Merged changes from dev branch as at version 1.21

7 files changed, 406 insertions, 102 deletions

diff --git a/src/Storage/CRC32.cpp b/src/Storage/CRC32.cpp
new file mode 100644
index 00000000..88142ac9
--- /dev/null
+++ b/src/Storage/CRC32.cpp
@@ -0,0 +1,74 @@
+#include "CRC32.h"
+
+const uint32_t CRC32::CRC_32_TAB[256] = { 
+	/* 
+	CRC polynomial 0xedb88320 
+	This table can also be generated in runtime
+	*/
+	0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
+	0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
+	0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
+	0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
+	0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
+	0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
+	0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
+	0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
+	0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
+	0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
+	0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
+	0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
+	0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
+	0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
+	0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
+	0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
+	0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
+	0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
+	0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
+	0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+	0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
+	0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
+	0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
+	0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
+	0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
+	0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
+	0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
+	0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
+	0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
+	0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
+	0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
+	0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
+	0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
+	0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
+	0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
+	0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
+	0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
+	0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
+	0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
+	0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+	0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
+	0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
+	0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
+};
+
+CRC32::CRC32()
+{
+	Reset();
+}
+
+void CRC32::Update(char c)
+{
+	crc = (CRC_32_TAB[(crc ^ c) & 0xFF] ^ (crc >> 8));
+}
+
+void CRC32::Update(const char *c, size_t len)
+{
+	for (size_t i = 0; i < len; ++i)
+	{
+		Update(c[i]);
+	}
+}
+
+void CRC32::Reset()
+{
+	crc = 0xffffffff;
+}
\ No newline at end of file
diff --git a/src/Storage/CRC32.h b/src/Storage/CRC32.h
new file mode 100644
index 00000000..06bcfe13
--- /dev/null
+++ b/src/Storage/CRC32.h
@@ -0,0 +1,27 @@
+#ifndef CRC32_H
+#define CRC32_H
+
+#include <cstdint> // for uint32_t
+#include <cstddef> // for size_t
+
+class CRC32
+{
+private:
+	static const uint32_t CRC_32_TAB[];
+	uint32_t crc;
+
+public:
+	CRC32();
+	void Update(char c);
+	void Update(const char *c, size_t len);
+	void Reset();
+	uint32_t Get() const;
+
+};
+
+inline uint32_t CRC32::Get() const
+{
+	return ~crc;
+}
+
+#endif
\ No newline at end of file
diff --git a/src/Storage/FileData.h b/src/Storage/FileData.h
index 00c7e47f..683b4165 100644
--- a/src/Storage/FileData.h
+++ b/src/Storage/FileData.h
@@ -19,7 +19,7 @@ class FileData
 public:
 	friend class FileGCodeInput;
 
-	FileData() : f(NULL) {}
+	FileData() : f(nullptr) {}
 
 	// Set this to refer to a newly-opened file
 	void Set(FileStore* pfile)
@@ -28,14 +28,14 @@ public:
 		f = pfile;
 	}
 
-	bool IsLive() const { return f != NULL; }
+	bool IsLive() const { return f != nullptr; }
 
 	bool Close()
 	{
-		if (f != NULL)
+		if (f != nullptr)
 		{
 			bool ok = f->Close();
-			f = NULL;
+			f = nullptr;
 			return ok;
 		}
 		return false;
@@ -46,7 +46,7 @@ public:
 		return f->Read(b);
 	}
 
-	int Read(char* buf, size_t nBytes)
+	int Read(char *buf, size_t nBytes)
 	{
 		return f->Read(buf, nBytes);
 	}
@@ -56,7 +56,17 @@ public:
 		return f->Write(b);
 	}
 
-	bool Write(const char *s, unsigned int len)
+	bool Write(const char *s)
+	{
+		return f->Write(s, strlen(s));
+	}
+
+	bool Write(const char *s, size_t len)
+	{
+		return f->Write(s, len);
+	}
+
+	bool Write(const uint8_t *s, size_t len)
 	{
 		return f->Write(s, len);
 	}
@@ -76,11 +86,6 @@ public:
 		return f->Seek(position);
 	}
 
