operating-system

What operating systems won't free memory on program exit?

This question made me curious. Questions like this always get answers like "It's generally safe but you shouldn't assume that the OS will do this for you", which sounds like good advice to me, but I'm wondering: Are there any actively-developed (released) operating systems that don't do this? Is this something that was fixed back in the...

Is there anything like standard IP camera OS emulator?

Is there anything like standard IP camera OS emulator? So to create a plugin\program for it and be able to come to Cameras creator\vendor with something like "Hey, I've developed some cool software for your camera! Look here! Please implement it into your cameras next version or please give me the job in your company!)" So something li...

How to power down the computer from a freestanding environment?

I'm making a protected-mode OS based on Intel's x86 architecture, and was looking for some information on how to power off the computer via assembly code, or something like that. Could you help me with this problem? ...

Is heap memory a common memory location shared by different processes?

Every process can use heap memory to store and share data within the process. We have a rule in programming whenever we take some space in heap memory, we need to release it once job is done, else it leads to memory leaks. int *pIntPtr = new int; . . . delete pIntPtr; My question is, will the heap memory exist when the application/pro...

Supporting 64bit OS which currently works in 32 bit OS.

I have an application which has many services and one UI module. All these are developed in VC++ 6.0. The total KLOC would be 560 KLOC. It uses Mutltithreading,MFC and all datatypes like word,int, long. Now we need to support 64bit OS. What would be the changes we would need to make to the product. By support i mean both like running...

memory layout hack

i have been following this course in youtube and it was talking about how some programmers can use there knowledge of how memory is laid to do clever things.. one of the examples in the lecture was something like that #include <stdio.h> void makeArray(); void printArray(); int main(){ makeArray(); printArray(); r...

How can I detect the browser version with JS?

I need to detect the OS version with JS not just the OS type. Is this possible? ...

The future of Singularity.

Some time ago, Microsoft released a research OS called Singularity which had a number of very interesting and innovative ideas an concept. One of the components that I found particularly intriguing was the C#-ish compiler, Spec#, that could compile C# code into native machine code. I was wondering if this project was still continuing? ...

PyQt4 libraries and installation on Mac OS

Hello everyone, it has been a while now I'm surfing the net trying to find the way to sucessfully install PyQt4 on different Mac OS's and I can't figure it out. Does anybody know if there is out there a package I could easily install without having to go through the compiling? I'm developing sone Python tools with PyQt guis and the ide...

can I have a virtual memory smaller than physical memory like for example 2GB of virtual memory and 4GB of Physical Memory(not with respect to usage)?

This has been asked in an interview ...

How would you compare a Scala-based web server with other web frameworks?

I have read about Scala but have not been able to do comparative analysis of other web programming frameworks on the basis of: maintainability (does the Scala language facilitate the maintainability of such a web framework, compared to, say, a Php-based one?), scalability (what OS is best adapted for a Scala wab server to be scalable?)...

Does a file read from a Java application invoke a system call?

My understanding is that a user application requesting a file system path (eg. /aFile) will invoke the File System and get back the virtual address of the requested file. Then the application will attempt a read/write operation with that address as argument, that as a CPU instruction? On execution of the read command the Memory Managemen...

Why can't DMBSes rely on the OS buffer pool?

Stonebraker's paper (Operating System Support for Database Management) explains that, "the overhead to fetch a block from the buffer pool manager usually includes that of a system call and a core-to-core move." Forget about the buffer-replacement strategy, etc. The only point I question is the quoted. My understanding is that when a DBM...

Difference between sem_init and sema_init

What is the difference between sema_init and sem_init ? Are there any specific usage scenarios and other dependencies for the respective APIs ? ...

execve() and sharing file descriptors

I read from man pages of execve that if a process(A) call execve, the already opened file descriptors are copied to the new process(B). Two possiblities arise here :- 1) Does it mean that a new file descriptor table is created for process B, the entries to which are copied from older file descriptor table of process A 2) Or process B ...

Basic question regarding ROM based executable

Dear Pundits, I have basic doubt regarding executable stored in ROM. As I know the executable with text and RO attributes is stored in ROM. Question is as ROM is for Read Only Memory, what happens if there is situation where the code needs to write into memory? I am not able to conjure up any example to cite here (probably I am ignor...

types of buffers

Hello guys, Recently an interviewer asked me about the types of buffers. What types of buffers are there ? Actually this question came up when I said I will be writing all the system calls to a log file to monitor the system. He said it will be slow to write each and every call to a file. How to prevent it. I said I will use a buffer an...

Video with iPhone 3.0 OS application getting crash while running in iphone 4.0 OS.

Hi, I am having a crash issue while playing video in iphone 4.0 OS. Actually, I have created application with base SDK 3.0 and now i am just installing application to 4.0 OS device. It is not working in that... I have debugged that issue and found that in 4.0 OS, apple change the framework and methods to play the video. Any one help m...

Showing page based on operating system with NSIS

I'm working on an NSIS script in which I have two directory pages. One gets the directory for the program install, and one gets the directory for putting any data. The reason for this, is that with some of the control issues in windows 7 and vista involving the Program Files folder, I want the data to be placed outside of the Program Fi...

Where is the location of the OS X 10.5 user wallpaper

I was just wondering where the /File/System/Location/ of a users current wallpaper is stored in OS X 10.5. Something like how the default login windows wallpaper is stored at /System/Library/CoreServices/DefaultDesktop.jpg ...