Linuxdoc Linux Questions
Click here to ask our community of linux experts!
Custom Search
Next Previous Contents

5. Remote-Boot Tools Reference Manual

This section provides detailled informations on the use of the tools we developped at the CUI, University of Geneva for this remote-boot configuration.

5.1 BpBatch, MrBatch and MrZip

These three names stand for three variants of the same program, with the following characteristics:

Command Line Arguments

All programs accept the same syntax of arguments. MrBatch and MrZip take them from the command line, while BpBatch look for them in the BOOTP option 155 (decimal). Here is the syntax of the arguments:

        [-x] [-l] [-b] [-v] [-w] [-i] [script-basename]
where: The script-basename is optional. If provided, MrBatch and BpBatch load the file with the .bpb extension, and MrZip loads the file with the .mrz extension. If not provided, MrBatch and MrZip run in interactive mode while BpBatch loads the file with the same basename as the BOOTP Boot file and a .bpb extension.

Syntax rules

The following rules apply when BpBatch parses an input line.

Empty lines are ignored. Lines starting with a sharp (#) are treated as comments and are not interpreted. Lines starting with a column (:) are treated as labels and are not interpreted.

String expressions

Strings are delimited by opening and closing double-quotes:

        "Hello world"
To include double-quotes within a string, quote them using a backslash:
        "I said: \"Hello world\""
Strings can be postfixed with a few operators.
  • The character substitution operator:
            "Hello world"/o=u/      ==      "Hellu wurld"
            "198.76.54.32"/.= /     ==      "198 76 54 32"
    
  • The word selection operator (zero-based):
            "Hello world"{0}        ==      "Hello"
            "198 76 54 32"{1-3}     ==      "76 54 32"
    
  • The substring selection operator (zero-based):
            "Hello world"[4]        ==      "o"
            "Hello world"[4-7]      ==      "o wo"
    
Operators can be chained by postfixing one after the other. For informations about the string length and word count operators, see under "Numerical expressions".
Numerical expressions

Numerical expressions work on 32-bits integer numbers (from -2,147,483,646 to 2,147,483,647). Hexadecimal octal and binary numbers are not understood. Whenever a numerical expression is expected, the following are recognized:

  • A positive or negative integer number
  • An expression in the form (expr1 op expr2) where op can be either +, -, * (multiply), / (divide) or % (modulo) and expr is a numerical expression. Note that EACH operation MUST be enclosed between parenthesis :
            ((3 * 5)+2)             == 17
    
  • The string-length operator (@), followed by a string :
            @"Hello world"          == 11
    
  • The word-count operator (#) followed by a string :
            #"Hello world"          == 2
    
Durations

A few commands expect durations as arguments. Durations are measured in seconds, with a precision of up to a tenth of second:

        Delay 3                 waits for 3 seconds
        Delay 0.3               waits for 3/10 seconds
Colors

Whenever a color is expected, you can either use the numeric value of the color or its symbolic name (case-insensitive). The following colors are recognized

        Black           0
        Blue            1
        Green           2
        Cyan            3
        Red             4
        Magenta         5
        Brown           6
        LightGray       7
        DarkGray        8
        LightBlue       9
        LightGreen     10
        LightCyan      11
        LightRed       12
        LightMagenta   13
        Yellow         14
        White          15
File References

File names are strings. They must therefore always be enclosed between double-quotes. File names are case-sensitive on case-sensitive filesystems, case-insensitive on case-insensitive filesystems. Slash and backslash can be freely used one in place of the other. Do not forget to double backslash since a single backslash is an escape character.

There are two kinds of file references:

  • Direct disk files
  • Foreign files

Direct disk files are referenced using the following notation:

        "{disk:partition}/absolute/filename"
The disk number can be omitted and defaults to zero. For instance, "{:1}/usr/bin" points to /usr/bin assuming there is such a directory on the first partition. Direct file I/O is solely based on our own file access routines (we do not use the operating system).

There are two special partitions. Partition zero corresponds to the hard disk master boot record (MBR) and has a pseudo file-system which let you access the boot code. Partition minus-one (-1) corresponds to the cache filesystem (see below).

Under BpBatch/MrBatch, foreign files correspond to remote files on the TFTP server when the BootProm is available:

        "help.bpb"           is the file help.bpb in the /tftpboot directory
        "gifs/MyImage.gif"   is a file in /tftpboot/gifs
Other TFTP servers can be referenced :
        "198.76.54.32:help.bpb" 
If the other server is behind a gateway :
        "198.70.0.1/198.76.54.31:help.bpb"
One can also specify a specific port for the TFTP connection :
        "198.76.54.32@89:getpasswd/smith"
There can be only one open remote file at a time. If the BootProm is not available, remote files are emulated using the operating system file I/O, but the same restriction apply.

