memorymapping

How to map caller memory in a Windows CE device driver past the end of a call to XXX_IOControl?

I'm implementing a ioctl in a Windows CE device driver that takes a pointer to a large chunk of application memory to perform asynchronous I/O initiated through an application call to DeviceIoControl. When using MapCallerPtr(), the pointer gets unmapped when the XXX_IOControl function returns; when the pointer is used in the IST it is ...

Shell Extension - Virtual File Creation

I want to create a file that only resides in memory... In looking through some documentation I saw a recommendation to use a shell extension as a virtual file. Im not sure that is a workable solution but I would like to know Is it a good approach (or should I be using a ramdisk instead) Where is a good place to start to read up on it...

Binary search in a sorted (memory-mapped ?) file in Java

I am struggling to port a Perl program to Java, and learning Java as I go. A central component of the original program is a Perl module that does string prefix lookups in a +500 GB sorted text file using binary search (essentially, "seek" to a byte offset in the middle of the file, backtrack to nearest newline, compare line prefix with ...

Memory-mapped files in Java

I've been trying to write some very fast Java code that has to do a lot of I/O. I'm using a memory mapped file that returns a ByteBuffer: public static ByteBuffer byteBufferForFile(String fname){ FileChannel vectorChannel; ByteBuffer vector; try { vectorChannel = new FileInputStream(fname).getChannel(); } catch (...

Opening a custom file on-demand

I have a custom file type that is implemented in sections with a header at the shows the offset and length of each section within the file. Currently, whenever I want to interact with the file, I must either load and parse the entire thing up front, or else pick only the sections that I need and load just them. What I would like to do ...

how to get the memory mapping for a core on Linux/HPUX (pmap)

On solaris i can run the pmap command on a core file to get the memory map of a crashed process. Unfortunately the pmap command available on HPUX and Linux doesn't provide this option. Any pointers how i can get this information on these platforms? Thanks! ...

Memory mapped files causes low physical memory

I have a 2GB RAM and running a memory intensive application and going to low available physical memory state and system is not responding to user actions, like opening any application or menu invocation etc. How do I trigger or tell the system to swap the memory to pagefile and free physical memory? I'm using Windows XP. If I run the s...

Java GZip an object and serialize it using MappedByteBuffer

I'm serializing a large 3d array to disk.The original data is around 50MB and GZiped output is in Kb's size.But the operation takes around 5 sec's.I would like to optimize it for time.I was thinking weather it would be any better to use a mapped read/write since i have seen it has better performance than the usual stream writing.But don...