I have searched some posts and cannot find what the maximum filesize is under iPhone.
max size of an iOS application
maximum size of sqlite or database on iOS
As the above posts said, the maximum filesize depends on the free disk space. So, can I store everything into sqlite file and it's filesize can exceed 4GB or 10GB ?
According to the following links I found,
Mac OS, HFS File System volumn and file limits
iOS filesystem, HFSX
HFS, Wiki
As the first link says, "The theoretical maximum file size for a Mac OS Extended file system is millions of terabytes. In practice, the maximum file size is equivalent to the maximum volume size, except for a small amount of disk space reserved for file system information."
Because the maximum filesize is equal to the maximum volumn size, and consider the factor about the free disk space.
So, in my conclusion, the maximum size of single file depends on the free disk space.
Related
Most posts i read just give info about the maximum file name length's. But, i want to understand why there's this limit. Why can't file name's be big. I see that few file systems have put a limit of 255 bytes. Why not 1 MB or anything more than 255 bytes. I probably would never have a file name of length more than 100 characters. But, this question is about why the limit?
long file name costs much more space and time than you can imagine
the 255 bytes limit of file name length is a long time trade off between human
onvenience and space/time efficiency
and backward compatibility , of course
back to the dark old days , the capacity of hard drive capacity was count by MB or a few GB
file name are often stored in some fixed length C structs ,
and the size of the struct was mostly round by the factor of 512 byte,
which is the size of a physical sector ,so that it can be read out by a single touch of the head
if the file system put a limit of 1MB on filename, it would run out of harddisk space with only a few hundred files. and memory limits also applys.....
Is there a maximum limit to the amount of metadata that can be incorporated in an individual field of TIFF file metadata? I'd like to store a large text (up to a few MB) in the ImageDescription field.
There's no specific maximum limit to the ImageDescription field, however, there's a maximum file size for the entire TIFF file. This maximum size is 4 GB. From the TIFF 6.0 spec:
The largest possible TIFF file is 2**32 bytes in length.
This is due to the offsets in the file structure, stored as unsigned 32 bit integers.
Thus, the theoretical maximum size is that which #cgohlke points out in the comments ("2^32 minus the offset"), but most likely you want to keep it smaller, if you also intend to include pixel data...
Storing "a few MB" should not be a problem.
We have created Automation Projects using Katalon Studio..
Currently The project folder size is it shows like:
Size: 1.61 MB
Size on Disk: 4.45 MB
Contains: 1033 Files, 444 Folders
How to reduce the difference between Size and Size on Disk.. When project grows is it needs to be sorted out?
This is probably related to your disk cluster size. Files can be no smaller than the cluster size, which is usually somewhere in the range of a few KB. For example, if your cluster size is 4KB then a 1 byte file will still take up 4KB on the disk. Generally this is more noticeable when you have many small files. If you want to change this you will need to reformat your filesystem and choose a smaller cluster size.
From what I learn this far, inodes are the maximum file (and directory) you can have in single partition. You can fill the whole disk inodes without actually filling the disk space, or you can fill the disk space with one very big files, leaving inodes unused.
This question has come into my mind recently: where are those numbers coming from?
You did not mention a specific file system so I am going to assume ext4, although what I am saying should mostly apply to ext3 as well.
The number of inodes is determined when the file-system is created. File-systems are generally written to be flexible enough so that this number can be specified at creation to better suit the needs of the system. So if you have a lot of small files you can create more inodes and if you have a smaller number of large files you can create less inodes.
With mkfs.ext4 you can use the -i flag to specify the bytes per inode. The default value as of now is typically 16384 bytes per inode. This number is nothing specifically special but if you assume the typical 256 bytes for the inode size and 16384 bytes per inode you get approximately 1.56% of the disk space being used by inodes.
What limits the size of a memory-mapped file? I know it can't be bigger than the largest continuous chunk of unallocated address space, and that there should be enough free disk space. But are there other limits?
You're being too conservative: A memory-mapped file can be larger than the address space. The view of the memory-mapped file is limited by OS memory constraints, but that's only the part of the file you're looking at at one time. (And I guess technically you could map multiple views of discontinuous parts of the file at once, so aside from overhead and page length constraints, it's only the total # of bytes you're looking at that poses a limit. You could look at bytes [0 to 1024] and bytes [240 to 240 + 1024] with two separate views.)
In MS Windows, look at the MapViewOfFile function. It effectively takes a 64-bit file offset and a 32-bit length.
This has been my experience when using memory-mapped files under Win32:
If your map the entire file into one segment, it normally taps out at around 750 MB, because it can't find a bigger contiguous block of memory. If you split it up into smaller segments, say 100MB each, you can get around 1500MB-1800MB depending on what else is running.
If you use the /3g switch you can get more than 2GB up to about 2700MB but OS performance is penalized.
I'm not sure about 64-bit, I've never tried it but I presume the max file size is then limited only by the amount of physical memory you have.
Under Windows: "The size of a file view is limited to the largest available contiguous block of unreserved virtual memory. This is at most 2 GB minus the virtual memory already reserved by the process. "
From MDSN.
I'm not sure about LINUX/OSX/Whatever Else, but it's probably also related to address space.
Yes, there are limits to memory-mapped files. Most shockingly is:
Memory-mapped files cannot be larger than 2GB on 32-bit systems.
When a memmap causes a file to be created or extended beyond its current size in the filesystem, the contents of the new part are unspecified. On systems with POSIX filesystem semantics, the extended part will be filled with zero bytes.
Even on my 64-bit, 32GB RAM system, I get the following error if I try to read in one big numpy memory-mapped file instead of taking portions of it using byte-offsets:
Overflow Error: memory mapped size must be positive
Big datasets are really a pain to work with.
The limit of virtual address space is >16 Terabyte on 64Bit Windows systems. The issue discussed here is most probably related to mixing DWORD with SIZE_T.
There should be no other limits. Aren't those enough? ;-)