claudetools/projects/dataforth-dos/documentation/DOS_BATCH_ANALYSIS.md

DOS 6.22 Boot Sequence and UPDATE.BAT Analysis

Problem Summary

User reports:

1. Manual backup worked: XCOPY /S C:\*.* T:\TS-4R\BACKUP
2. UPDATE.BAT failed to:
   • Detect machine name (TS-4R) when run without parameters
   • Recognize T: drive as available (claims "T: not available")

DOS 6.22 Boot Sequence

Standard DOS 6.22 Boot Process

1. BIOS POST
2. Load DOS kernel (IO.SYS, MSDOS.SYS, COMMAND.COM)
3. Process CONFIG.SYS
   - Load device drivers
   - Set FILES, BUFFERS, etc.
4. Process AUTOEXEC.BAT
   - Set PATH, PROMPT, environment variables
   - Start network client (if configured)
5. User prompt (C:\>)

Network Boot Additions

For DOS network clients (Microsoft Network Client 3.0 or Workgroup Add-On):

CONFIG.SYS:
   DEVICE=C:\NET\PROTMAN.DOS /I:C:\NET
   DEVICE=C:\NET\NE2000.DOS
   DEVICE=C:\NET\NETBEUI.DOS

AUTOEXEC.BAT:
   SET PATH=C:\DOS;C:\NET;C:\
   CALL C:\NET\STARTNET.BAT

STARTNET.BAT:
   NET START
   NET USE T: \\D2TESTNAS\test /YES
   NET USE X: \\D2TESTNAS\datasheets /YES

Environment After Boot

After STARTNET.BAT completes:

• T: mapped to \D2TESTNAS\test
• X: mapped to \D2TESTNAS\datasheets
• Environment variables:
  • COMPUTERNAME may or may not be set (depends on network client version)
  • PATH includes C:\DOS, C:\NET
  • No USERNAME variable in DOS (Windows 95+ feature)

Root Cause Analysis

Issue #1: Machine Name Detection Failure

Problem: UPDATE.BAT cannot identify machine name (TS-4R)

Likely causes:

1. COMPUTERNAME variable not set in DOS

   • DOS 6.22 + MS Network Client 3.0 does NOT set %COMPUTERNAME%
   • This is a Windows 95/NT feature, NOT DOS
   • The batch file is checking for %COMPUTERNAME% which is EMPTY

2. Machine name stored elsewhere:

   • PROTOCOL.INI (network config file)
   • SYSTEM.INI (Windows 3.x if installed)
   • Could be hardcoded in STARTNET.BAT

3. Detection method flawed:

   • Cannot rely on environment variables in DOS
   • Must use different approach (config file, network query, or manual parameter)

Issue #2: T: Drive Detection Failure

Problem: UPDATE.BAT claims "T: not available" when T: IS accessible

Likely causes:

1. Incorrect drive check method:

   REM WRONG - This doesn't work reliably in DOS 6.22:
   IF EXIST T:\ GOTO DRIVE_OK
   
   REM Also wrong - environment variable check:
   IF "%TDRIVE%"=="" ECHO T: not available
   

2. Correct DOS 6.22 drive check:

   REM Method 1: Check for specific file
   IF EXIST T:\NUL GOTO DRIVE_OK
   
   REM Method 2: Try to change to drive
   T: 2>NUL
   IF ERRORLEVEL 1 GOTO NO_T_DRIVE
   
   REM Method 3: Check for known directory
   IF EXIST T:\TS-4R\NUL GOTO DRIVE_OK
   

3. Timing issue:

   • STARTNET.BAT maps T: drive
   • If UPDATE.BAT runs immediately, network might not be fully ready
   • Need small delay or retry logic

Issue #3: DOS 6.22 Command Limitations

Cannot use in DOS 6.22:

• IF /I (case-insensitive comparison) - added in Windows NT/2000
• %ERRORLEVEL% variable - must use IF ERRORLEVEL n syntax
• FOR /F loops - added in Windows 2000
• Long filenames - 8.3 only
• || and && operators - cmd.exe features, not COMMAND.COM

Must use:

• IF ERRORLEVEL n (checks if >= n)
• Case-sensitive string comparison
• GOTO labels for flow control
• CALL for subroutines
• Simple FOR loops only (FOR %%F IN (*.TXT) DO ...)

