  29 686. The user number is initialized to 0, the OEM number to -1
  30 and they immediatly follow the Microsoft Copyright message. If these
  31 bytes are not zero, look for the four bytes following the
  32 Copyright message which should be in the vacinity of 683.
  33 OEMs should request an OEM number from Microsoft if they
  34 want one of their very own, this prevents selecting one someone
  35 else already has.
  36
  37
  38 The third is the location of the editing template definitions.
  39 This is a table which defines the two byte edit function keys
  40 for system call 10 and for EDLIN. This table is at debug location
  41 33EA, and should start with a 1B. If the byte at 33EA is not
  42 1B, look around in the immediate vacinity. Here is what the
  43 default table looks like. It is a definition for the Zenith
  44 Z-19 terminal:
  45
  46 ESCCHAR DB      1BH     ;The Escape character, Nul (0) on IBM
  47 ESCTAB:
  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 \1a