What is a list of must have reading materials that I need to make the
transition.
C or C++, C++ Prefered but C is fine. Not ready for assembly
programing... yet. LOL

It can be a website, text file, pdf, a book I need to get on ebay.

I have been programming for 15 years, and know how to write basic
applications.
so the languages isn't an issue. I thinking more of the memory
management,
graphics, "GUI", lib (is that the right term for the dos equivelent of
dlls)

What ever you can think of.

                http://www.chebucto.ca/~ak621/DOS/DOS-Pub.html

I was an MS-DOS programmer in the '80's and 90's and also have been a
Windows programmer since the early 90's. In Windows 3.1 I worked with both
Borland and Microsoft C++. I currently work with Microsoft C++ and Qt in
Windows and gcc and Qt in Linux. Other languages of course too but....

Once an ABC+D (ASM, BASIC, C, C++, DOS) programmer always an ABC+D
programmer.

I have programmed for around 30 years in C on Apple II's, Commodore 64's,
CP/M 80  and CP/M 86 systems, MS-DOS systems, most versions of Windows since
3. Also Think C on the Mac 68K and many Unises like AIX, Solaris, SunOS,
HpUX, Xenix, and several Linuxes. I can also still code in fluent DOS MASM
if I want.

Here's my pedigree:

http://en.wikipedia.org/wiki/User:Bill_Buckels

OK, so what I would do were I you:

Ralf Brown's Interrupt List:

http://www.delorie.com/djgpp/doc/rbinter/ix/

The msdos-programmer-faqFAQ

http://www.faqs.org/faqs/msdos-programmer-faq/part1/

X86 Assembly Language FAQ

http://www.faqs.org/faqs/assembly-language/x86/general/part2/section-...

For MS-DOS primarily use int 21h

Freedos is 100% compatible with MS-DOS but nott 100% identical.

http://www.mail-archive.com/freedos-ker...@lists.sourceforge.net/msg02005.html

Tricks of the MS-DOS Masters was one of the books I enjoyed back in the day:

http://www.amazon.com/Waite-Groups-Tricks-MS-DOS-Masters/dp/0672227177

Anyway, I have millions of lines like the following out there. So does
everyone else.

Regards,

Bill

x--- snip ---x

/*
BSVU(C) Copyright Bill Buckels 1990-2009
All Rights Reserved.

A Loader/Viewer for .BSV Saved Text Screen files

Licence Agreement
-----------------

You have a royalty-free right to use, modify, reproduce and
distribute this source code (and/or any modified version)
in any way you find useful, provided you do not compete
with Bill Buckels or his agents, and that you agree that
Bill Buckels has no warranty obligations or liability
whatsoever resulting from any associated loss or damage.

If you do not agree with these terms, remove this source
and all associated files from your computer now.

Description
-----------

This is a companion utility to be used with BSAVED text
images. I hope this code proves informative.

Supported Screen Mode is CGA COLOR TEXT Mode

These .BSV files can be created in the THEDRAW or in
GWBASIC, etc. or aquired using a screen capture program
that saves .BSV files.

This program turns off the cursor, loads the file, waits
for a key press then turns the cursor on and returns the
key value as an exit code. can be used as a slide show
driver or batch menu.

Bill Buckels
bbuck...@mts.net

*/

#include <stdlib.h>
#include <stdio.h>
#include <dos.h>
#include <malloc.h>

#define SCREENSIZE 4000

/* this macro converts a base and offset to a far pointer */
#ifndef MK_FP
#define MK_FP(seg,off) ((char far *)(((long)(seg) << 16) | (off)))
#endif

void main(int argc, char **argv)
{
    FILE *fp;                     /* screen image file ptr */
    unsigned char *psnDataBuf;    /* screen image buffer */
    unsigned char far *lpCrt;     /* screen memory address */
    unsigned uiRetVal = 0,        /* exit code */
             SCREENSEG = 0xb000;  /* initial screen segment */
    union REGS inregs, outregs;   /* regs structures for asm */
    int idx;                      /* scratch counter */

