Copyright © 2005 SuperSpeed Software, Inc.

All Rights Reserved.


17 August 2005









1.0 Features

2.0 Functionality

3.0 Device Management

4.0 Known Issues

5.0 Version History


1.0 Features


RamDisk Plus Server Edition (v8.0) features:


RamDisk Server Edition (v8.0) features:



2.0 Functionality


The core functionalities of RamDisk Plus and RamDisk are implemented in the drivers "SscRdBus.sys” and "SscRdFdo.sys”, which are located in the "%WinDir%\System32\Drivers” folder. The first driver is responsible for driving a virtual bus device and its physical device objects, and the second for the functional device objects presented to the operating system as disk devices. The drivers have successfully passed the tests required to be signed by Microsoft, and earned them the "Designed for Windows Server 2003" logo.


Each RAM disk has associated with it an image file. In the case of the RamDisk product, the image file contains only the information necessary to describe an empty file system, along with an optional temp folder.


In the case of the RamDisk Plus product, the image file may contain an empty file system or files or programs, as desired. RamDisk Plus supports saving the contents of the RAM disk dynamically (at any time, but with no open handles to the RAM disk), and/or automatically at system shutdown. Additionally, the image file may be moved from one volume to another without destroying the RAM disk. Also, the image file can be expanded to reserve all the required space that would be necessary if the RAM disk was completely full.


Both RamDisk and RamDisk Plus create and load their RAM disk images very early in system startup. This means that, when the system is started, services and programs that start automatically can depend on the RAM disks already being present beforehand. It also means that network resource mappings of RAM disks and RAM disk mount points will be preserved between system start-ups.


RamDisk Plus also features system page file support. Placing the page file on a RAM disk eliminates the wait times associated with paging memory to and from a physical disk.


Almost all the memory resources allocated to the RAM disks are taken from physical memory. This effectively eliminates any burden on the operating system's limited paged and non-paged pools. Nonetheless, care should be exercised to avoid starving the operating system, services and applications of physical memory. Under severe conditions, memory resource starvation may lead to a system crash. Additionally, although physical memory may be available for a RAM disk, over-allocation of the physical memory pool to a disk will adversely affect the performance of other system components reducing overall system performance despite the larger cache sizes.


RamDisk and RamDisk Plus support a single RAM Disk cluster resource. This feature is available on Windows 2000 Advanced Server, Windows 2000 Datacenter Server, Windows Server 2003 Enterprise and Windows Server 2003 Datacenter editions with Cluster Service installed. The products provide cluster-wide access to a RAM disk by mounting it on a user-specified folder in a shared cluster disk. When the RAM disk cluster resource is on-line, all I/O targeted at that shared cluster disk's folder actually occur on the cluster node's local RAM disk, greatly accelerating I/O throughput on the node.


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3.0 Device Management


RAM disk devices may be managed via a graphical user interface (GUI) or a command-line interface (CLI). There are two paths to access the GUI device management tool, one through Control Panel, and the other through Windows Explorer. In Control Panel's classic view, select "RAM Disk Devices". In Control Panel's new view, open "Performance and Maintenance" and select "RAM Disk Devices". In Windows Explorer, right-click on "My Computer" and select "RAM Disk Devices". The GUI is implemented by the file "SscRdCpa.cpl", located in the "%WinDir%\System32" folder.


The command-line utility, "RdCfg.exe”, is located in the "%WinDir%\System32” folder. The tool's usage is displayed by simply typing its name in a command prompt window.

4.0 Known Issues


Windows 2000 Remote Management


In Windows 2000, remote Terminal Server sessions do not maintain fully dynamic namespaces. In particular, when a new disk device is added to the system, a currently established remote session will not 'see' the new device. This behavior does not occur when a device is removed from the system.


To access a RAM disk added to a Windows 2000 machine during a remote session, the user must terminate the remote session and then reestablish a new one. To do this, simply log off, then log back on. The new device will then be visible to processes running in the remote session.


5.0 Version History


SscRdBus.sys – Virtual bus device driver


SscRdFdo.sys – RAM disk device driver


SscRdCpa.cpl – Control Panel (GUI) RAM disk device management tool


RdCfg.exe – Command-line RAM disk device management tool


SscRdSC.dll – RAM Disk cluster resource DLL


SscRdSCX.dll – RAM Disk cluster resource extension DLL