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Zip using C# of same file produces output zip of different size on server and windows 10

There is one dll and if we zip it on windows 10 and windows server 2012 using same code, it produces different size. Size difference is exactly 5 bytes. C# code is
private static void Zip()
{
var fileInfo = new FileInfo(#"C:\USB\adammigrate.dll");
using (Stream stream = File.Open(#"C:\USB\adammigrate.dll", FileMode.Open, FileAccess.Read, FileShare.Read))
using (var zipArchive = ZipFile.Open(#"C:\USB\adammigrate1.zip", ZipArchiveMode.Create))
{
var entry = zipArchive.CreateEntry("adammigrate.dll", CompressionLevel.NoCompression);
entry.LastWriteTime = fileInfo.LastWriteTime.ToUniversalTime();
using (Stream stream2 = entry.Open())
{
var buffer = new byte[BufferSize];
int numBytesRead;
while ((numBytesRead = stream.Read(buffer, 0, buffer.Length)) > 0)
{
stream2.Write(buffer, 0, numBytesRead);
}
}
}
}
Size on disk is same but actual size is differ by 5 bytes. PFA Zip Info for both the zip files.

The zip format is not guaranteed to have a single representation; it can be different sizes depending on specifics of the implementation (i.e. multiple encoding options are available, and it may or may not choose the absolute best one). The only important question is: does it unzip back to the original content? If it fails to unzip, then it is interesting. But being different sizes by itself doesn't mean anything.
If you want an absolute guarantee of getting the exact same zip output, you'll have to find an implementation that offers output stability as a documented feature; the implementation you're using clearly doesn't offer that. Usually tools like zip want to retain the ability to quietly improve their choices for your benefit between versions (and sometimes it might try to make things better generally, with the side-effect that sometimes it makes it worse).
If you were anticipating always getting the exact same bytes back: then zip is probably not an appropriate file format for you, unless you only compare the sizes and contents of the internal payloads (i.e. what they would be once decompressed), not the zip file itself.

C# Loading text data into WPF control

I am searching for a very fast way of loading text content from a 1GB text file into a WPF control (ListView for example). I want to load the content within 2 seconds.
Reading the content line by line takes to long, so I think reading it as bytes will be faster. So far I have:
byte[] buffer = new byte[4096];
int bytesRead = 0;
using(FileStream fs = new FileStream("myfile.txt", FileMode.Open, FileAccess.Read, FileShare.ReadWrite)) {
while((bytesRead = fs.Read(buffer, 0, buffer.Length)) > 0) {
Encoding.Unicode.GetString(buffer);
}
}
Is there any way of transforming the bytes into string lines and add those to a ListView/ListBox?
Is this the fastest way of loading file content into a WPF GUI control? There are various applications that can load file content from a 1GB file within 1 second.
EDIT: will it help by using multiple threads reading the file? For example:
var t1 = Task.Factory.StartNew(() =>
{
//read content/load into GUI...
});
EDIT 2: I am planning to use pagination/paging as suggested below, but when I want to scroll down or up, the file content has to be read again to get to the place that is being displayed.. so I would like to use:
fs.Seek(bytePosition, SeekOrigin.Begin);
but would that be faster than reading line by line, in multiple threads? Example:
long fileLength = fs.Length;
long halfFile = (fileLength / 2);
FileStream fs2 = fs;
byte[] buffer2 = new byte[4096];
int bytesRead2 = 0;
var t1 = Task.Factory.StartNew(() =>
{
while((bytesRead += fs.Read(buffer, 0, buffer.Length)) < (halfFile -1)) {
Encoding.Unicode.GetString(buffer);
//convert bytes into string lines...
}
});
var t2 = Task.Factory.StartNew(() =>
{
fs2.Seek(halfFile, SeekOrigin.Begin);
while((bytesRead2 += fs2.Read(buffer2, 0, buffer2.Length)) < (fileLength)) {
Encoding.Unicode.GetString(buffer2);
//convert bytes into string lines...
}
});

Using a thread won't make it any faster (technically there is a slight expense to threads so loading may take slightly longer) though it may make your app more responsive. I don't know if File.ReadAllText() is any faster?
Where you will have a problem though is data binding. If say you after loading your 1GB file from a worker thread (regardless of technique), you will now have 1GB worth of lines to databind to your ListView/ListBox. I recommend you don't loop around adding line by line to your control via say an ObservableCollection.
Instead, consider having the worker thread append batches of items to your UI thread where it can append the items to the ListView/ListBox per item in the batch.
This will cut down on the overhead of Invoke as it floods the UI message pump.