    if (argc < 2) {
      /* put usage help if no args entered on command line */
      puts("BSVU(C) Copyright Bill Buckels 1990-2009");
      puts("All Rights Reserved.");
      puts("Usage is \"BSVU [image.bsv]\"");
    }
    else {
      /* if we can't allocate memory just bail-out */
      if (NULL != (psnDataBuf=malloc(SCREENSIZE))) {
        /* if we can open it... */
        if (NULL != (fp = fopen(argv[1], "rb"))) {
          fread(psnDataBuf,7, 1, fp);
          /* check header for valid image */
          if (psnDataBuf[0] == (unsigned char)'\xfd' &&
              psnDataBuf[1] == (unsigned char)'\x00') {
            /* if valid, read it in! */
            fread(psnDataBuf,SCREENSIZE, 1, fp);
            fclose(fp);
            /* get equipment list from the bios */
            int86(0x11, &inregs, &outregs);
            /* get display type (bits 4 and 5 of ax) */
            if ((outregs.x.ax & 0x30) < 0x30)
              SCREENSEG=0xb800;
            /* point to the screen */
            lpCrt = MK_FP(SCREENSEG,0x0000);
            /* turn cursor off */
            inregs.x.ax = 0x0100;
            inregs.x.cx = 0x2000;
            int86(0x10,&inregs,&outregs);
            /* read the buffer into the screen */
            for(idx=0; idx<SCREENSIZE; idx++)
              lpCrt[idx] = psnDataBuf[idx];
            /* wait for a key press */
            inregs.x.ax = 0x0000;
            inregs.x.dx = 0x0000;
            /* generate int 16h */
            int86(0x16,&inregs,&outregs);
            /* return the low order char */
            uiRetVal = outregs.x.ax&0x00ff;
            /* turn cursor on */
            inregs.x.ax = 0x0100;
            inregs.x.cx = 0x0607;
            int86(0x10,&inregs,&outregs);
          }
          else {
            fclose(fp);
            puts("Invalid Screen Image!");
          }
        }
        else
          perror(argv[1]);
        free(psnDataBuf);
      }
    }
    /* exit with a keypress value if no error */
    exit(uiRetVal);

http://www.teacherschoice.ca/cprog/winbmp30.zip

Source included.

The code below is for a tsr which is assembled with masm then made into a
com using exe2bin. It is a companion to the code I posted previously.
Instead of exe2bin a person should probably use execom today.

Assemble under Windows XP using:

Microsoft (R) Macro Assembler Version 6.14.8444
Copyright (C) Microsoft Corp 1981-1997. All rights reserved.

Microsoft (R) Segmented Executable Linker Version 5.60.339 Dec 5 1994
Copyright (C) Microsoft Corp 1984-1993. All rights reserved.

EXECOM v.0499 Copyright (c) 1988,1989,1999 Thomas G. Hanlin III

Here are the steps:

@echo off
rem MASM.BAT
if not exist %1.asm goto NOTFOUND
c:\masm\ml /c %1.asm
c:\masm\link %1.obj, %1.exe, NUL,,NUL
if exist %1.exe erase %1.obj
c:\masm\execom %1.exe %1.com
goto END
:NOTFOUND
echo %1.ASM was not found!
echo Usage is : MASM [BaseName only - .ASM is assumed]
:END

From my point of view, if a programmer is going to call themselves an MS-DOS
programmer, the minimum I expect is a good working knowledge of interrupts,
and a a good working knowledge of low level adresses like where the screen
lives and how the file system works etc.

The goal here for you would be to take the two programs that I have posted
here and build them. Then capture some DOS screens from 80 column text
programs and display them and actually understand what you have done.

Keep in mind that also in my view a C Windows programmer should know how to
code at the Win32 API level.