Under MrZip, foreign files correspond to files as seen by the operating system. There is no limitation, and foreign files can be used wherever direct disk files can be. Foreign files are usually faster than direct disk files, because the operating system has more buffers. Foreign files can refer to network files if supported by the operating system.

        "C:\\autoexec.bat"
        "C:/config.sys"
        "/mnt/net/usr"

The Cache Filesystem

In order to reduce network load and to fasten the boot process, disk archives, linux kernels and possibly other files are cached on the hard disk. This disk cache is located at the end of the hard disk, between the last cylinder allocated in the partition table and the last physical cylinder of the disk (out of any allocated partition). There MUST be room between the last partition and the end of the disk if you want the cache filesystem to work. The cache filesystem MUST work if you want to restore a disk image.

The disk cache is organised in a volatile, CRC-validated filesystem : Each directory entry and each 32 KB data block is validated by a 32-bits CRC. Whenever a directory entry or a data block unexpectedly changes, the file is automatically removed from the cache and downloaded again upon the next request.

You can freely access the cache filesystem from within BpBatch, MrBatch and MrZip using direct disk access on the special partition "{:-1}". To see the content of the cache, just type :

        logdir "{:-1}"
If the cache ever gets corrupted and is not automatically cleaned (which should never occurs), you can either type :
        clean -1
(in interactive mode) or hold both shifts down when BpBatch access the cache for the first time.

Special variables

Some variable are initially set and/or have special meanings. Some of them exist within all programs, other are only available under MrZip and other are only available when a BOOTP/DHCP reply has been received.

General variables
  • $Program is set to "BpBatch" within BpBatch, "MrBatch" within MrBatch and "MrZip" within MrZip
  • $Basename is set to the basename of the script on which the batch interpreter was started
  • $HelpFile is the name of the file loaded when Help is invoked. Default: "${Basename}.hlp"
  • $BOOTP-... are variables set from the BOOTP/DHCP reply (see the paragraph on BOOTP/DHCP variables for more details)
  • $DHCP-... are variables set from the DHCP reply (see the paragraph on BOOTP/DHCP variables for more details)
  • $Disks is set to the space-separated list of sizes for each disk. That means, #"$Disks" represent the number of disks and "$Disks"{0} is the size of the first disk
  • $Keypressed is set to the next ready-to-read key available in the keyboard buffer (if available)
  • $LBA controls the use of LBA to access disks > 2Gb. Default: "ON"
  • $FDA controls the use of fast disk access (write accross cylinders). Default: "ON"
  • $VESA controls the use of VESA graphics. Default: "ON" if available
  • $VESA-Modes gives the list of all available VESA modes. The first entry of the list is the default mode, which is used when no parameter is given to InitGraph. Note: if VESA="OFF", this variable is blank
  • $APM is set to "ON" if your computer supports Avanced Power Management. If $APM is "ON", you can use the command PowerOff to turn your computer off. Default: depends on your hardware
  • $Trace controls the display of each command before execution. It also controls the display of file names when creating new archives. Default: "OFF"
  • $AutoShowLog controls the automatic switch to the text log whenever the ESC key is pressed. Default: "ON"
  • $PauseLog controls the pause between each page of log when the log is visible. Default: "ON"
  • $CacheDisk is set to the disk used for caching remote files. Default: empty == 0, the first hard disk
  • $CacheAlways controls the automatic caching of remote files copied, patched or drawn as GIF. Default: "OFF"
  • $CacheNever prevents any file from being cached. Turn this variable on for diskless Linux boot. Default: "OFF"
  • $CacheReserve controls the preventive allocation of 25 percent more space than necessary in the cache partition, to let the files grow. Turn this variable off if you are short of disk space. Default: "ON"
  • $ExtMemory controls the use of Extended Memory (or XMS). Once deactivated, extended memory cannot be reactivated. Default: "ON" if available
  • $IsoLatin controls the interpretation of upper ASCII codes in included and patched files. The IsoLatin settings are processed at the time the file is loaded, not at the time the file is processed. Default: "ON"
  • $ProgressX and $ProgressY controls the position of the progress window displayed in VESA graphics during archive download and decompression. Default: 200 200
  • $EXT2-Backup controls the update of superblock backups in Linux ext2 filesystem. Superblock backups take a few seconds to do and are never used by current kernels (only by e2fsck).
  • $Security-Gateway controls the gateway-server used for user authentication. Our special authentication gateway must be running on the target computer. Default: "${BOOTP-Server-IP}@89" (ie. the TFTP server, on port 89)
  • $Security-Check contains the answer of the security server for the last check performed, either PASSED or FAILED. Default: "FAILED"
  • $Security-Passwd, $HelpTopic, $OnExit, $OnKey-... are used internally.