-	float FractionRead() const
-	{
-		return (f == NULL ? -1.0 : f->FractionRead());
-	}
-
 	FilePosition Length() const
 	{
 		return f->Length();
@@ -91,7 +96,7 @@ public:
 	{
 		Close();
 		f = other.f;
-		if (f != NULL)
+		if (f != nullptr)
 		{
 			f->Duplicate();
 		}
@@ -110,7 +115,7 @@ private:
 
 	void Init()
 	{
-		f = NULL;
+		f = nullptr;
 	}
 
 	// Private assignment operator to prevent us assigning these objects
diff --git a/src/Storage/FileStore.cpp b/src/Storage/FileStore.cpp
index d650da2d..86c24893 100644
--- a/src/Storage/FileStore.cpp
+++ b/src/Storage/FileStore.cpp
@@ -8,8 +8,9 @@
 
 uint32_t FileStore::longestWriteTime = 0;
 
-FileStore::FileStore(Platform* p) : platform(p)
+FileStore::FileStore() : writeBuffer(nullptr)
 {
+	Init();
 }
 
 void FileStore::Init()
@@ -21,13 +22,27 @@ void FileStore::Init()
 }
 
 // Invalidate the file if it uses the specified FATFS object
-void FileStore::Invalidate(const FATFS *fs)
+bool FileStore::Invalidate(const FATFS *fs, bool doClose)
 {
 	if (file.fs == fs)
 	{
-		Init();
-		file.fs = nullptr;
+		if (doClose)
+		{
+			(void)ForceClose();
+		}
+		else
+		{
+			file.fs = nullptr;
+			if (writeBuffer != nullptr)
+			{
+				reprap.GetPlatform().GetMassStorage()->ReleaseWriteBuffer(writeBuffer);
+				writeBuffer = nullptr;
+			}
+			Init();
+		}
+		return true;
 	}
+	return false;
 }
 
 // Return true if the file is open on the specified file system
@@ -38,55 +53,62 @@ bool FileStore::IsOpenOn(const FATFS *fs) const
 
 // Open a local file (for example on an SD card).
 // This is protected - only Platform can access it.
-bool FileStore::Open(const char* directory, const char* fileName, bool write)
+bool FileStore::Open(const char* directory, const char* fileName, OpenMode mode)
 {
-	const char* location = (directory != nullptr)
-							? platform->GetMassStorage()->CombineName(directory, fileName)
-								: fileName;
-	writing = write;
+	const char* const location = (directory != nullptr)
+									? reprap.GetPlatform().GetMassStorage()->CombineName(directory, fileName)
+										: fileName;
+	writing = (mode == OpenMode::write || mode == OpenMode::append);
 
-	// Try to create the path of this file if we want to write to it
 	if (writing)
 	{
-		char filePathBuffer[FILENAME_LENGTH];
-		StringRef filePath(filePathBuffer, FILENAME_LENGTH);
+		// Try to create the path of this file if we want to write to it
+		String<MaxFilenameLength> filePath;
 		filePath.copy(location);
 
-		bool isVolume = isdigit(filePath[0]);
-		for(size_t i = 1; i < filePath.strlen(); i++)
+		size_t i = (isdigit(filePath[0]) && filePath[1] == ':') ? 2 : 0;
+		if (filePath[i] == '/')
+		{
+			++i;
+		}
+
+		while (i < filePath.strlen())
 		{
 			if (filePath[i] == '/')
 			{
-				if (isVolume)
-				{
-					isVolume = false;
-					continue;
-				}
-
 				filePath[i] = 0;
-				if (!platform->GetMassStorage()->DirectoryExists(filePath.Pointer()) && !platform->GetMassStorage()->MakeDirectory(filePath.Pointer()))
+				if (!reprap.GetPlatform().GetMassStorage()->DirectoryExists(filePath.Pointer()) && !reprap.GetPlatform().GetMassStorage()->MakeDirectory(filePath.Pointer()))
 				{
-					platform->MessageF(GENERIC_MESSAGE, "Failed to create directory %s while trying to open file %s\n",
-							filePath.Pointer(), location);
+					reprap.GetPlatform().MessageF(ErrorMessage, "Failed to create directory %s while trying to open file %s\n", filePath.Pointer(), location);
 					return false;
 				}
 				filePath[i] = '/';
 			}
+			++i;
 		}
+
+		// Also try to allocate a write buffer so we can perform faster writes
+		// We only do this if the mode is write, not append, because we don't want to use up a large buffer to append messages to the log file,
+		// especially as we need to flush messages to SD card regularly.
+		// Currently, append mode is used only for the log file.
+		writeBuffer = (mode == OpenMode::write) ? reprap.GetPlatform().GetMassStorage()->AllocateWriteBuffer() : nullptr;
 	}
 