Bill

x--- snip ---x

; Program Name    : grabsv.asm
; Author          : bill buckels
; Date            : oct 1993
;;Revised           jul 1996
;;                  removed the installation check
;;                  this causes some pentiums and PS2 compatible bios to
hang

; Purpose         : a memory resident text screen grabber
;                   saves to disk in BSAVED image format

kb_data       equ 60h                       ;keyboard data port
kb_ctrl       equ 61h                       ;keyboard control port
eoi           equ 20h                       ;8259 end-of-interrupt value
int_ctrl_port equ 20h                       ;8259 PIC port
alt_key       equ 8                         ;alt key shift code
period        equ 34h                       ;hot key
_psegoff      equ 22    ;interrupt vector table address for
_poffoff      equ 20    ;the print screen handler vector entries

code          segment para public 'code'
              assume cs:code
              org 100h
begin:        jmp initialize         ;jump to initialization code

_crt         dd      0b8000000h      ;CGA screen address
_vmodeptr    dd      0400049h        ;BIOS display mode record
_installed   dd      0415h           ;Our Signature
pseg         dw      ?               ;Our Printscreen Vector Table Entries
poff         dw      ?
dos_seg      dw      ?               ;Dos Busy ?
indos        dw      ?               ;offset to indos flag
video_seg    dw      0b800h          ;CGA segment

ourpsp       dw      ?               ;save our psp for context switch
theirpsp     dw      ?               ;use their psp to restore context

; The Other ISR's in the chain must be serviced
old_int_9h         label dword       ;old keyboard interrupt vector
old_keyboard_int   dw 2 dup (?)
old_int_1ch        label dword       ;old timer interrupt vector
old_timer_int      dw 2 dup (?)
old_int_28h        label dword       ;old dos idle interrupt vector
old_dos_int        dw 2 dup (?)

hotkeystat         db 0              ;status of keyboard interrupt routine
dos_busy           db 0              ;status of dos
vid_ctr            dw 6              ;length of user defined filename
progress           db 0              ;is a screen save in progress ?
tick_cnt           db 0              ;timer counter

fheader      db      0fdh, 0, 0b8h, 0, 0, 0a0h, 0fh ; bsaved header
footer       db      1ah
buff         db      'S'   ; input field complete with screen attributes
             db      70h
             db      'V'
             db      70h
             db      'G'
             db      70h
             db      'R'
             db      70h
             db      'A'
             db      70h
             db      'B'
             db      70h
             db      '0'
             db      70h
             db      '0'
             db      70h
             db      '.'
             db      70h
             db      'B'
             db      70h
             db      'S'
             db      70h
             db      'V'
             db      70h
             db      ' '
             db      70h
             db         ' ',1fh
             db         'F',1fh
             db         'i',1fh
             db         'l',1fh
             db         'e',1fh
             db         'n',1fh
             db         'a',1fh
             db         'm',1fh
             db         'e',1fh
             db         '?',1fh
             db         ' ',1fh

screenbuffer db      48 dup(?)    ; save the screen under the field

fname                DB 'SVGRAB00.BSV',0    ; filename buffer
          fcnt1      DB '0'                 ; filename counters
          fcnt2      DB '0'
          handle     DW  ?                  ; filehandle

;-------------------------------------------------------
;Resident mainline and ISR routines
;-------------------------------------------------------

; hook the dos idle loop
; reset the dos busy flag if we are called
newdos proc near
       mov dos_busy,0
       jmp old_int_28h
       iret
newdos endp