See also BOOTP variables and MrZip-specific variables.

MrZip-specific variables

The following variables are only used within MrZip.

  • $TempPath controls the directory where temporary files will be stored. Default: <empty> == current directory
  • $DumpFormat controls the way archives are dumped to the log when requested. It is a string containing
    • "h"/"H" to display the archive header
    • "b"/"B" to summarize/dump boot sectors
    • "s"/"S" to display a short/long allocation summary
    • "d"/"D" to display a short/long directory listing
    • "f"/"F" to summarize/dump files
    Default: "hbD"
  • $FragmentSize controls the size of archive pieces. If you do not use InCom's extended TFTP server, you should set this to "30 MB". Default: "87 MB"
  • $SourceArchive, $DestArchive, $Filter... are used internally.
BOOTP variables

The following BOOTP-... and DHCP-... variables are recognized, as long as a BOOTP/DHCP reply has been received (TCP/IP Bootprom must be reported as detected):

        $BOOTP-Client-ID
        $BOOTP-Your-IP
        $BOOTP-Server-IP
        $BOOTP-Gateway-IP
        $BOOTP-Bootfile
        $BOOTP-Server-Name
        $BOOTP-Subnet-Mask
        $BOOTP-Time-Offset
        $BOOTP-Routers
        $BOOTP-Time-Servers
        $BOOTP-Name-Servers
        $BOOTP-Domain-name-Servers
        $BOOTP-BOOTP-Log-Servers
        $BOOTP-Cookie-Servers
        $BOOTP-Lpr-Servers
        $BOOTP-Impress-Servers
        $BOOTP-Resource-Location-Servers
        $BOOTP-Host-Name
        $BOOTP-Boot-Size
        $BOOTP-Merit-Dump
        $BOOTP-Domain-Name
        $BOOTP-Swap-Servers
        $BOOTP-Root-Path
        $BOOTP-Extensions-Path
        $BOOTP-IP-Forwarding
        $BOOTP-Interface-MTU
        $BOOTP-All-Subnets-Are-Local
        $BOOTP-Broadcast-Address
        $BOOTP-NIS-Domain
        $BOOTP-NIS-Servers
        $BOOTP-NTP-Servers
        $BOOTP-Font-Servers
        $BOOTP-X-Display-Manager
        $DHCP-IP-Address-Lease-Time
        $DHCP-Message-Type
        $DHCP-Server-Identifier
        $DHCP-Message
        $DHCP-Renewal-Time
        $DHCP-Rebinding-Time
        $BOOTP-NIS+-Domain
        $BOOTP-NIS+-Servers
        $BOOTP-Server-Name
        $BOOTP-Bootfile
        $BOOTP-Mobile-IP-Agent
        $BOOTP-SMTP-Servers
        $BOOTP-POP3-Servers
        $BOOTP-NNTP-Servers
        $BOOTP-WWW-Servers
        $BOOTP-Finger-Servers
        $BOOTP-IRC-Servers
        $BOOTP-StreetTalk-Servers
        $BOOTP-STDA-Servers

Other BOOTP/DHCP parameters can be used under the name

        $BOOTP-Option-n
where n is the decimal representation of the BOOTP option number.

Do not mix-up BOOTP-Gateway-IP, which is the gateway to use for TFTP and should be 0.0.0.0 if the TFTP server is in the same subnet, and BOOTP-Routers, which contains the default IP gateway(s). The TCP/IP Bootprom sometimes seems to set the value of BOOTP-Gateway-IP from the value in BOOTP-Routers, causing each TFTP ack packet to be sent to the router first. To avoid such behaviour, if your TFTP server is in the same subnet as the client, force BOOTP-Gateway-IP to 0.0.0.0 (thanks to Maciek Uhlig for having pointed out this problem).

Monitoring commands

This section lists commands for monitoring the system state. Optional arguments are listed between parenthesis (I would have prefered square brackets, but LaTeX do not like them at this place...)

Interact

Show the log and turn to interactive mode until QUIT or EXIT is entered. Type HideLog before quitting if you want to avoid disturbing log messages during batch execution.

Help (topic)

Load the on-line help file (bpbatch.hlp) and display the description of the given topic. If no topic is provided, or if the topic is unknown, display the help index.

Log "text"

Display the string on the log. No return/linefeed is implicitely added.

Echo "text"

Display the string on the log and go to the next line. Equivalent to

        Log "text\r\n".
LogVars ("pattern")

Log (ie. display on the log) all variables matching the given pattern. The pattern can contain wildcards (? and *).

Example: LogVars "BOOTP-*"              list all BootP variables
LogDir "path/pattern"

Log (ie. display on the log) all files from the given path that match the pattern. The pattern can contain wildcards (? and *).