-	FRESULT openReturn = f_open(&file, location, (writing) ?  FA_CREATE_ALWAYS | FA_WRITE : FA_OPEN_EXISTING | FA_READ);
+	const FRESULT openReturn = f_open(&file, location,
+										(mode == OpenMode::write) ?  FA_CREATE_ALWAYS | FA_WRITE
+											: (mode == OpenMode::append) ? FA_WRITE | FA_OPEN_ALWAYS
+												: FA_OPEN_EXISTING | FA_READ);
 	if (openReturn != FR_OK)
 	{
 		// We no longer report an error if opening a file in read mode fails unless debugging is enabled, because sometimes that is quite normal.
 		// It is up to the caller to report an error if necessary.
 		if (reprap.Debug(modulePlatform))
 		{
-			platform->MessageF(GENERIC_MESSAGE, "Can't open %s to %s, error code %d\n", location, (writing) ? "write" : "read", openReturn);
+			reprap.GetPlatform().MessageF(ErrorMessage, "Can't open %s to %s, error code %d\n", location, (writing) ? "write" : "read", openReturn);
 		}
 		return false;
 	}
-
+	crc.Reset();
 	inUse = true;
 	openCount = 1;
 	return true;
@@ -96,12 +118,14 @@ void FileStore::Duplicate()
 {
 	if (!inUse)
 	{
-		platform->Message(GENERIC_MESSAGE, "Error: Attempt to dup a non-open file.\n");
-		return;
+		reprap.GetPlatform().Message(ErrorMessage, "Attempt to dup a non-open file.\n");
+	}
+	else
+	{
+		irqflags_t flags = cpu_irq_save();
+		++openCount;
+		cpu_irq_restore(flags);
 	}
-	irqflags_t flags = cpu_irq_save();
-	++openCount;
-	cpu_irq_restore(flags);
 }
 
 // This may be called from an ISR, in which case we need to defer the close
@@ -114,7 +138,7 @@ bool FileStore::Close()
 			return false;
 		}
 
-		irqflags_t flags = cpu_irq_save();
+		const irqflags_t flags = cpu_irq_save();
 		if (openCount > 1)
 		{
 			--openCount;
@@ -129,11 +153,11 @@ bool FileStore::Close()
 
 	if (!inUse)
 	{
-		platform->Message(GENERIC_MESSAGE, "Error: Attempt to close a non-open file.\n");
+		reprap.GetPlatform().Message(ErrorMessage, "Attempt to close a non-open file.\n");
 		return false;
 	}
 
-	irqflags_t flags = cpu_irq_save();
+	const irqflags_t flags = cpu_irq_save();
 	--openCount;
 	bool leaveOpen = (openCount != 0);
 	cpu_irq_restore(flags);
@@ -143,16 +167,28 @@ bool FileStore::Close()
 		return true;
 	}
 
+	return ForceClose();
+}
+
+bool FileStore::ForceClose()
+{
 	bool ok = true;
 	if (writing)
 	{
 		ok = Flush();
 	}
 
-	FRESULT fr = f_close(&file);
+	if (writeBuffer != nullptr)
+	{
+		reprap.GetPlatform().GetMassStorage()->ReleaseWriteBuffer(writeBuffer);
+		writeBuffer = nullptr;
+	}
+
+	const FRESULT fr = f_close(&file);
 	inUse = false;
 	writing = false;
 	closeRequested = false;
+	openCount = 0;
 	return ok && fr == FR_OK;
 }
 