Since you want to read this fast I suggest using the System.IO.File class for your WPF desktop application.
MyText = File.ReadAllText("myFile.txt", Encoding.Unicode); // If you want to read as is
string[] lines = File.ReadAllLines("myFile.txt", Encoding.Unicode); // If you want to place each line of text into an array
Together with DataBinding, your WPF application should be able to read the text file and display it on the UI fast.
About performance, you can refer to this answer.
So use File.ReadAllText() instead of ReadToEnd() as it makes your code
shorter and more readable. It also takes care of properly disposing
resources as you might forget doing with a StreamReader (as you did in
your snippet). - Darin Dimitrov
Also, you must consider the specs of the machine that will run your application.

When you say "Reading the content line by line takes to long", what do you mean? How are you actually reading the content?
However, more than anything else, let's take a step back and look at the idea of loading 1 GB of data into a ListView.
Personally you should use an IEnumerable to read the file, for example:
foreach (string line in File.ReadLines(path))
{
}
But more importantly you should implement pagination in your UI and cut down what's visible and what's loaded immediately. This will cut down your resource use massively and make sure you have a usable UI. You can use IEnumerable methods such as Skip() and Take(), which are effective at using your resources effectively (i.e. not loading unused data).
You wouldn't need to use any extra threads either (aside from the background thread + UI thread), but I will suggest using MVVM and INotifyPropertyChanged to skip worrying about threading altogether.

Copy in c# is very slow

I am trying to copy a lot of files using a loop and CopyTo method.
The copy is very slow. abot 10 mb per minute! (in contrast to right click in mouse and copy).
Is there any alternatives to use, which are faster?

Yes, use FileStream to buffer accordingly. As an example, something along the lines of this ought to give you an idea:
using (var inputStream = File.Open(path, FileMode.Read),
outputStream = File.Open(path, FileMode.Create))
{
var bufferRead = -1;
var bufferLength = 4096;
var buffer = new byte[bufferLength];
while ((bufferRead = inputStream.Read(buffer, 0, bufferLength)) > 0)
{
outputStream.Write(buffer, 0, bufferRead);
}
}
Adjust the bufferLength accordingly. You could potentially build things around this to enhance its overall speed, but tweaking slightly should still provide a significant enough improvement.

I think this will help:
File.Copy vs. Manual FileStream.Write For Copying File
It also explains why the copy function is slow.

The fastest (and most convenient) way to copy a file is probably File.Copy. Is there a reason you are not using it?

Joining Binary files that have been split via download

I am trying to join a number of binary files that were split during download. The requirement stemmed from the project http://asproxy.sourceforge.net/. In this project author allows you to download files by providing a url.
The problem comes through where my server does not have enough memory to keep a file that is larger than 20 meg in memory.So to solve this problem i modified the code to not download files larger than 10 meg's , if the file is larger it would then allow the user to download the first 10 megs. The user must then continue the download and hopefully get the second 10 megs. Now i have got all this working , except when the user needs to join the files they downloaded i end up with corrupt files , as far as i can tell something is either being added or removed via the download.
I am currently join the files together by reading all the files then writing them to one file.This should work since i am reading and writing in bytes. The code i used to join the files is listed here http://www.geekpedia.com/tutorial201_Splitting-and-joining-files-using-C.html
I do not have the exact code with me atm , as soon as i am home i will post the exact code if anyone is willing to help out.
Please let me know if i am missing out anything or if there is a better way to do this , i.e what could i use as an alternative to a memory stream. The source code for the original project which i made changes to can be found here http://asproxy.sourceforge.net/download.html , it should be noted i am using version 5.0. The file i modified is called WebDataCore.cs and i modified line 606 to only too till 10 megs of data had been loaded the continue execution.
Let me know if there is anything i missed.
Thanks

You shouldn't split for memory reasons... the reason to split is usually to avoid having to re-download everything in case of failure. If memory is an issue, you are doing it wrong... you shouldn't be buffering in memory, for example.
The easiest way to download a file is simply:
using(WebClient client = new WebClient()) {
client.DownloadFile(remoteUrl, localPath);
}
Re your split/join code - again, the problem is that you are buffering everything in memory; File.ReadAllBytes is a bad thing unless you know you have small files. What you should have is something like:
byte[] buffer = new byte[8192]; // why not...
int read;
while((read = inStream.Read(buffer, 0, buffer.Length)) > 0)
{
outStream.Write(buffer, 0, read);
}
This uses a moderate buffer to pump data between the two as a stream. A lot more efficient. The loop says:
try to read some data (at most, the buffer-size)
(this will read at least 1 byte, or we have reached the end of the stream)
if we read something, write this many bytes from the buffer to the output