Example: LogDir "/usr/g*p"              list files names like g...p
LogTree "path"

Log the directory tree starting with the given path as root.

LogFile "filename"

Log the content of the file. The file must be no more than 64 KB big.

ShowLog

Make the log visible if it was hidden. Automatically performed when ESC is pressed with "$AutoShowLog" == "ON" and when entering interactive mode.

HideLog

Prevent log messages to appear on the screen. Default state when BpBatch, MrBatch and MrZip are started on a script file.

CaptureLog

Record all log output to a 64 KB buffer until EndCapture is issued. Wrap around buffer if the log output is more than 64 KB big. This command can be used to create a text file with an arbitrary content. The EndCapture MUST occurs within the same batch file.

EndCapture ("filename")

End up the capture of the log. If a filename is given, store the captured text to a file. Otherwise, discard it.

Beep

Make a sound. This command is equivalent to Echo "\007".

Control commands

This section lists commands that control the batch execution. Optional arguments are listed between parenthesis.

Include "filename"

Load the given file and start up the parser on it. Go back to the current point when the include file processing is done. The interpretation of characters above ASCII 127 within the include file depends on the value of $IsoLatin at the time the file is included.

OnExit command

Setup an exit-handler that will automatically be evaluated at the end of current batch file.

Goto label

Move the execution cursor to the given label (ie. the line starting with :label)

Eval "command"

Perform all substitutions on the "command" and run the parser on it.

If ...
  If (not) <expr1> (==|!=|<|>|>=|<=|=>|=<|<>) <expr2> <command>
  If (not) (ci) "str1" (==|!=|<|>|>=|<=|=>|=<|<>) "str2" <command>
  If (not) (ci) "str1" Match-Expr "pattern" <command>
  If (not) (ci) "str1" Match-Passwd "unix-passwd" <command>
  If (not) (ci) "str1" in "wordlist" <command>
  If (not) (ci) "str1" in-file "filename" <command>
  If (not) exist "filename" <command>
  If (not) valid <disk>:<partition> <command>

These commands execute command; if the test succeeds. The 1st form compares two numerical expressions. The 2nd form compares two strings, optionally case-insensitive. The 3rd form tests if "str1" matches the given pattern (wildcards allowed). The 4th form tests if the clear password "str1" matches the Unix-crypted password. The 5th form tests if "str1" is included in the word list. The 6th form tests if "str1" is included in the word file. The 7th form tests if the given file exists. The 8th form tests if the given partition is valid (i.e. formatted). This form is only supported by BpBatch versions after February 1999.

Set ...
  Set variable = "string-value"
  Set variable = <expr>

Setup a value for the given variable. If the given value is a numerical expresison, it will be implicitely converted to a string. A variable can be used anywhere by refering it as $variable or ${variable}. If the resulting reference is to be interpreted as a string, it should be enclosed between double quotes: "$variable" or "${variable}".

Delay duration

Waits until the specified duration (expressed in seconds) expired. See also the paragraph on the format of durations.

GetTime variable, GetDate variable

Get the CMOS time and store it into variablein the form HH:MM:SS. Get the CMOS date and store it into variablein the form YY/MM/DD. This can be used to customize the behavior of your boot scripts depending on the time of day or on the date.

SetTime "HH:MM:SS", SetDate "YY/MM/DD"

Set the computer CMOS time or date to the given value. If you have a security gateway (our special TFTP server) running, you can automatically adjust the CMOS time and date of the client computers at each boot by evaluating the following command:

        include "$Security-Gateway:gettime"
If you want to understand what this command does, just type:
        logfile "$Security-Gateway:gettime"
Poweroff

Turn off the computer. This command only works if the computer is Advanced Power Management (APM) compatible.

Keyboard-related commands

This section lists commands that let you monitor the keyboard input. Optional arguments are listed between parenthesis. See also under National Language Support.

GetKey (variable)

Indefinitely wait until a key is pressed and store it in the variable.

WaitForKey duration (command)

Wait until a key is pressed for no more than duration seconds. If no key has been pressed after the given time, evaluate the command. Otherwise, leave the key in the keyboard buffer. See also the paragraph on the format of durations.

Input (variable (max-length))

Read a return-terminated string from the keyboard and store the result string in variable (without the terminating return). If max-length is given, do not allow the user to enter more than this number of characters.

See also GetPasswd under Security-related commands.

OnKey "c" command

Setup a key handler that will automatically evaluate the given command when the key "c" is pressed (except is explicitely waited by a GetChar or an Input command). If the string "default" is used instead of a single character, the command is executed if any other key is pressed.

Text output commands

This section lists commands used to perform regular text output. All these commands can be used in graphic mode also, with the same behaviour (except that text mode provides 80x25 characters while graphic mode provides 100x37, because graphic mode characters are of size 8x16). Optional arguments are listed between parenthesis. See also under National Language Support.