@@ -160,7 +196,7 @@ bool FileStore::Seek(FilePosition pos)
 {
 	if (!inUse)
 	{
-		platform->Message(GENERIC_MESSAGE, "Error: Attempt to seek on a non-open file.\n");
+		reprap.GetPlatform().Message(ErrorMessage, "Attempt to seek on a non-open file.\n");
 		return false;
 	}
 	FRESULT fr = f_lseek(&file, pos);
@@ -169,7 +205,12 @@ bool FileStore::Seek(FilePosition pos)
 
 FilePosition FileStore::Position() const
 {
-	return file.fptr;
+	return (inUse) ? file.fptr : 0;
+}
+
+uint32_t FileStore::ClusterSize() const
+{
+	return (inUse) ? file.fs->csize * 512u : 1;			// we divide by the cluster size so return 1 not 0 if there is an error
 }
 
 #if 0	// not currently used
@@ -183,21 +224,11 @@ FilePosition FileStore::Length() const
 {
 	if (!inUse)
 	{
-		platform->Message(GENERIC_MESSAGE, "Error: Attempt to size non-open file.\n");
+		reprap.GetPlatform().Message(ErrorMessage, "Attempt to size non-open file.\n");
 		return 0;
 	}
-	return file.fsize;
-}
-
-float FileStore::FractionRead() const
-{
-	FilePosition len = Length();
-	if (len == 0)
-	{
-		return 0.0;
-	}
 
-	return (float)Position() / (float)len;
+	return (writeBuffer != nullptr) ? file.fsize + writeBuffer->BytesStored() : file.fsize;
 }
 
 // Single character read
@@ -211,7 +242,7 @@ int FileStore::Read(char* extBuf, size_t nBytes)
 {
 	if (!inUse)
 	{
-		platform->Message(GENERIC_MESSAGE, "Error: Attempt to read from a non-open file.\n");
+		reprap.GetPlatform().Message(ErrorMessage, "Attempt to read from a non-open file.\n");
 		return -1;
 	}
 
@@ -219,7 +250,7 @@ int FileStore::Read(char* extBuf, size_t nBytes)
 	FRESULT readStatus = f_read(&file, extBuf, nBytes, &bytes_read);
 	if (readStatus != FR_OK)
 	{
-		platform->Message(GENERIC_MESSAGE, "Error: Cannot read file.\n");
+		reprap.GetPlatform().Message(ErrorMessage, "Cannot read file.\n");
 		return -1;
 	}
 	return (int)bytes_read;
@@ -259,6 +290,19 @@ int FileStore::ReadLine(char* buf, size_t nBytes)
 	return i;
 }
 
+FRESULT FileStore::Store(const char *s, size_t len, size_t *bytesWritten)
+{
+	uint32_t time = micros();
+	crc.Update(s, len);
+	FRESULT writeStatus = f_write(&file, s, len, bytesWritten);
+	time = micros() - time;
+	if (time > longestWriteTime)
+	{
+		longestWriteTime = time;
+	}
+	return writeStatus;
+}
+
 bool FileStore::Write(char b)
 {
 	return Write(&b, sizeof(char));
@@ -273,22 +317,42 @@ bool FileStore::Write(const char *s, size_t len)
 {
 	if (!inUse)
 	{
-		platform->Message(GENERIC_MESSAGE, "Error: Attempt to write block to a non-open file.\n");
+		reprap.GetPlatform().Message(ErrorMessage, "Attempt to write block to a non-open file.\n");
 		return false;
 	}
 
