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.

Syntax:

  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).

Options:

  /D  Driver: This option is used to specify the name of the device
      driver. It can also indicate which unit(s) should be assigned and
      to what letter.
      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. You can only use a drive letter which
      is smaller or even with the letter in LASTDRIVE / LASTDRIVEHIGH.
  /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
      assigned). You can only use a drive letter which is smaller or
      even with the letter in LASTDRIVE / LASTDRIVEHIGH.
  /C  Uses conventional instead of high memory.
  /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
      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). You do not have these
        problems when using the program DOSLFN.
  /R  Removes Read-only attribute.
  /I  Install anyway even if another redirector is present.
  /U  Unloads the shsucdx driver from memory.
  /Q  Quiet. Prevents display of the sign-on banner (copyright notice).

Comments:

  SHSUCDX has the following EXITCODES (ERRORLEVEL):
       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

Examples:

  IN CONFIG.SYS / FDCONFIG.SYS:
    DEVICE=XCDROM.SYS /D:SHSU001
  IN AUTOEXEC.BAT:
    SHSUCDX /D:SHSU001

  Example with several CD-ROM drives:
  In CONFIG.SYS /FDCONFIG.SYS:

    MENU 1.    FreeDOS
    MENU 2.    FreeDOS  + IDE CD-ROM (XDROM)
    MENU 3.    FreeDOS  + USB CD-ROM (NOVAC)
    MENU 4.    FreeDOS  + ASPI CD-ROM  (SCSI AIC-75XX 78XX)
    MENU 5.    FreeDOS  + IDE CD-ROM + USB CD-ROM + ASPI CD-ROM
    lastdrivehigh=U
    25?DEVICEHIGH=\fdos\bin\xcdrom.sys /D:IDE-CD
    35?DEVICEHIGH=\fdos\drivers\usb\usbaspi.sys
    35?DEVICEHIGH=\fdos\drivers\usb\usbcd.sys /D:USB-CD
    45?DEVICEHIGH=\fdos\drivers\aspi\aspi8dos.sys
    45?DEVICEHIGH=\drivers\scsi\aspicd.sys /D:ASPICD

  In AUTOEXEC.BAT:
    SHSUCDX /D:IDE-CD,R /D:*ASPICD,S /D:?USB-CD,U /L:0

See also:

 (atapicdd.sys)
  autoexec.bat
  config.sys
  doslfn
  fdconfig.sys
 (gcdrom.sys)
  lastdrive
  lastdrivehigh
 (mscdex)
 (udvd.sys)
  uide.sys
 (xcdrom.sys)

  Copyright © 2003-2004 Robert Platt, updated 2011 and 2020 by W. Spiegl.

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