;check if dos is busy
;ortoo in case the printscreen vectors get messed-up
;put our routine back again
timertick proc near
      sti
      push    ax
      push    cx
      push    dx
      push    bx
      push    sp
      push    bp
      push    si
      push    di
      push    ds
      push    es
      mov     bp,sp
      cmp     progress,0
      jne     inprogress
      push cs             ;put code seg into data seg
      pop ds

      mov     dos_busy,0                  ;test for dos busy?
      mov     ax,dos_seg
      mov     es,ax
      mov     bx,indos
      cmp     BYTE PTR es:[bx],0          ;if not we quietly leave
      je      SKIPDOS
      mov     dos_busy,1
SKIPDOS:
      ;replace the printscreen vectors
      ;every 5- seconds if it has been changed
      inc     tick_cnt
      cmp     tick_cnt,91
      jl      inprogress
      mov     tick_cnt,0

      mov     ax,0
      mov     es,ax

      mov     bx,_psegoff
      mov     ax, WORD PTR es:[bx]
      cmp     ax, pseg
      je      OK_SKIP
      mov     ax,pseg
      mov     WORD PTR es:[bx],ax

OK_SKIP:

      mov     bx,_poffoff
      mov     ax, WORD PTR es:[bx]
      cmp     ax, poff
      je      inprogress
      mov     ax, poff
      mov     WORD PTR es:[bx],ax

inprogress:
      mov     sp,bp
      pop     es
      pop     ds
      pop     di
      pop     si
      pop     bp
      pop     bx
      pop     bx
      pop     dx
      pop     cx
      pop     ax
      cli
      jmp     old_int_1ch
      iret
timertick endp

; when printscreen is pressed, save the screen to disk
printscreen proc near
      sti
      mov progress,1        ; don't bother us... we're busy
      push    ax
      push    cx
      push    dx
      push    bx
      push    sp
      push    bp
      push    si
      push    di
      push    ds
      push    es
      mov     bp,sp

      les     bx,DWORD PTR _vmodeptr      ;are we in text mode 3 or less
      cmp     BYTE PTR es:[bx],3          ;if not we quietly leave
      ja      FALSEXIT
      cmp     dos_busy,0                  ;is dos busy ?
      jne     FALSEXIT

      ;prepare for context switching
      mov ah, 51h
      int 21h
      mov theirpsp,bx
      mov ah, 50h
      mov bx, ourpsp
      int 21h

      push cs                ;put code seg into data seg
      pop  ds

      ;create the user name
      lea dx, fname          ; load the dos name buffer into es:[di]
      mov di,dx
      push ds
      pop es

      lea dx, buff           ; load the field name buffer into ds:[si]
      mov si, dx

doname:

      mov al, BYTE PTR ds:[si]  ;move the field into the dos buffer
      cmp al, 32                ;skip the screen attributes
      je finished               ;Blank ? We are done
      mov  BYTE PTR es:[di],al
      add si,2
      inc di
      jmp doname

finished:

      mov  al,0                 ;Replace the Blank with a NULL terminator
      mov  BYTE PTR es:[di],al
      sub  di,5
      mov  al,fcnt1             ;Embed the Counter Values Into The Name
      mov  BYTE PTR es:[di],al
      dec  di
      mov  al,fcnt2
      mov  BYTE PTR es:[di],al

      push ds                   ;Create/Truncate a Normal File
        lea dx, fname
        xor cx,cx
        mov ah,3ch
        int 21h
      jc MYEXIT
      pop ds
      mov handle,ax       ;save the handle for subsequent operations
      inc fcnt1           ;increment filename
      cmp fcnt1,'9'
      jle DOIT
      mov fcnt1,'0'
      inc fcnt2
      cmp fcnt2,'9'
      jle DOIT
      mov fcnt2,'0'
      jmp DOIT

FALSEXIT:
      jmp     TRUEXIT

DOIT:
      ; write the header
      push ds
        lea dx, fheader
        mov bx,handle
        mov cx,7
        mov ah,40h
        int 21h
      jc MYEXIT
      pop ds

      ; point to the screen
      ; write the body... 4000 bytes
      push ds
        mov bx,handle
        mov ds,video_seg
        xor dx,dx
        mov cx,4000
        mov ah,40h
        int 21h
      jc MYEXIT
      pop ds

      ; write the footer
      push ds
        lea dx, footer
        mov bx,handle
        mov cx,1
        mov ah,40h
        int 21h
      jc MYEXIT
      pop ds

I will post the C code that uses this buffer separately.