Print "text"/expr

Print the specified string/expression at current cursor position and using current text attributes, then move the cursor. Add "\r\n" to the end of the string to go to the next line.

TextAttr fg-color bg-color

Setup the text attributes. One can also put a single numeric value representing both colors and defined as 16*bg-color+fg-color.

If you need more fantasy, you can use LoadFont. See under National Language Support.

At line,col (command)

Move the cursor position to the specified position and evaluate the command if provided.

Example: At 10,20 Print "Gnats and rats !"
Clear (color (pattern-char (top,left,bottom,right)))

Fill the given text area with the given pattern-char (either a string or the decimal ascii code). The area defaults to the full screen, the pattern char defaults to the full block (ASCII dec 219) and the color defaults to black (clear screen). Move the cursor to the upper left corner of the cleared area.

BpMenu backward compatibility commands
  .ATT (<attribute>)
  .CLS (<attribute>)
  .DEF <key> (<timeout_val>)
  .KEY <key> <filename>
  .POS ((<x>) <y>)
  .PWD <key> <cpasswd>
  .WLN (<text>)
  .WRT <text>

See InCom's manual for more infos. We wrote some time ago a program program for editing menu files using this syntax, but it is preferable to make your menus using the new explicit syntax. Note that the .PWD command is not implemented because we do not now the password crypting algorithm used by InCom GmbH.

Graphics output commands

This section lists commands used to perform graphic-mode output. For the functions listed in this section, coordinates are given in pixels. You can also use all text output commands (see above) in graphic mode. Optional arguments are listed between parenthesis.

Note that the graphic mode is automatically turned on whenever a graphic command is used, unless the variable VESA is set to "OFF".

InitGraph ("mode")

Turn on VESA graphics. The origin is on the upper-left corner of the screen (0 0). VESA graphics may hang some computers under Windows 95. Run MrBatch with the -v option to avoid such problems.

You can request a specific video mode if you use the parameter "mode" This parameter is optional: if you do not specify any value, the video mode will be taken from the first field of the VESA-Modes variable.

Valid modes are :

  • 640x480 => 640 by 480 pixels, 256 colors
  • 800x600 => 800 by 600 pixels, 256 colors (default mode)
  • 1024x768 => 1024 by 768 pixels, 256 colors
  • 1280x1024 => 1280 by 1024 pixels, 256 colors

The VESA-Modes variable lists the video modes supported by your hardware.

Example: InitGraph "640x480"

CloseGraph

Close VESA graphic mode and go back to text mode.

DrawBar x-pos y-pos width height color

VESA graphics. Draw a filled bar of the given size and colors.

DrawWindow x-pos y-pos width height (bg-color (bar-color)) ("title" (title-color))

VESA graphics. Draw a window of the given size and colors. The background color defaults to LightGray and the title-bar color defaults to Blue. If you include a title string and a color, this text will be displayed in the title bar.

Drawtext x-pos y-pos "text" (fg-color)

VESA graphics. Draw the text string at the given position with a transparent background. The color defaults to text foreground color.

DrawGif "gif-filename" (x-pos y-pos (color-strategy))

VESA graphics. Load the given GIF-87a file and draw it on the screen. The file can be interlaced, but must be in GIF-87a (not GIF-89a). The image size should fit in the selected video mode. You cannot load a 1024x768 GIF file when you selected a 640x480 mode. The GIF position defaults to the top left corner of the screen (0 0).

The color-strategy defines the allocation of colors in the palette when more than 256 colors are needed (for instance when two 256 colors GIF files are displayed simultaneously):

  • Best-Colors use best possible colors for the most recent GIF
  • Spare-Colors try to avoid allocating colors, change existing colors
  • Share-Colors try to avoid allocating colors, use existing colors
  • Reuse-Colors allocate no new color, only use existing colors
The default strategy is Best-Colors.

Security-related commands

This section lists commands that help you authenticate a user. Optional arguments are listed between parenthesis.

Some of these functions cooperate with a Security gateway, that you should first install. See the section on Special TFTP servers for more infos.

GetPasswd (variable (max-length))

Same as Input, but echo stars instead of the typed characters.

Crypt "text" "salt" variable

Apply the Unix crypt function to the given 8-chars text and store the resulting crypted string into variable. The "salt" is usually a two-character string that will be found as the first two characters of the crypted string.

Note that Unix crypt is a one-way function. It is not possible to decode the crypted string. One can only try to crypt another string with the same salt and compre the resulting crypted string.

DESCrypt "text" "key" variable

Crypt the given text using the given 8-chars key and store the result as an hexadecimal string in variable.

