Device Files is a small Java and C library for extracting vendor info, serial number and size for whole disk drives, such as that named /dev/sda on Linux or C: on Windows. Build is via Maven. The native C parts (which do most of the work) are organized around the 'Java native loader' framework available at (https://github.com/uw-dims/java-native-loader/tree/master).

This repository currently contains native builds for the included C code under [Linux] (./src/main/native/Linux/Makefile) only (both 32-bit and 64-bit builds are done). Still to be done are Mac OS and Windows native builds.

$ cd /path/to/device-files

$ mvn test

$ mvn install

$ mvn javadoc:javadoc

The javadoc step should leave the api docs in target/site/apidocs/.

The main class is DeviceFile. There are also simple unit tests under the [usual Maven location] (./src/test/java).

Use of the DeviceFile class enables access to vendor, product and serial number information about disk drives:

java.io.File f = new java.io.File( "/dev/sda" );
DeviceFile df = new DeviceFile( f );
String serialNumber = df.serialNumber();

The getID() call returns a string much like that in /dev/disk/by-id/ on Linux:

String id = df.getID();

The Device Files Maven project also highlights the use of the [Java Native Loader] (https://github.com/uw-dims/java-native-loader/tree/master) framework. Aspects of this framework include:

• The local [pom] (./pom.xml) shows how we use profiles to canonicalize the results of Maven's 'activation/arch' property (which itself delegates to ${os.arch}) to match the scheme used in the [Native Loader] (https://github.com/uw-dims/java-native-loader/blob/master/main/src/main/java/edu/uw/apl/nativelibloader/OSInfo.java). For example, amd64 maps to x86_64.

• The pom also shows how use of a 'native' profile ensures that only a power user need build the native C code on any given platform. A regular Maven user builds and tests just the Java classes.

• The pom also shows how we define PREFIX and LIBNAME values and pass those down to the platform-dependent build as environment variables. For Linux, the platform-dependent build is a [Makefile] (src/main/native/Linux/Makefile).

• The result of the native build is a platform (+ bitness) specific library file which becomes a Maven resource, so is bundled into the jar, from where it can be loaded by the native loader. An example is at (src/main/resources/edu/uw/apl/commons/devicefiles/native/Linux/x86_64/libdevice-files.so)

• The values for PREFIX and LIBNAME in the pom then match those in the NativeLoader API call, which can be seen in the static initializer in the [DeviceFile] (src/main/java/edu/uw/apl/commons/devicefiles/DeviceFile.java).

• The Linux code for drive parameter identification does not work on USB 'thumb' drives. There must be some other kernel entry point for identifying those drives. The GUI tool 'palimpsest' can identify these correctly, so perhaps examine its codebase.

• Build native library on MacOS and Windows platforms.