Bill

x--- snip ---x

; Program Name    : REAPER.ASM
; Author          : bill buckels
; Date            : July, 1993
; Purpose         : provide a 32K buffer in memory for printed output
;                   use interrupt 17h function FFh

; Uses            : intercept report output passthrough on the
;                   way to the printer and create a copy in memory
;                   which can later be saved to disk using SOWER.EXE

;                   return ax = numberofbytes in buffer
;                   return bx = offset of buffer
;                   return cx = segment of buffer
;                   return dx = numberofbytes in buffer

; calling sequence : call twice. the first call will contain
;                    exactly the same value in ax and dx.
;                    The second call will show ax and cx back to 0.
;                    See Sower.C for more details.

cr            equ  0dh               ;carriage return
lf            equ  0ah               ;line feed

CODE          SEGMENT PARA PUBLIC 'CODE'
              ASSUME CS:CODE
              ORG 100h

BEGIN:        jmp INITIALIZE         ;jump to initialization code

old_int_17h         label dword       ;old printer interrupt vector
old_printer_int     dw 2 dup (?)

bufoff              dw 0              ; segment of buffer
bufseg              dw 0              ; offset of buffer
bufctr              dw 0              ; buffer tail
buffer              db 32767 dup('A')

;-------------------------------------------------------
;Resident mainline and Front-end routine for the printer
;interrupt handler. Execution is vectored here
;when the printer is called
;-------------------------------------------------------

PRINTIT     PROC NEAR
              sti
              push ax          ;save registers
              push bx
              push cx
              push dx
              push si
              push di
              push ds
              push es

              cmp ah, 255          ; function 255 - reset buffer
              je CHANGE_ALL        ; and return address

              cmp ah, 0             ; function 0 - send byte to printer
              jne CHANGE_NOTHING    ; don't bother if not

              cmp bufctr,32767      ; don't bother if buffer is full
              jge CHANGE_NOTHING

              mov si,bufctr
              mov [buffer][si],al ; otherwise move a byte to buffer
              inc bufctr

CHANGE_NOTHING:
              pop es            ;restore the registers
              pop ds
              pop di
              pop si
              pop dx
              pop cx
              pop bx
              pop ax
              jmp old_int_17h   ;goto BIOS printer routine

CHANGE_ALL:
              mov cx,cs                ; cx = buffer seg
              mov bx,offset buffer     ; bx = buffer offset
              mov dx,bufctr            ; dx = byte count
              mov bufctr,0             ; reset the buffer head
              pop es                   ; restore the registers
              pop ds
              pop di
              pop si
              pop ax
              pop ax
              pop ax
              pop ax
              mov ax,dx
              iret
PRINTIT     ENDP

;------------------------------------------------------------
;         RESIDENT PORTION ENDS *** TRANSIENT PORTION STARTS
;------------------------------------------------------------

;------------------------------------------------------------
;initialization message - the requested time limit is inserted here
;------------------------------------------------------------
TITLE$  db 'ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ»',cr,lf
        db 'º  Reaper(C) by Bill Buckels 1993 º',cr,lf
        db 'º  Memory resident printed output º',cr,lf
        db 'º  interception and passthrough   º',cr,lf
        db 'º  Driver Module                  º',cr,lf
        db 'ÈÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍͼ',cr,lf,'$'

SORRY$  db 7,'Error During Loading... Reaper is Already in
Memory!',cr,lf,'$'

;------------------------------------------------------------
;LIST$ writes a string to stdout
;------------------------------------------------------------
LIST$ PROC NEAR
      push ax
      mov ah,9h ; call dos function 9H
      int 21h
      pop ax
      ret
LIST$ ENDP

;----------------------------------------------------------------
;INITIALIZE performs tasks to set the stage for the resident part
;of the program.
;-----------------------------------------------------------------
INITIALIZE    PROC NEAR