DESDecrypt "hexcode" "key" variable

Decrypt the given hexadecimal string using the given 8-chars key and store the result in variable.

MD5 "text" variable

Compute the MD5 checksum of the given text and store it as an hexadecimal string in variable. Can be used as an alternative to the Unix crypt function to check for passwords bigger than 8 characters.

CheckUser "user" "password" "domain"

Connect to the $Security-Gateway and check if the given user exist in the given radius domain and uses the specified password. If the domain is "Unix", use the Unix user/password definition on the security gateway. For any other domain, use the security gateway domain definition file to determine the real Radius or NT domain to check.

Set the value of $Security-Check to "PASSED" or "FAILED". The password do not transit in clear on the network.

Disk-related commands

This section lists commands for preparing the hard-disk. Optional arguments are listed between parenthesis.

GetPartitions variable (disk)

Read the partition table(s) for the given disk and store it as a string into the given variable. The result string is a space-separated list of Type:Size, where

  • Type is FAT16, EXT, BIGDOS, NTFS, FAT32, FAT32-LBA, BIGDOS-LBA, EXT-LBA, LINUX-SWAP, LINUX-EXT2 or the decimal filesystem id for unknown types.
  • Size is the size of the partition in megabytes.
See SetPartitions for more informations about partitions.
SetPartitions "partitions" (disk)

Setup the partition table(s) to the content of the string. The format used is the same that for GetPartitions. This command also reset all boot flags (hint: use SetBootPart).

The main partition table in the master boot record (MBR) has only four entries. Moreover, DOS and Windows accept only ONE FAT partition (called the Primary partition, C:) in the main partition table. Any supplemental FAT partition should be nested in an extended partition (and is thus called a Logical partition). If we give numbers 1-4 to the partitions described in the MBR partition table and numbers 5-8 to the partitions described in the first extended partition, the definition of two FAT partitions would work by defining partition 1 as FAT, partition 2 as EXT and partition 5 as FAT. Partitions 3,4,6,7 and 8 should be marked as UNUSED. The same scheme can be used recursively to define more than two FAT partitions: nesting another extended partition in partition 6 and adding a logical FAT partition in partition 9.

In the most strict interpretation of DOS specifications, that means that entries 3 and 4 of the partition tables are never used. In practice, some versions of DOS and some other OS are able to use more than two partitions per partition table, but there is no clear rule. On this side, BpBatch is rather flexible in its interpretation of partition tables, it can often understands things that OSes cannot.

One universal rule is that there should never be more than one extended partition per partition table, otherwise the partition numbering scheme breaks down.

If you want to try funny configurations, make your own experiments, but don't complain if the OS does not recognize your partitions. The only way it is guarantee to work is to use the primary partition to store the OS boot partition, and to nest all other partitions, one at a time, in extended partitions.

Example of extended partitions :

        SetPartitions "BIGDOS:100 EXT:400 EMPTY EMPTY BIGDOS:400"
GetBootPart variable (disk)

Get the partition number with the boot flag turned on (DOS says: the activated primary partition) and store it to the variable. The first partition is numbered 1. If no partitions has the boot flag turned on, answers zero.

SetBootPart partition (disk)

Set the boot flag to the given partition. The boot flag let the master boot record (MBR) choose which partition to boot on. The first partition is numbered 1.

Blank partition (disk)

Fill the given partitions with zeroes. Can take quite a lot of time for big partitions. Do not format the partition for any operating system. See also Clean.

Clean partitions (disk) ("label")

Fast-format the given partition(s) according to the type declared in the partition table. If a label is given and the filesystem supports it, setup the partition label. For a paranoiac full format, call Blank on the partition first.

Clean is supported for (FAT16) BIGDOS, FAT32, EXT, LINUX-EXT2 and LINUX-SWAP partitions. To clean the master boot record (MBR), use Clean 0.

Clean should be used on data partitions and on MBR/EXT partitions. It is totally useless to clean a partition before unzipping a filesystem on it using FullUnzip.

FullUnzip "full-archive" partition (disk)

Decompress a full disk archive to the given partition, overwriting any existing file (clean-up on the fly).

FullUnzip is supported for (FAT16) BIGDOS, FAT32 and LINUX-EXT2.

This commands turn on VESA graphics to display a progress banner, unless VESA has been turned OFF.

IncrUnzip "incr-archive" "destpath"

Decompress an incremental disk archive to the given path. Files in the archive replace those with the same name on the target path, but other files are not deleted.

IncrUnzip is supported for (FAT16) BIGDOS, FAT32 and LINUX-EXT2. This command is far less efficient than FullUnzip since the existing filesystem structure must be preserved. However, it avoids multiplying the number of different disk images by storing the differences only.

FileUnzip "source-filename" "dest-filename"

Uncompress a file previously compressed with MrZip FileZip command. The file is validated by a 32-bits CRC.

