ram

is it possible, in C++, to get the current RAM and CPU usage? Is there a platform-indepentent function call? There is an open source library that gives these (and more system info stuff) across many platforms: SIGAR API I've used it in fairly large projects and it works fine (except for certain corner cases on OS X etc.) Sadly these things rely heavily on the underlying OS, so there are no platform-independent calls. (Maybe there are some wrapper frameworks, but I don't know of any.) On Linux you could have a look at the getrusage() function call, on Windows you can use GetProcessMemoryInfo()

How does the RAM required to store data in memory compare to the disk space required to store the same data in a file? Or is there no generalized correlation? For example, say I simply have a billion floating point values. Stored in binary form, that'd be 4 billion bytes or 3.7GB on disk (not including headers and such). Then say I read those values into a list in Python... how much RAM should I expect that to require? Python Object Data Size If the data is stored in some python object, there will be a little more data attached to the actual data in memory. This may be easily tested. It is

I am often confused with the concept of virtualization in operating systems. Considering RAM as the physical memory, why do we need the virtual memory for executing a process? Where does this virtual memory stand when the process (program) from the external hard drive is brought to the main memory (physical memory) for the execution. Who takes care of the virtual memory and what is the size of the virtual memory? Suppose if the size of the RAM is 4GB (i.e. 2^32-1 address spaces) what is the size of the virtual memory? Virtual memory is, among other things, an abstraction to give the programmer

How does VBulletin get the system information without the use of exec ? Is there any other information I can get about the server without exec? I am interested in: bandwidth used system type CPU speed/usage/count RAM usage Use PHPSysInfo library phpSysInfo is a open source PHP script that displays information about the host being accessed. It will displays things like: Uptime CPU Memory SCSI, IDE, PCI Ethernet Floppy Video Information It directly parsed parses /proc and does not use exec . Another way is to use Linfo . It is a very fast cross-platform php script that describes the host server

记录几种 RAM 和 ROM 的区别： 先说RAM吧！！ 由字面意思就可以理解，SDRAM SRAM DRAM都可以统称RAM，random access memory的缩写，只是前面加了几个修饰词而已。 SRAM： 　　静态随机存储器，就是它不需要刷新电路，不像动态随机存储器那样，每隔一段时间就要刷新一次数据。但是他集成度比较低，不适合做容量大的内存，一般是用在处理器的缓存里面。像S3C2440的ARM9处理器里面就有4K的SRAM用来做CPU启动时用的。 SDRAM： 　　同步动态随机存储器，像电脑的内存就是用的这种RAM叫DDR SDRAM。其集成度非常高，因为是动态的，所以必须有刷新电路，每隔一段时间必须得刷新数据。其存储单元不是按线性排列的，是分页的。一般的嵌入式产品里面的内存都是用的SDRAM。 DRAM： 　　动态随机存储器，SDRAM只是其中的一种吧，没用过，不怎么清楚。 ROM ：只读存储器的总称。 PROM： 　　可编程只读存储器，只能写一次，写错了就得报废，现在用得很少了，好像那些成本比较低的OPT单片机里面用的就是这种存储器吧。 EPROM： 　　可擦除可编程存储器，这东西也比较古老了，是EEPROM的前身，在芯片的上面有个窗口，通过紫外线的照射来擦除数据。非常之麻烦。 EEPROM： 电可擦除可编程只读存储器，比之EPROM就先进点了