Cache Drive Selection

I only have 5 GB of space set on my C:\ drive, which was set up to only provide enough
space for windows to operate reliably without having to defragment it every ten days.

4GB of this space is taken up by Windows; but I have other drives totalling a collective amount of 1.45 TB: Why can I not select where the cache for second life is placed?

If there is a method for doing so, please post it so that this Linden may further prevent fragmentation of his Windows OS file-drive. Thanks.

Oooh, this would be great for me too.
My C: drive is only 15 GB, so I have less of an issue, but I recently became the refuge for a website that lost hosting and most of my C: space disapeared for hosting (as the server software refused to be installed anywhere BUT C: )

I am sure that this is not the answer you are looking for, but the client source code could be hard-coded to use a new and different location for your temporary files.

The change would need to be done in this code block:

lldir_win32.cpp

LLDir_Win32::LLDir_Win32()
{
	mDirDelimiter = "\\";

	WCHAR w_str[MAX_PATH];

	// Application Data is where user settings go
	SHGetSpecialFolderPath(NULL, w_str, CSIDL_APPDATA, TRUE);

	mOSUserDir = utf16str_to_utf8str(llutf16string(w_str));

	// Local Settings\Application Data is where cache files should
	// go, they don't get copied to the server if the user moves his
	// profile around on the network. JC
	//
	// TODO: patch the installer to remove old cache files on update, then
	// enable this code.
	//SHGetSpecialFolderPath(NULL, w_str, CSIDL_LOCAL_APPDATA, TRUE);
	//mOSUserCacheDir = utf16str_to_utf8str(llutf16string(w_str));

	if (GetTempPath(MAX_PATH, w_str))
	{
		if (wcslen(w_str))
		{
			w_str[wcslen(w_str)-1] = '\0'; // remove trailing slash
		}
		mTempDir = utf16str_to_utf8str(llutf16string(w_str));
	}
	else
	{
		mTempDir = mOSUserDir;
	}

//	fprintf(stderr, "mTempDir = <%s>",mTempDir);
[....CUT.....]

You might try the First Look viewer - it has a relocatable cache, on the Preferences General tab.

But I thought that the Viewer did not have anywhere near the functionality of the Second Life Main Client Engine; that's where the problem is--why do I need to use the Viewer for a problem that continuously pops up when I'm building on my lot?

Notes:
1) The term "viewer" applies to all four: First Look, Main, Beta, and Open Source.
2) The First Look Viewer supplies all the same functionality that the Main Viewer has, just some differences, test features (mirrors, relocatable cache, new rendering pipelines, etc)

Given that, how does the cache location issue only crop up while you're building? If that's not the problem, then what are you talking about?