FreeDOS help system (hhstndrd 1.0.8 en)[rdisk]

Command: rdisk

RDISK is a DOS RAM-disk driver like tdsk (Turbodisk).


rdisk [/Sn] [/:L]


/Sn Specifies a desired RAM-disk size in megabytes of XMS memory. Values may be any number from 2 to 2047. /S1024 or more creates a 1- to 2-GIGABYTE RAM-disk! If /S is omitted or invalid, a 25-MB RAM-disk is created by default. For old V2.0 XMS managers (ROM-DOS etc.) only /S2 through /S60 may be 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 will abort, and users may need "LASTDRIVE=" in CONFIG.SYS to set up more drives. If RDISK is loaded by CONFIG.SYS, or if /: is omitted, the next free drive letter will be used.


RDISK creates a "fast" disk drive using 2 Megabytes to 2 GIGABYTES of XMS memory! It loads as a system driver in CONFIG.SYS, or it can load later in AUTOEXEC.BAT or by user command. DOS can copy critical programs, data files, and other directories which need fast access (compiler TEMP files, databases, etc.) to the RAMdisk, where they can be read and written at memory speeds! If loaded after CONFIG.SYS, RDISK files can be assigned to any free DOS drive letter by using its /: switch. RDISK runs with V2.0 or V3.0 XMS managers (60-MB maximum with V2.0 XMS). It uses only 656 to 752 bytes of upper-memory depending on the system configuration, and it can also load in 640K DOS memory. RDISK is a small "load it and forget about it" driver for use when resizing or other features are not needed. For more information read "README.txt" in


IN CONFIG.SYS / FDCONFIG.SYS: An example CONFIG.SYS file using V3.70+ UMBPCI and XMGR is as follows: SHELL=C:\DOS\COMMAND.COM C:\DOS /E:512 /P DEVICE=C:\BIN\UMBPCI.SYS DEVICE=C:\BIN\XMGR.SYS /W DOS=HIGH,UMB DEVICE=C:\BIN\JEMM386.EXE I=B000-B7FF X=C800-EFFF NOEMS ;Optional DEVICEHIGH=C:\BIN\UIDE.SYS /S500 /D:CDROM1 ;Or UIDEJR DEVICEHIGH=C:\BIN\RDISK.COM /S250 ;Optional .. .. Etc. .. An example for AUTOEXEC.BAT: LH C:\BIN\RDISK.COM /S500 /:Q [Load RDISK, assign drive Q:] ... ... ... MD Q:\DOS [Create RAM-disk directories] MD Q:\USERPROG MD Q:\ ... COPY C:DOS\*.* Q:\DOS [Copy DOS files to RAM-disk] COPY C:\USERPROG\*.* Q:\USERPROG [Copy programs to RAM-disk] COPY C:\...\*.* Q:\... [Copy other files, as needed] ... ... [Optional: Verify RAM files] ... PATH Q:\DOS;Q:\USERPROG;Q:\... [Tell DOS "new directories!"]

See also:

autoexec.bat config.sys fdconfig.sys (fdxms (XMS)) (fdxms286 (XMS)) (himem (XMS)) himemx (XMS) jemmex (EMS) lastdrive tdsk ------------------------------------------------------------------------------ Copyright (C) 2010 Jack Ellis, updated 2011 by W. Spiegl. This file is derived from the FreeDOS Spec Command HOWTO. See the file H2Cpying for copying conditions.