-	size_t bytesWritten;
-	uint32_t time = micros();
-
-	FRESULT writeStatus = f_write(&file, s, len, &bytesWritten);
-	time = micros() - time;
-	if (time > longestWriteTime)
+	size_t totalBytesWritten = 0;
+	FRESULT writeStatus = FR_OK;
+	if (writeBuffer == nullptr)
 	{
-		longestWriteTime = time;
+		writeStatus = Store(s, len, &totalBytesWritten);
 	}
-	if ((writeStatus != FR_OK) || (bytesWritten != len))
+	else
 	{
-		platform->Message(GENERIC_MESSAGE, "Error: Cannot write to file. Drive may be full.\n");
+		do
+		{
+			size_t bytesStored = writeBuffer->Store(s + totalBytesWritten, len - totalBytesWritten);
+			if (writeBuffer->BytesLeft() == 0)
+			{
+				const size_t bytesToWrite = writeBuffer->BytesStored();
+				size_t bytesWritten;
+				writeStatus = Store(writeBuffer->Data(), bytesToWrite, &bytesWritten);
+				writeBuffer->DataTaken();
+
+				if (bytesToWrite != bytesWritten)
+				{
+					// Something went wrong
+					break;
+				}
+			}
+			totalBytesWritten += bytesStored;
+		}
+		while (writeStatus == FR_OK && totalBytesWritten != len);
+	}
+
+	if ((writeStatus != FR_OK) || (totalBytesWritten != len))
+	{
+		reprap.GetPlatform().Message(ErrorMessage, "Failed to write to file. Drive may be full.\n");
 		return false;
 	}
 	return true;
@@ -298,9 +362,27 @@ bool FileStore::Flush()
 {
 	if (!inUse)
 	{
-		platform->Message(GENERIC_MESSAGE, "Error: Attempt to flush a non-open file.\n");
+		reprap.GetPlatform().Message(ErrorMessage, "Attempt to flush a non-open file.\n");
 		return false;
 	}
+
+	if (writeBuffer != nullptr)
+	{
+		const size_t bytesToWrite = writeBuffer->BytesStored();
+		if (bytesToWrite != 0)
+		{
+			size_t bytesWritten;
+			const FRESULT writeStatus = Store(writeBuffer->Data(), bytesToWrite, &bytesWritten);
+			writeBuffer->DataTaken();
+
+			if ((writeStatus != FR_OK) || (bytesToWrite != bytesWritten))
+			{
+				reprap.GetPlatform().Message(ErrorMessage, "Failed to write to file. Drive may be full.\n");
+				return false;
+			}
+		}
+	}
+
 	return f_sync(&file) == FR_OK;
 }
 
@@ -319,7 +401,7 @@ bool FileStore::SetClusterMap(uint32_t tbl[])
 {
 	if (!inUse)
 	{
-		platform->Message(GENERIC_MESSAGE, "Error: Attempt to set cluster map for a non-open file.\n");
+		platform->Message(ErrorMessage, "attempt to set cluster map for a non-open file.\n");
 		return false;
 	}
 
diff --git a/src/Storage/FileStore.h b/src/Storage/FileStore.h
index 364bdc8f..5651b0bd 100644
--- a/src/Storage/FileStore.h
+++ b/src/Storage/FileStore.h
@@ -5,57 +5,75 @@
 
 #include "Core.h"
 #include "Libraries/Fatfs/ff.h"
-
-const size_t FileBufLen = 256;						// 512 would be more efficient, but need to free up some RAM first
+#include "CRC32.h"
 
 class Platform;
+class FileWriteBuffer;
+
+enum class OpenMode : uint8_t
+{
+	read,			// open an existing file for reading
+	write,			// write a file, replacing any existing file of the same name
+	append			// append to an existing file, or create a new file if it is not found
+};
 
 class FileStore
 {
 public:
+	FileStore();
+
+    bool Open(const char* directory, const char* fileName, OpenMode mode);
 	bool Read(char& b);								// Read 1 byte
 	int Read(char* buf, size_t nBytes);				// Read a block of nBytes length
 	int ReadLine(char* buf, size_t nBytes);			// As Read but stop after '\n' or '\r\n' and null-terminate
 	bool Write(char b);								// Write 1 byte
 	bool Write(const char *s, size_t len);			// Write a block of len bytes
+	bool Write(const uint8_t *s, size_t len);		// Write a block of len bytes
 	bool Write(const char* s);						// Write a string
 	bool Close();									// Shut the file and tidy up
+	bool ForceClose();
 	bool Seek(FilePosition pos);					// Jump to pos in the file
 	FilePosition Position() const;					// Return the current position in the file, assuming we are reading the file
+	uint32_t ClusterSize() const;					// Cluster size in bytes
+	FilePosition Length() const;					// File size in bytes
 #if 0	// not currently used
 	bool GoToEnd();									// Position the file at the end (so you can write on the end).
 #endif
-	FilePosition Length() const;					// File size in bytes
-	float FractionRead() const;						// How far in we are
+
 	void Duplicate();								// Create a second reference to this file
 	bool Flush();									// Write remaining buffer data
-	void Invalidate(const FATFS *fs);				// Invalidate the file if it uses the specified FATFS object
+	bool Invalidate(const FATFS *fs, bool doClose);	// Invalidate the file if it uses the specified FATFS object
 	bool IsOpenOn(const FATFS *fs) const;			// Return true if the file is open on the specified file system
+	uint32_t GetCRC32() const;
 
