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Showing posts from September, 2011

Linux rfcomm serial communication

Scan to discover Bluetooth device

Pair with Bluetooth device

Connect with SPP

In one shell/terminal - pipe the input from the Bluetooth device to a file

     less -f /dev/rfcomm0 then ctrl+F
or
     tail -f /dev/rfcomm0
or
     cat /dev/rfcomm0 > datalog.txt

In another shell/terminal - echo some command to the Bluetooth device

     echo "8;" > /dev/rfcomm0

Quit the cat command

Inspect the output

     less datalog.txt

Windows Soft Link

mklink (a windows softlink)

Manifest classpath

Message Digest

MD5 throughput was ~15 GBytes/minute on a quad core Intel i5 @ 2.67GHz running Ubuntu Linux 10.04 and Java(TM) SE Runtime Environment (build 1.6.0_22-b04) Java HotSpot(TM) Server VM (build 17.1-b03, mixed mode)

The throughput was the same whether the digest was computed from bytes on disk or memory. org.apache.commons.codec.digest.DigestUtils org.apache.commons.codec.binary.Hex

From file
String filename = "src/test/resources/somefile"; is = new FileInputStream(filename); assertEquals("bd6b1dc1ac767b018003572a767d2d0d", DigestUtils.md5Hex(is)); Pipe filter stream
is = new DigestInputStream( new BufferedInputStream(new FileInputStream(filename)), MessageDigest.getInstance("MD5")); /* * Implementations using DigestInputStream would not need the byte handling as it would be just one filter in a pipe * that is being pumped for some other purpose. */ final byte[] buf = new byte[2048]; while (dis.read(buf) == -1) …