Copy "source-filename" "dest-filename"

Copy the source file to the destinaton file, byte-to-byte. Can be used after a FullUnzip for instance to update configuration files from the server without rebuilding the image. Better to use FileUnzip for big and easy-to-compress files.

Append "src-filename-1" "src-filename-2" "dest-filename"

Copy the first, then the second file to the destination file, byte-to-byte. Can be used on arbitrary large files. The destination file cannot be one of the two source files.

Patch "source-filename" "dest-filename" ("prefix" ("postfix"))

Read the source file and perform variable substitution before writing it to the destination file. The interpretation of characters above ASCII 127 depends on the value of $IsoLatin.

By default, variables are recognized when prefixed by "${" and postfixed by "}". This can be changed to any other non-empty string. remember that if you want to use a dollar sign within the prefix or suffix, you must escape it or it will get macro-evaluated. For instance, if you want to explicitely use the default prefix and postfix, use:

        Patch "source-file" "dest-file" "\${" "}"
MkDir "path"

Recursively create directories from the root to the given full path. If the path already exists, this command has no effect.

Delete "filename", Del "filaname"

Remove the given file. The file must exist.

DelTree "path"

Recursively remove all files and directories under the given path, and remove the directory itself.

Boot commands

This section lists commands for continuing the boot process. Optional arguments are listed between parenthesis.

HideBootProm

Restore the memory and the interrupt vectors allocated by the bootprom. All attempts to make TFTP transfers will fail after calling this command. It is usually a good idea to call this command before HdBoot, or you might run short of memory under DOS/Windows. This command is implicitely called by FloppyBoot.

Note that although this function restore all vectors "officially" rerouted by the BootProm, it does not seems to restore everything. But it works well enough for DOS and Windows.

LoadRamDisk "ramdisk-filename"

Load a floppy disk image into the extended memory and redirect the BIOS Disk Services to make floppy disk calls use this image instead. This command implicitely calls HideBootProm. Call FloppyBoot to boot on the ramdisk you just loaded.

This kind of ramdisk may not be as robust as what you get when you use the TFTPBoot command. The only advantage is that it only steals a few hundred bytes of conventional memory instead of the >64 KB reserved by the TCP/IP BootPROM. Warning, nothing secures the extended memory in which the ramdisk resides. There is no way to uninstall such a ramdisk.

LoadZRamDisk "ramdisk-filename"

Do the same as LoadRamDisk, but for an image that has been compressed using MrZip FileZip command. Compressed ramdisks are protected against data corruption (and uncomplete download) by a byte count and a 32-bits CRC.

TFTPBoot "remote-bootfile"

Chain to another boot file (for instance a floppy image made with InCom's BpShell program). See the file referencing conventions for accessing a file on another TFTP server.

FloppyBoot

Hide the Boot ROM, load the floppy disk boot sector and boot on it.

HdBoot (disk)(:partition)

Load the given boot sector and boot from it. The disk default to zero, the first hard disk, and the partition defaults to zero, ie. the master boot record. You can boot from any partition, but be warned that Windows 95 may not let you boot a partition that has not been set as the boot partition (hint: use SetBootPart).

This command does not implicitely call HideBootProm, so you might want to call it before.

LinuxBoot "kernelfile" ("command-line" ("ramdisk-file"))

Load the given kernel and ramdisk into the high memory, setup the command line and boot the kernel. It is a good idea to put at least a minimal command line with the location of the root filesystem (like "root=dev/hda1"/). If you are using a linux system that heavily relies on lilo (like RedHat Linux 5.1), it may be necessary to add to the command line something like BOOT_IMAGE=linux. Note that the kernel can be loaded by TFTP (automatically cached on the hard disk) or directly from the target root partition.

This command works for small and big kernels (zImage and bzImage).

National language support

This section lists commands related not national language support. Optional arguments are listed between parenthesis.

RemapKeys "original-keys" "remapped-keys"

National keyboard support. Remap given keys to other characters. For instance, to swap the Y and Z keys, use

        Remapkeys "yzYZ" "zyZY"
It is a good idea to use the quoted octal notation when using characters not included in the minimal ASCII character set, in order to avoid a dependency to the iso-latin modal settings.

For international keyboards, there are two keys that produce a backslash in non-remapped (US) mode. Each of them can be independantly remapped, thanks to the fact that BpBatch sees one of them as a key answering ASCII code 252 (octal) or ASCII code 335 (octal) when shifted.