Detection Strategies

Strategy 1: Parse PROTOCOL.INI for ComputerName

REM Extract computername from C:\NET\PROTOCOL.INI
REM Line format: computername=TS-4R
FOR %%F IN (C:\NET\PROTOCOL.INI) DO FIND "computername=" %%F > C:\TEMP\COMP.TMP
REM Parse the temp file... (complex in pure DOS batch)

Problems:

• FIND output includes filename
• No easy way to extract value in pure batch
• Requires external tools (SED, AWK, or custom .EXE)

Strategy 2: Require Command-Line Parameter

REM UPDATE.BAT TS-4R
IF "%1"=="" GOTO NO_PARAM
SET MACHINE=%1
GOTO CHECK_DRIVE

:NO_PARAM
ECHO ERROR: Machine name required
ECHO Usage: UPDATE machine-name
ECHO Example: UPDATE TS-4R
GOTO END

Pros:

• Simple, reliable
• No parsing needed
• User control

Cons:

• Not automatic
• User must remember machine name

Strategy 3: Hardcode or Use Environment File

REM In AUTOEXEC.BAT:
SET MACHINE=TS-4R

REM In UPDATE.BAT:
IF "%MACHINE%"=="" GOTO NO_MACHINE

Pros:

• Works automatically
• Set once per machine

Cons:

• Must edit AUTOEXEC.BAT per machine
• Requires reboot to change

Strategy 4: Use WFWG computername

If Windows for Workgroups 3.11 is installed:

REM Read from SYSTEM.INI [network] section
REM ComputerName=TS-4R

Still requires parsing.

Strategy 5: Check for Marker File

REM Each machine has C:\MACHINE.ID containing name
IF EXIST C:\MACHINE.ID FOR %%F IN (C:\MACHINE.ID) DO SET MACHINE=%%F

Pros:

• Simple file read
• Easy to set up

Cons:

• Requires creating file on each machine
• FOR loop reads filename, not contents (wrong approach)

Recommended Solution

Best approach: Use AUTOEXEC.BAT environment variable

This is the standard DOS way to set machine-specific configuration.

REM In AUTOEXEC.BAT (one-time setup per machine):
SET MACHINE=TS-4R

REM In UPDATE.BAT:
IF "%MACHINE%"=="" GOTO NO_MACHINE_VAR
IF "%1"=="" GOTO USE_ENV
SET MACHINE=%1

:USE_ENV
REM Continue with backup using %MACHINE%

This supports both:

• Automatic detection via environment variable
• Manual override via command-line parameter

T: Drive Detection Fix

Current (broken) method:

IF "%T%"=="" ECHO T: not available

This checks if environment variable %T% is set, NOT if T: drive exists.

Correct method:

REM Test if T: drive is accessible
T: 2>NUL
IF ERRORLEVEL 1 GOTO NO_T_DRIVE

REM Alternative: Check for NUL device
IF NOT EXIST T:\NUL GOTO NO_T_DRIVE

REM We're on T: drive now, go back to C:
C:
GOTO T_DRIVE_OK

:NO_T_DRIVE
ECHO [ERROR] T: drive not available
ECHO Run STARTNET.BAT to map network drives
GOTO END

:T_DRIVE_OK
REM Continue with backup

Console Output Issues

Problem: DOS screen scrolls too fast, errors disappear

Solutions:

1. Remove |MORE from commands - causes issues in batch files

2. Use PAUSE strategically:

   ECHO Starting backup of %MACHINE%...
   REM ... backup commands ...
   IF ERRORLEVEL 1 GOTO ERROR
   ECHO [OK] Backup completed
   GOTO END
   
   :ERROR
   ECHO [ERROR] Backup failed!
   PAUSE Press any key to continue...
   GOTO END
   
   :END
   

3. Compact output:

   ECHO Backup: %MACHINE% to T:\%MACHINE%\BACKUP
   XCOPY /S /Y /Q C:\*.* T:\%MACHINE%\BACKUP
   IF ERRORLEVEL 4 ECHO [ERROR] Insufficient memory
   IF ERRORLEVEL 2 ECHO [ERROR] User terminated
   IF ERRORLEVEL 1 ECHO [ERROR] No files found
   IF NOT ERRORLEVEL 1 ECHO [OK] Complete
   

Summary of Fixes Needed

1. Machine detection:

   • Add SET MACHINE=TS-4R to AUTOEXEC.BAT
   • UPDATE.BAT checks %MACHINE% first, then %1 parameter

2. T: drive detection:

   • Replace variable check with actual drive test: T: 2>NUL or IF EXIST T:\NUL
   • Add error handling for network not started

3. Console output:

   • Remove |MORE pipes
   • Add PAUSE only on errors
   • Use compact single-line status messages

4. Automatic execution:

   • Add CALL UPDATE.BAT to end of STARTNET.BAT or AUTOEXEC.BAT
   • Run silently if successful, show errors if failed

Next: Create corrected batch files.