Command: RDISK.COM

  RDISK is a RAM-disk driver like TDSK (Turbodisk) and SRDISK. It creates
  a "fast" disk using up to 2 GiB of XMS memory. Files can be uploaded
  via AUTOEXEC to the RAM-disk and accessed at memory speeds. RDISK is
  a simple RAMdisk driver with no resizing or other options.

Syntax:

  DEVICE[HIGH]=rdisk.com [/F] [/G][/Snn] [/:L]

Options:

  RDISK requires only a /S size and a /: drive-letter switch. All RDISK
  switches are:
  /F    For RDISK, UHDD, and UDVD2, makes "free" any reserved XMS set
        by XMGR for a DOS "game". /F should be issued only from
        the LAST of these drivers to load, so any XMS reserved for
        a DOS "game" will STAY reserved until /F "frees" it!
        (new version only!)
  /G    For RDISK, UHDD, or UDVD2, reserves ALL "leftover" XMS memory
        with old DOS games that FAIL if the game finds unused XMS!
        /G should be issued only from the LAST of these drivers to
        load, as NO free XMS will be left afterward! (new version only!)
  /Snn  Specifies a desired RAM-disk size in megabytes of XMS memory.
        Values are any number from 2 to 2047 (2 Gigabytes). When
        /S is omitted or invalid, a 25-Megabyte default is used.
  /:L   Specifies the DOS drive letter desired to access RDISK files.
        L may be any available drive letter from A to Z, e.g. /:N
        assigns drive N: to all RDISK files. If the drive letter
        is too high or already in use, RDISK aborts, and users may
        need "LASTDRIVE=" in CONFIG.SYS / FDCONFIG.SYS to set more
        drives. When RDISK loads from CONFIG.SYS, or if /: is omitted,
        the next free drive letter is used.

Comments:

  RDISK is a DOS RAM-disk driver. It creates a fast disk drive from up
  to 2 GIGABYTES of XMS memory! AUTOEXEC.BAT / FDAUTO.BAT can copy
  critical programs or files to the RAM-disk, where DOS can access them
  at memory speeds. RDISK is a very small driver, for users who do not
  need resizing nor other features.
  For all switches in each driver, a dash may replace the slash and lower
  case letters may be used if desired.
  RDISK and RDISKON are Closed Source DOS drivers for PCs with an 80386+
  CPU (UHDD requires an 80486+ CPU) and using MS-DOS V5.0+ or a
  fully compatible variant (new version only!) Older versions maybe
  Open Source.
  For more information read "README.txt" in drivers.zip.

Examples:

  Comment: There are new closed source drivers for UHDD.SYS (=XHDD.SYS)
  and UVD2.SYS (=XDVD2.SYS) which may have other options. So please do
  not rely on the options in the examples!
  A) A small real-mode system that needs only XMS may use this
    CONFIG.SYS/FDCONFIG.SYS example file:
       ..
       ..
     DOS=HIGH
     DEVICE=C:\BIN\XMGR.SYS /Rnn              ;R if DOS "games" need it
       ..
       ..  Int 13h drivers cached by UHDD load now.
       ..
     DEVICE=C:\BIN\UHDD.SYS /S20 /H /O        ;Min. 20 MB recommended
     DEVICE=C:\BIN\UDVD2.SYS /D:BLURAY1 /H    ;Must load after UHDD
     DEVICE=C:\BIN\RDISK.COM /S5 /F           ;Optional. If not used,
                                              ; UHDD/UDVD2 can issue /F
       ..
       ..  Further CONFIG.SYS commands can be given here.
       ..
  B) Real-mode systems with V3.70+ UMBPCI and XMGR do not need the LOWDMA
     driver, as XMGR has an "I-O Catcher" for UMBPCI. This scheme takes
     NO low memory if /W can be used (MS-DOS etc.) or only 544 low memory
     bytes without /W (PC-DOS etc.). XMGR and other drivers load direct
     to UMBPCI "Shadow RAM"! Systems which permit multiple providers of
     upper memory (MS-DOS, PC-DOS, etc.) can also load an "EMM" driver as
     shown below, to map the B000-B7FFh "Monochrome Graphics" area as 32K
     more upper memory. For more SERIOUS protected-mode notes, please
     READ Section 6 below! An example CONFIG.SYS file is:
       ..
       ..
     DOS=HIGH,UMB
     DEVICE=C:\BIN\UMBPCI.SYS
     DEVICE=C:\BIN\XMGR.SYS /W /Rnn            ;W only when permitted!
                                               ;R <= 15.5 MB with JEMM!
     DEVICE=C:\BIN\JEMM386.EXE I=B000-B7FF X=C800-EFFF ...   ;Optional
       ..
       ..  Int 13h drivers cached via UHDD load now
       ..  and can be loaded in UMBPCI upper memory.
       ..
     DEVICEHIGH=C:\BIN\UHDD.SYS /S200 /H /O    ;Fast 200 MB cache
     DEVICEHIGH=C:\BIN\UDVD2.SYS /D:CDROM1 /H  ;Must load after UHDD
     DEVICEHIGH=C:\BIN\RDISK.COM /S50 /F       ;Optional. If unused,
                                               ; UHDD/UDVD2 can issue /F
       ..
       ..  Further CONFIG.SYS commands can be given here.
       ..
  C) A protected-mode system with XMGR and an "EMM" driver can use XMGR's
     "boot", taking a minimum 304 bytes of low memory for a 24-entry "XMS
     Handles" table, plus any low memory the "EMM" driver may need. For
     more SERIOUS protected-mode notes, please READ Section 6 below! A
     CONFIG.SYS example file is:
       ..
       ..
     DOS=HIGH,UMB
     DEVICE=C:\BIN\XMGR.SYS /B /N24 /R15.5     ;24 Handle XMGR "boot"
                                               ;R <= 15.5 MB with JEMM!
     DEVICE=C:\BIN\JEMM386.EXE I=B000-B7FF ...
     DEVICEHIGH=C:\BIN\XMGR.SYS                ;Loads the runtime XMGR
       ..
       ..  Int 13h drivers cached by UHDD load
       ..  now and can load into upper memory.
       ..
     DEVICEHIGH=C:\BIN\UHDD.SYS /S400 /H /O /P ;Optimal 400 MB cache
     DEVICEHIGH=C:\BIN\UDVD2.SYS /D:MYDVD /H   ;Must load after UHDD
     DEVICEHIGH=C:\BIN\RDISK.COM /S125 /F      ;Optional. If unused,
                                               ; UHDD/UDVD2 can issue /F
       ..
       ..  Further CONFIG.SYS commands can be given here.
       ..
  In each example above, UDVD2 must load after UHDD, so UDVD2 will "find"
  UHDD in memory and call it for CD/DVD file caching.

  Users that need RDISK with a specific drive letter may delay loading
  it until AUTOEXEC.BAT / FDAUTO.BAT is run. If /F or /G are also needed
  for DOS games, RDISK must issue them from AUTOEXEC, since it is then
  the last of these drivers to load. Whenever RDISK is used, AUTOEXEC.BAT
  must also issue commands to copy all RDISK programs and data up to the
  RAM-disk, as XMS memory is LOST when PCs shut down! Such copies
  require little time.
  If UHDD and RDISK will both run, users must balance how much XMS memory
  the drivers take. UHDD can set a 400-MB cache, as in example C above,
  and RDISK can request 125-MB of XMS for its programs, "fast" data files
  and compiler TEMP files. Such sizes should be optimal on most systems
  but can be adjusted up or down, as desired. All remaining XMS memory
  is left free for use by other programs. The basic "plan" is for RDISK
  to hold programs and high-speed files, while UHDD then caches "regular"
  data files. Properly balanced use of XMS memory will give a VERY fast
  DOS system!

Command: RDISK.COM

Syntax:

Options:

Comments:

Examples:

See also: