Command: shsucdx

  SHSUCDX is an unloadable CD-ROM redirector substitute for MSCDEX.
  It supports up to 10 drives. Each drive is single-sector buffered and
  the last 10 directory entries are cached. Each unit from each driver
  can be assigned a specific drive letter.


  shsucdx /D[:][?|*]driver[,[letter][,[unit][,[max]]]] [switches]
    DRIVER  Is the name of the device driver installed to control
            the CD-ROM drive. Prefixing the driver with '?' will
            silently ignore it if it does not exist (or is not actually
            a CD-ROM); prefixing with '*' will also ignore it, but a
            drive will be reserved (see below).
    LETTER  Is the first drive letter to assign to the units on
            this driver. The  default is the first available letter.
            Note: the drive letters assigned to subsequent units will
            always be higher than those assigned to previous units.
    UNIT    Is the first unit on this driver to be assigned a drive.
            Unit 0 is the default.
    MAX     Is the maximum number of units on this driver to be
            assigned drives. The default is all units (or all remaining
            units, if UNIT is given).
    Once installed, /D by itself will display the assigned drives and
    return the number of drives assigned.


  /D  Drive manipulation
      At install time, /D can also be used to reserve space for
      additional drives. Use a single digit to indicate how many
      drives should be reserved (eg: /D1). (If you should happen
      to have a device driver name with a single digit, use the '?'
      prefix.) After installation, the same option will remove the
      drive(s) that were last assigned. It is possible to specify both
      forms of /D, in which case the current drive(s) will be removed,
      then the new drive(s) added.
  /L  Letter:
      This option is an alternative to the LETTER component of /D,
      which it must follow (ie: /D:driver /L:letter). It can also be
      used to return the number of drives installed (/L:0, will return
      255 if not installed) and the letter of each assigned drive
      (/L:1, /L:2, etc., with A: = 1 and 255 if the drive is not
  /C  Memory usage:
      By default, SHSUCDX will load itself into high memory, if
      available, or into low memory if it is already high.  This option
      will prevent that. To be exact:
        SHSUCDX        relocate high
        SHSUCDX /C     stay low
        LH SHSUCDX     relocate low
        LH SHSUCDX /C  stay high
  /V  Memory statistics:
      When this option is used at installation, a summary of memory
      usage will be displayed. This summary includes:
        Static   Code and variables
        Dynamic  Data for each drive and paragraph rounding
        Total    Overall memory usage
  /V  Information:
      When used with /?, or after installation, this option displays the
      compile- and run-time options of SHSUCDX. This information includes:
        8086/386      The minimum processor required
        CD root form  TRUENAME will return \\D.\A.\ instead of D:\
        High Sierra   The original format for the CD file system
        Joliet        The Windows format for long names
        Image on CD   Enables access to an image which is itself on a CD
  /˜   Tilde usage:
      The ISO standard allows for CDs to have names up to 31
      characters and Joliet can have names up to 64 characters. When
      this is reduced to 8.3 for DOS it may lead to duplicated entries.
      This option will remove the duplication by appending a tilded
      number after the name (similar to what Windows does). By default,
      tildes are off.
      This option is also available after installation. By itself it
      will toggle the status (ie. if tildes are currently on, /˜ will
      turn them off and vice versa). Tildes can be explicitly turned
      on or off by adding a '+' or '-' sign (ie: /˜+ will turn tildes
      on, irrespective of the current state).
  /R  Read-only attribute usage:
      By default, files on the CD are given the read-only attribute.
      Should you wish to remove this attribute, this option will do so.
      As with /˜, it can be used after installation and it accepts '+'
      and '-'.
  /I  Install:
      Normally SHSUCDX will refuse to install if it detects another
      redirector (such as MSCDEX). This option will cause SHSUCDX
      to install anyway.
  /U  Unload:
      Unhook the interrupt, free the memory and mark the drive(s) as
  /Q  Quiet:
      Prevent display of the sign-on banner (the copyright notice).
      /Q+ will only display the drive assignments (when used after
      install '-' will indicate a removed drive and '+' an added drive).
      /QQ will display nothing at all.


  This version of SHSUCDX will only work with DOSLFN 0.40a or later.
  Attempting to use an earlier version of DOSLFN may render the entire
  CD or some files inaccessible.
       0  Uninstalled, help, option set
    1-32  Drive number of first installed drive (A=1)
     246  Invalid or unknown option
     247  Unable to uninstall
     248  Not enough memory
     249  No drives assigned (ie. not installed)
     250  No drive letters available
     251  Unit on driver does not exist
     252  Invalid or non-existant driver
     253  Already installed
     254  Unsupported version of DOS
     255  386 required


  Example 1:
    device=c:\FREEDOS\BIN\udvd2.sys /d:CDROM01

  Example 2 with several CD-ROM drives:
    MENU 1.    FreeDOS
    MENU 2.    FreeDOS  + IDE DVD (UDVD2)
    MENU 3.    FreeDOS  + USB CD-ROM (NOVAC)
    MENU 4.    FreeDOS  + ASPI CD-ROM  (SCSI AIC-75XX 78XX)
    25?DEVICEHIGH=\freedos\bin\udvd2.sys /D:UDVD002
    35?DEVICEHIGH=\freedos\drivers\usb\usbcd.sys /D:USB-CD
    45?DEVICEHIGH=\drivers\scsi\aspicd.sys /D:ASPICD

  Assign drive F to the UDVD002 driver, or abort if it is not loaded.
  If the USB-CD driver is loaded, assign it to drive U; else do
  nothing. If the ASPICD driver is loaded, assign it to drive W; else
  reserve space for it, so it can be loaded later. SHSUCDX will return
  the number of drives assigned (or 252 if aborted).

  Example 3:
  SHSUCDX finds the first available drive letter and assigns it to
  device unit 0 of the driver SHSU-CDH. If there is a second and/or
  third CD drive they are assigned to the next available letters in
  Drive letters in use are skipped. The first CD supported by a driver
  is device unit 0 regardless of its SCSI address.

  Example 4:
    SHSUCDX /L:0
  If SHSUCDX is not installed, it will return   errorlevel 255;
  otherwise the number of assigned drives (which can be 0). In either
  case, nothing is displayed.

  Example 5:
    SHSUCDX /D:CD001,,1,1 /D:CD001,,4,1
  SHSUCDX assigns the first available drive letter to device unit 1 of
  the driver CD001 and the next letter to unit 4. This allows access to
  non-contiguous drive units without having to support un-needed units.

  For more examples see UDVD2.SYS.

See also:


  Copyright © 2006-2020 Jason Hood, updated 2022 by W. Spiegl.

  This file is derived from the FreeDOS Spec Command HOWTO.
  See the file H2Cpying for copying conditions.