Phindows uses data compression to compress the data that is sent from host computer
to QNX target.
You can use the
Phindows Connect dialog to specify one of these data-compression options:
- Byte-Pair Encoding (BPE)
- Performs the best data compression and is recommended for all serial
connections. Although BPE is inexpensive to decode (both in memory and CPU
usage), it does require a fair amount of CPU on the host QNX machine. When link
speeds are low (such as with modem links), the extra cost in CPU on the sending
side is well worth the tradeoff.
- Run Length Limited (RLL)
- Provides good data compression. Although not as highly compressed as BPE, RLL
encoding is both quick to decode and encode. We recommend RLL encoding for
network TCP/IP connections because it places less CPU load on the QNX host, yet
provides fair compression.
- Gzip Image Compression
- Provides excellent compression using a modified Lempel-Ziv algorithm (LZW). You
can enable Gzip image compressoin by selecting Gzip Image
Compression on the Connect dialog.
- None
- With data compression turned off, Photon draw events are transmitted as-is. This
might make sense if the connection bandwidth is VERY high (say 100Mb Ethernet),
making the extra processing time involved in data compression an unnecessary
step.