If you send me a sample script that does keyboard mapping for your national keyboard, I will make it available under http://cuiwww.unige.ch/info/pc/remote-boot/soft/sample-scripts To help you make your own keyboard mapping, I suggest pressing all special keys without remapping the keyboard and writing down the character they produce. These will be the original-keys. The remapped-keys simply are the key you would have liked to see, in the same order. If some keys (either original or remapped) produce characters above ASCII dec 127, use the quoted octal notation. You can easily get the octal code for any given character by looking in the ASCII table of HelpPC for instance (HelpPC is a shareware hypertext on-line help program by David Jurgens).

RemapAltkeys "original-keys" "remapped-keys"

National keyboard support. Remap the given keys when ALT is depressed For instance, to map Alt-2 to the ampersand sign, use

        RemapAltKeys "2" "@"
Note that dead keys are not supported.
LoadCodePage "cpxxx.bin"

Load and activate the given binary Codepage file. Codepages are used for the translation of Unicode characters (present on VFAT valumes for instance) into 8-bits characters. If you do not have the right Codepage loaded, you will get FAT warnings while accessing the filesystem when special characters are encountred.

All binary codepage files are available at http://cuiwww.unige.ch/info/pc/remote-boot/soft/codepage.zip

The default codepage is 850, a reordered superset of ISO-Latin-1. If you load a more exotic codepage, you should usually turn the variable $IsoLatin to "off" or you might get meaningless implicit conversions. Moreover, if you want to display exotic characters, you should also load the proper screen font (use "LoadFont").

LoadFont "fontfile"

Load and activate a VGA/VESA font, both in text and graphic mode. The font file must be a binary file of 16 bztes/characters (8x16 bitmap). This command can be used for National Language Support as well as for Fantasy support.

An archive with several fantasy fonts is available at http://cuiwww.unige.ch/info/pc/remote-boot/soft/fonts.zip. This archive also contains a program to extract fonts for your codepage from the DOS .CPI file.

Commands specific to MrZip

Source...
  Source (i)archive "filename"
  Source path "path"

Set the source for the archive manipulation to the given (incremental) archive file or disk path.

Dest...
  Dest (i)archive "filename"
  Dest (i)dump
  Dest path "path"

Set the destination for the archive manipulation to the given (incremental) archive file, dump or disk path. To control the quantity of data displayed during dump, use the $DumpFormat special variable.

FileZip "source-filename" "dest-filename"

Compress a file for further decompression with FileUnzip or for using as ZRamDisk. The file is validated by a 32-bits CRC.

Filter...
  Filter -"pattern"
  Filter +"pattern"

Avoid/allow files and directories matching the given pattern (wildcards allowed) to be included in the archive. The pattern is matched agains the full pathname. By default, all files are included in the image. You only need to explicitely allow files that where cancelled by a filter. Each negative filter has its own positive filter (allowed) sublist.

For DOS/Windows images, you will typically use

        Filter -"*.swp"
        Filter -"temp/*"
and for Unix images, you will typically use
        Filter -"var/log/*"
        Filter -"tmp/*"
CopyArchive

Start the archive manipulation operation, according to source, destination and filter settings. Except in a few circumstances, you will probably use the shortcut below instead of explicitely calling CopyArchive. One circumstance in which you will use CopyArchive explicitely is when you want to change the fragmentation of an image, as follow:

        set FragmentSize="30 MB"
        Source archive "original.imz"
        Dest archive "refragmented.imz"
        CopyArchive
FullZip "path" "full-archive"

Shortcut for

                Source path "path"
                Dest archive "full-archive"
                CopyArchive
You should usually first setup filters.
IncrZip "path" "incr-archive"

Shortcut for

                Source path "path"
                Dest iarchive "incr-archive"
                CopyArchive
FullDump "full-archive"

Shortcut for

                Source archive "full-archive"
                Dest dump
                CopyArchive
IncrDump "incr-archive"

Shortcut for

                Source iarchive "incr-archive"
                Dest dump
                CopyArchive
XCopy "srcpath" "dstpath"

Shortcut for

                Source path "srcpath"
                Dest path "dstpath"
                CopyArchive

5.2 NoBreak.sys

Nobreak.sys is a very small (about 350 bytes only) driver that you include at the beginning of your config.sys. Its goal is to secure the boot process, until the user is logged in. DOS provides a setting for this (namely BREAK=OFF), but it is not drastic enough, and has almost no effect in the autoexec.bat. Our driver works by modifying the scan-code of the key pressed when a break is requested, directly at the BIOS level. This way, no program at all can receive a break until break is enabled again.

The driver must be loaded from the config.sys (or using the devlod program from Undocumented DOS). Afterwards, break can be enabled by sending Yes to the NOBRK pseudo-device, and disabled again by sending No (in fact, only the first character, Y or N is significant).

As this driver relies on the BIOS, it does only work for DOS and Windows 3.1. Windows 95 has its own low-level keyboard handling routines.

Assembler source code is available.


Next Previous Contents