ClearCube I/Port Quick Reference Guide - Manual (Page 30)

26 • I/Port Installation ClearCube I/Port User’s Guide, Rev. C
General Recommendations for I/Ports
The following recommendations should be observed for best I/Port performance.
RDP-Based I/Ports
As previously noted, RDP is a limited-bandwidth connection when compared to
100baseT Ethernet. In addition, Ethernet bandwidth can be constrained by network
activity anywhere between each end of a connection.
I/O-intensive applications between the PC blade and the I/Port can significantly affect
performance. ClearCube offers these recommendations:
• Do not use I/Ports for writing to CDs or DVDs. Mass-storage devices such as
CD burners and DVD burners rely on a predictable and relatively constant data
transfer rate from the source to the burner. Although modern burners have large
write buffers, the likelihood of a buffer underrun is high, and increases both with
recording speed and with file size. If the user must write files from a blade to CD
or DVD, use the USB 2.0 connector on the front of the PC blade.
• Do not use I/Ports to transfer extremely large files. Although the I/Port
provides robust file transfer capabilities, the limited bandwidth inherent in RDP
can cause these file transfers take an exceedingly long time. If the user must write
extremely large files to a blade or to the network, use the USB 2.0 connector on
the front of the PC blade.
• Do not write large files directly to I/Ports. The RAM disk on the XPe I/Port is
limited to 16 MB, and is reserved as a temporary space for updating software on
the I/Port. Attempts to write a file larger than 16 MB to the RAM disk will fail.
Attempts to write a series of files with a sum file size greater than 16 MB will
eventually fail when the 16 MB limit is exceeded.
Individual files with a file size greater than 56 MB cannot be written through the
I/Port to an attached USB peripheral storage device. This is by design, and
represents a security feature that limits moving large files such as software.
Folders containing multiple files, with a total size greater than 56 MB can be
written through, as long as the 56 MB limit is not exceeded.
The Flash disk in the I/Port is write-protected by the Enhanced Write Filter. Writes to
the C:\ drive, including temporary files, are written to an area in RAM that is separate
from the RAM disk and is shared by the operating system. When the sum of the files
and the operating system’s RAM requirement exceeds the total amount of available
RAM, the I/Port will suffer a system error. This can be cleared by rebooting the I/Port.
However, data in RAM cannot be recovered.
• For normal usage, leave the Write Filter turned on. This prevents persistent
writes to the Flash disk and helps keep the device secure. Since applications are
actually run on the PC blade in an I/Port environment, there is no need for the
user to write data to the local I/Port.
• Upstream audio is not supported by RDP. Microphones can only be used as
local devices on the I/Port, and not as I/O devices to send content to the blade.
This is a limitation of RDP.
• Lengthy RDP sessions may result in slower throughput. If the connection
through RDP appears to have slowed down significantly, close the RDP session
and restart the I/Port.