 #if 0	// not currently used
 	bool SetClusterMap(uint32_t[]);					// Provide a cluster map for fast seeking
 #endif
 	static float GetAndClearLongestWriteTime();		// Return the longest time it took to write a block to a file, in milliseconds
 
-	friend class Platform;
-
-protected:
-
-	FileStore(Platform* p);
-	void Init();
-    bool Open(const char* directory, const char* fileName, bool write);
+	friend class MassStorage;
 
 private:
-	Platform* platform;
+	void Init();
+	FRESULT Store(const char *s, size_t len, size_t *bytesWritten); // Write data to the non-volatile storage
 
-	FIL file;
+    FIL file;
+	FileWriteBuffer *writeBuffer;
 	volatile unsigned int openCount;
 	volatile bool closeRequested;
 
 	bool inUse;
 	bool writing;
+	CRC32 crc;
 
 	static uint32_t longestWriteTime;
 };
 
+inline bool FileStore::Write(const uint8_t *s, size_t len) { return Write(reinterpret_cast<const char *>(s), len); }
+
+inline uint32_t FileStore::GetCRC32() const
+{
+	return crc.Get();
+}
+
 #endif
diff --git a/src/Storage/FileWriteBuffer.h b/src/Storage/FileWriteBuffer.h
new file mode 100644
index 00000000..d5198e8c
--- /dev/null
+++ b/src/Storage/FileWriteBuffer.h
@@ -0,0 +1,55 @@
+/*
+ * FileWriteBuffer.h
+ *
+ *  Created on: 19 May 2017
+ *      Author: Christian
+ */
+
+#ifndef SRC_STORAGE_FILEWRITEBUFFER_H_
+#define SRC_STORAGE_FILEWRITEBUFFER_H_
+
+#include "RepRapFirmware.h"
+
+#if SAM4E || SAM4S || SAME70
+const size_t NumFileWriteBuffers = 2;					// Number of write buffers
+const size_t FileWriteBufLen = 8192;					// Size of each write buffer
+#else
+const size_t NumFileWriteBuffers = 1;
+const size_t FileWriteBufLen = 4096;
+#endif
+
+// Class to cache data that is about to be written to the SD card. This is NOT a ring buffer,
+// instead it just provides simple interfaces to cache a certain amount of data so that fewer
+// f_write() calls are needed. This effectively improves upload speeds.
+class FileWriteBuffer
+{
+public:
+	FileWriteBuffer(FileWriteBuffer *n) : next(n), index(0) { }
+
+	FileWriteBuffer *Next() const { return next; }
+	void SetNext(FileWriteBuffer *n) { next = n; }
+
+	char *Data() { return reinterpret_cast<char *>(data32); }
+	const char *Data() const { return reinterpret_cast<const char *>(data32); }
+	const size_t BytesStored() const { return index; }
+	const size_t BytesLeft() const { return FileWriteBufLen - index; }
+
+	size_t Store(const char *data, size_t length);			// Stores some data and returns how much could be stored
+	void DataTaken() { index = 0; }							// Called to indicate that the buffer has been written
+
+private:
+	FileWriteBuffer *next;
+
+	size_t index;
+	uint32_t data32[FileWriteBufLen / sizeof(uint32_t)];	// 32-bit aligned buffer for better HSMCI performance
+};
+
+inline size_t FileWriteBuffer::Store(const char *data, size_t length)
+{
+	size_t bytesToStore = min<size_t>(BytesLeft(), length);
+	memcpy(Data() + index, data, bytesToStore);
+	index += bytesToStore;
+	return bytesToStore;
+}
+
+#endif
diff --git a/src/Storage/MassStorage.h b/src/Storage/MassStorage.h
index 25ed0aee..42302f74 100644
--- a/src/Storage/MassStorage.h
+++ b/src/Storage/MassStorage.h
@@ -3,27 +3,30 @@
 