;let them know who we are

         lea dx, TITLE$
         call LIST$

;Check memory for ourselves already loaded
;and quit if we are

         mov ah,255
         int 17h
         cmp ax,dx
         jne FIRSTIME
         mov ah,255
         int 17h
         cmp ax,dx
         jne FIRSTIME
         cmp dx,0
         jne FIRSTIME
         lea dx, SORRY$
         call LIST$
         int 20h

FIRSTIME:

;Now save the printer vector and replace it
;with one pointing to the
;code that we will leave behind in memory.

              mov ah,35h                 ;get current interrupt 17H vector
              mov al,17h
              int 21h
              mov old_printer_int,bx       ;save vector offset
              mov old_printer_int[2],es    ;save vector segment

              mov ah,25h                   ;set new vector
              mov al,17h
              lea dx,PRINTIT               ;point it to new handler
              int 21h

;Exit thru INT 27h and reserve enough room
;the offset of TITLE$ is a marker to end of resident code

x--- snip ---x

/* sower.c by bill buckels 1993 */
#include <dos.h>
#include <stdio.h>

char *hello=
"ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ»\n"
"º  SOWER(C) by Bill Buckels 1993  º\n"
"º  Memory resident printed output º\n"
"º  interception and passthrough   º\n"
"º  Data Aquisition Module         º\n"
"ÈÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍͼ\n";

/* this macro converts a base and offset to a far pointer */
#ifndef MK_FP
#define MK_FP(seg,off) ((char far *)(((long)(seg) << 16) | (off)))
#endif

main()
{
    union REGS inregs, outregs;
    unsigned numbytes,numcheck;
    unsigned char far *ptr;
    FILE *fp;

    puts(hello);

    /* call twice */
    inregs.h.ah = 255;
    int86(0x17,&inregs,&outregs);
    numbytes = outregs.x.ax;
    numcheck = outregs.x.dx;
    int86(0x17,&inregs,&outregs);

    if(numbytes!=numcheck)
    {
        puts(" Sorry... Reaper.com not in memory!");
        exit(0);
    }
    if(outregs.x.dx != 0 || outregs.x.ax != 0)
    {
        puts(" Sorry... Reaper.com not in memory!");
        exit(0);

    }

    if(numbytes == 0)
    {
        puts("Sorry... Nothing in Buffer.");
    }
    else
    {
        if((fp=fopen("REAPER.TXT","ab"))==NULL)
        {
            perror(" REAPER.TXT");
        }
        else
        {
            printf("Now appending %d bytes to REAPER.TXT\n",numbytes);
            ptr=MK_FP(outregs.x.cx,outregs.x.bx);
            fwrite((char far *)&ptr[0],numbytes,1,fp);
            fclose(fp);
        }

    }
    puts("Done!");
    exit(0);

You might want to google "Visual C 1.5 torrent" at some point. Over the
years "free" compilers that were available from Microsoft have disappeared
from their websites.

This is not to say that my programs can't be built with other 16 bit
compilers. You could also visit my Aztec C Website and get an MS-DOS C
compiler of an older vintage:

http://www.aztecmuseum.ca/

For assembly language programming, as a starting point you can obtain more
information from The MASM32 Project. Just a note again on converting
assembled EXE files to 16 bit COM files under Windows XP. You will see in a
previous post that I have used EXECOM as the last step in my assembly
language build sequence. EXE2BIN is waytoo DOS version specific.

http://www.masm32.com/

Anyway here's the makefile for the BSVU program:

Bill

x--- snip ---x

all: bsvu.exe

bsvu.obj: bsvu.c
      cl -c -AL -Zp1 bsvu.c

http://www.masm32.com/mlicence.htm

Some links to free C compilers can be found here:

http://www.thefreecountry.com/compilers/cpp.shtml

A good link for free assemblers is:

http://www.thefreecountry.com/compilers/assemblers.shtml