In the end i have found that by using a FTP request i was able to get arround the memory issue and the file is saved correctly.
Thanks for all the help

That example is loading each entire chunk into memory, instead you could do something like this:
int bufSize = 1024 * 32;
byte[] buffer = new byte[bufSize];
using (FileStream outputFile = new FileStream(OutputFileName, FileMode.OpenOrCreate,
FileAccess.Write, FileShare.None, bufSize))
{
foreach (string inputFileName in inputFiles)
{
using (FileStream inputFile = new FileStream(inputFileName, FileMode.Append,
FileAccess.Write, FileShare.None, buffer.Length))
{
int bytesRead = 0;
while ((bytesRead = inputFile.Read(buffer, 0, buffer.Length)) != 0)
{
outputFile.Write(buffer, 0, bytesRead);
}
}

Copy a file without using the windows file cache

Anybody know of a way to copy a file from path A to path B and suppressing the Windows file system cache?
Typical use is copying a large file from a USB drive, or server to your local machine. Windows seems to swap everything out if the file is really big, e.g. 2GiB.
Prefer example in C#, but I'm guessing this would be a Win32 call of some sort if possible.

In C# I have found something like this to work, this can be changed to copy directly to destination file:
public static byte[] ReadAllBytesUnbuffered(string filePath)
{
const FileOptions FileFlagNoBuffering = (FileOptions)0x20000000;
var fileInfo = new FileInfo(filePath);
long fileLength = fileInfo.Length;
int bufferSize = (int)Math.Min(fileLength, int.MaxValue / 2);
bufferSize += ((bufferSize + 1023) & ~1023) - bufferSize;
using (var stream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.None,
bufferSize, FileFlagNoBuffering | FileOptions.SequentialScan))
{
long length = stream.Length;
if (length > 0x7fffffffL)
{
throw new IOException("File too long over 2GB");
}
int offset = 0;
int count = (int)length;
var buffer = new byte[count];
while (count > 0)
{
int bytesRead = stream.Read(buffer, offset, count);
if (bytesRead == 0)
{
throw new EndOfStreamException("Read beyond end of file EOF");
}
offset += bytesRead;
count -= bytesRead;
}
return buffer;
}
}

Even more important, there are FILE_FLAG_WRITE_THROUGH and FILE_FLAG_NO_BUFFERING.
MSDN has a nice article on them both: http://support.microsoft.com/kb/99794

I am not sure if this helps, but take a look at Increased Performance Using FILE_FLAG_SEQUENTIAL_SCAN.
SUMMARY
There is a flag for CreateFile()
called FILE_FLAG_SEQUENTIAL_SCAN which
will direct the Cache Manager to
access the file sequentially.
Anyone reading potentially large files
with sequential access can specify
this flag for increased performance.
This flag is useful if you are reading
files that are "mostly" sequential,
but you occasionally skip over small
ranges of bytes.

If you dont mind using a tool, ESEUTIL worked great for me.
You can check out this blog entry comparing Buffered and NonBuffered IO functions and from where to get ESEUTIL.
copying some text from the technet blog:
So looking at the definition of buffered I/O above, we can see where the perceived performance problems lie - in the file system cache overhead. Unbuffered I/O (or a raw file copy) is preferred when attempting to copy a large file from one location to another when we do not intend to access the source file after the copy is complete. This will avoid the file system cache overhead and prevent the file system cache from being effectively flushed by the large file data. Many applications accomplish this by calling CreateFile() to create an empty destination file, then using the ReadFile() and WriteFile() functions to transfer the data.
CreateFile() - The CreateFile function creates or opens a file, file stream, directory, physical disk, volume, console buffer, tape drive, communications resource, mailslot, or named pipe. The function returns a handle that can be used to access an object.
ReadFile() - The ReadFile function reads data from a file, and starts at the position that the file pointer indicates. You can use this function for both synchronous and asynchronous operations.
WriteFile() - The WriteFile function writes data to a file at the position specified by the file pointer. This function is designed for both synchronous and asynchronous operation.
For copying files around the network that are very large, my copy utility of choice is ESEUTIL which is one of the database utilities provided with Exchange.

Eseutil is a correct answer, also since Win7 / 2008 R2, you can use the /j switch in Xcopy, which has the same effect.

I understand this question was 11 years ago, nowadays there is robocopy which is kind of replacement for xcopy.
you need to check /J option
/J :: copy using unbuffered I/O (recommended for large files)