Lets say a system stores files in blocks of 16000 bytes. Then calculating the wasted file space from the incomplete filling of the last block for a file of size 4,064,0000 bytes and 640,000 bytes..
Divide them by 16000 and I get NO wasted space...What am I doing wrong?
Related
I am trying to understand, how does the inode pointer work. Suppose I have the following file structure with 512 byte block size. How will the pointer read the file, if the file partially occupies the 14th block - will it read the whole 14th block (all 128x128 blocks), or will it read only non-empty blocks?
Consider a file system that uses contiguous allocation method. For a disk
consists of 100 data blocks, each block is 4KB. What is the maximum and
minimum number of files of size 15KB can it save? Find the number of files the
disk able to support using (1) link allocation and (2) index allocation, assuming
the address is 32 bit
I'm writing a piece of code for an embedded system (mcu Cortex-M4 with very limited ram < 32KB) where I need big chunks of memory for a very small and defined time and I thought to use some kind of a memory pool so the memory won't get wasted for functions and actions that run once or twice a lifetime.
I made some efforts but I think I'd like to learn more about memory pools and rewrite my code better.
I saw some examples where a pointer is used to point to the next available free chunk, but I don't understand how I can process those kind of pools.
For example, I can't use strstr in a memory pool where the total string would be spread into more than one chunk. I would need to read chunk by chunk and store the total string into one larger array to carry on further process. Please correct me if I'm wrong.
So, if I get it right, if I have a memory pool of 1024 bytes with 32 bytes long for each chunk that gives us 32 chunks in total. And if I want to store a string of total length let's say 256 chars (bytes) I'd need 8 chunks but if I want to read the string I'd need to copy those 8 chunks into a 256 chars array.
Am I missing something?
We've just began the topic of cache, memory mapping, and address structure and I am confused on how to find the cache size for this question.
If a cache size is given to you as 128 blocks, and memory has 16kb block of 8 words each, where a word is 4 bytes, does it mean that each cache block is also 8 words each? Or does it mean that we have to divide 128 into 8 to get the actual number of cache blocks? In that case what would the size of the cache be? Would it equal 128*8*4 in bytes?
I have a 4GB Ram installed on Coure2Duo PC with a 32bit Windows 7 Operating system. I have increased the paging size up to 106110MB. But after doing all this I am not able to significantly increase the maximum array size.
Following are the specs
memory
Maximum possible array: 129 MB (1.348e+08 bytes) *
Memory available for all arrays: 732 MB (7.673e+08 bytes) **
Memory used by MATLAB: 563 MB (5.899e+08 bytes)
Physical Memory (RAM): 3549 MB (3.722e+09 bytes)
* Limited by contiguous virtual address space available.
** Limited by virtual address space available.
Kindly help me on your earliest. I am not even able to read a file of 48+MB size in double format.
There are two things you can do to clear up memory for MATLAB. Since you're using a 32-bit version of the program, you're normally limited to 2GB of memory. Using the /3GB switch while opening the program makes an additional 1GB of RAM available to that program.
Second, you should consider using the pack() function, which rearranges variables in RAM to free up more contiguous memory space. This, more than anything, is affecting your ability to open individual arrays.
Remember: you can figure out how many items an array will hold by dividing the memory amount available by the size of the variable type. Double variables take up 8 bytes each. Your 129MB of space available should allow around 16.85 million double values in a single array.
You can view information about memory usage using the memory functions included in MATLAB.
memory shows the memory information
inmem will show you the variables and functions stored in memory
clear will allow you to clear the memory of specific variables or functions.
You may try to set the 3GB switch, maybe this increases the possible memory. Otherwise: Switch to a 64 bit os. Your system wastes 547MB of RAM simply because there are no addresses for it.