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 ramdrive.sys(CMD)               19 June 1992               ramdrive.sys(CMD)


 Name

    ramdrive.sys - create a RAM disk

 Syntax


    device=[drive:][path]ramdrive.sys [DiskSize SectorSize] [/e|/a]

    device=[drive:][path]ramdrive.sys [DiskSize SectorSize NumEntries]
    [/e|/a]


 Description

    Creates a RAM disk in your system's random-access memory (RAM) to simu-
    late a hard disk drive.  RAM disks are much faster than hard disk disks
    because the information they contain is always loaded into memory. RAM
    disks are temporary-any data you place on a RAM disk is lost when you
    turn off your computer.  You can set up as many RAM disks as you want,
    limited only by the amount of memory your computer has. To do this, add
    one RAMDRIVE.SYS line to your CONFIG.SYS file for each additional RAM
    disk.

 Parameters


    [drive:][path]
                  Specifies the location of the RAMDRIVE.SYS file.

    DiskSize      Specifies the size (in kilobytes) of the RAM disk.  Valid
                  values for DiskSize are in the range 16 through 4096.  The
                  default value is 64.

    SectorSize    Specifies the disk sector size (in bytes).  Valid values
                  for SectorSize are 128, 256, and 512.  The default value is
                  512.  If you include a value for the SectorSize parameter,
                  you must also include a value for the DiskSize parameter.
                  Although you can change the SectorSize value, the default
                  value is strongly recommended.

    NumEntries    Specifies the number of files and directories you can cre-
                  ate in the RAM disk's root directory.  Valid values for
                  NumEntries are in the range 2 through 1024.  The default
                  value is 64.  If you include a value for the NumEntries
                  parameter, you must also include values for the DiskSize
                  and SectorSize parameters.


 Switches


              /e  Creates the RAM disk in extended memory instead of in
                  expanded or conventional memory.

              /a  Creates the RAM disk in expanded memory instead of in
                  extended or conventional memory.


 Notes


    Using the NumEntries parameter

    RAMDRIVE.SYS rounds the number you specify up to the nearest sector
    boundary.  If there is not enough memory to create the RAM disk as speci-
    fied, RAMDRIVE.SYS attempts to create it with a limit of 16 directory
    entries.  This can result in a RAM disk with a different limit from the
    one you specified.

    Using conventional memory

    Although specifying a memory type is optional, it is strongly recom-
    mended. If you omit both the /e and /a switches, RAMDRIVE.SYS uses your
    system's conventional memory.  It is not a good idea to use conventional
    memory for a RAM disk, because this reduces available work space for pro-
    grams.  However, if you do not have extended memory, expanded memory, or
    a hard disk drive, you might want to use conventional memory for a RAM
    disk.  A RAM disk can increase the speed of a floppy disk system signifi-
    cantly enough that it may be worth the loss of some conventional memory.

    Using extended memory

    If your system has extended memory installed (starting at the 1-megabyte
    boundary), you can use this extended memory for one or more RAM disks.
    For RAMDRIVE.SYS to use extended memory, you must first install HIMEM.SYS
    or another extended-memory manager that conforms to the
    Lotus/Intel/Microsoft/AST eXtended Memory Specification (XMS).  In your
    CONFIG.SYS file, the device command that installs the XMS extended-memory
    manager must precede the commands that install the RAM disk.

    Using expanded memory

    For RAMDRIVE.SYS to use expanded memory, you must configure your system
    so that it provides expanded memory.  In your CONFIG.SYS file, the device
    command that installs the expanded-memory manager (such as EMM386.EXE)
    must precede the device command that installs RAMDRIVE.SYS.  The
    expanded-memory manager must conform to the Lotus/Intel/Microsoft
    Expanded Memory Specification (LIM EMS).

    Increasing the efficiency of a RAM disk

    For the best results with a RAM disk, you can define a TEMP environment
    variable and set it to point to a subdirectory on the RAM disk.

 Examples

    To create a RAM disk in extended memory and allocate 64K (the default
    amount) of extended memory to RAMDRIVE.SYS, add the following line to
    your CONFIG.SYS file:

       device=ramdrive.sys /e


    Since no location is specified, MS-DOS searches for RAMDRIVE.SYS in the
    root directory of your startup drive.

    Suppose you want to install RAMDRIVE.SYS in expanded memory and allocate
    4 MB (4096K) of expanded memory to the RAM disk.  To do this and to
    specify that RAMDRIVE.SYS is located in the DOS directory on drive C, add
    the following line to your CONFIG.SYS file:

       device=c:\dos\ramdrive.sys 4096 /a


    Now suppose you want to allocate 1024K of extended memory to RAMDRIVE.SYS
    and create a RAM disk that has 512-byte sectors and a limit of 1024
    entries in its root directory.  To do this and to specify that
    RAMDRIVE.SYS is located in the DEVICES directory on drive D, add the fol-
    lowing line to your CONFIG.SYS file:

       device=d:\devices\ramdrive.sys 1024 512 1024 /e