 #include "RepRapFirmware.h"
 #include "Pins.h"
+#include "FileWriteBuffer.h"
 #include "Libraries/Fatfs/ff.h"
+#include "GCodes/GCodeResult.h"
+#include "FileStore.h"
 #include <ctime>
 
 // Info returned by FindFirst/FindNext calls
 struct FileInfo
 {
 	bool isDirectory;
-	char fileName[FILENAME_LENGTH];
-	unsigned long size;
+	char fileName[MaxFilenameLength];
+	uint32_t size;
 	time_t lastModified;
 };
 
 class MassStorage
 {
 public:
-
+	FileStore* OpenFile(const char* directory, const char* fileName, OpenMode mode);
 	bool FindFirst(const char *directory, FileInfo &file_info);
 	bool FindNext(FileInfo &file_info);
 	const char* GetMonthName(const uint8_t month);
 	const char* CombineName(const char* directory, const char* fileName);
-	bool Delete(const char* directory, const char* fileName);
+	bool Delete(const char* directory, const char* fileName, bool silent = false);
 	bool MakeDirectory(const char *parentDir, const char *dirName);
 	bool MakeDirectory(const char *directory);
 	bool Rename(const char *oldFilename, const char *newFilename);
@@ -33,26 +36,66 @@ public:
 	bool DirectoryExists(const char* directory, const char* subDirectory);
 	time_t GetLastModifiedTime(const char* directory, const char *fileName) const;
 	bool SetLastModifiedTime(const char* directory, const char *file, time_t time);
-	bool Mount(size_t card, StringRef& reply, bool reportSuccess);
-	bool Unmount(size_t card, StringRef& reply);
-	bool IsDriveMounted(size_t drive) const { return drive < NumSdCards && isMounted[drive]; }
+	GCodeResult Mount(size_t card, const StringRef& reply, bool reportSuccess);
+	GCodeResult Unmount(size_t card, const StringRef& reply);
+	bool IsDriveMounted(size_t drive) const { return drive < NumSdCards && info[drive].isMounted; }
 	bool CheckDriveMounted(const char* path);
+	bool IsCardDetected(size_t card) const;
+	unsigned int InvalidateFiles(const FATFS *fs, bool doClose);	// Invalidate all open files on the specified file system, returning the number of files invalidated
+	bool AnyFileOpen(const FATFS *fs) const;						// Return true if any files are open on the file system
+	void CloseAllFiles();
+	unsigned int GetNumFreeFiles() const;
+	void Spin();
+
+	enum class InfoResult : uint8_t
+	{
+		badSlot = 0,
+		noCard = 1,
+		ok = 2
+	};
+
+	InfoResult GetCardInfo(size_t slot, uint64_t& capacity, uint64_t& freeSpace, uint32_t& speed, uint32_t& clSize);
 
 friend class Platform;
+friend class FileStore;
 
 protected:
-
 	MassStorage(Platform* p);
 	void Init();
 
+	FileWriteBuffer *AllocateWriteBuffer();
+	void ReleaseWriteBuffer(FileWriteBuffer *buffer);
+
 private:
+	enum class CardDetectState : uint8_t
+	{
+		notPresent = 0,
+		inserting,
+		present,
+		removing
+	};
+
+	struct SdCardInfo
+	{
+		FATFS fileSystem;
+		uint32_t cdChangedTime;
+		uint32_t mountStartTime;
+		Pin cdPin;
+		bool mounting;
+		bool isMounted;
+		CardDetectState cardState;
+	};
+
+	bool InternalUnmount(size_t card, bool doClose);
 	static time_t ConvertTimeStamp(uint16_t fdate, uint16_t ftime);
 
-	Platform* platform;
-	FATFS fileSystems[NumSdCards];
+	SdCardInfo info[NumSdCards];
+
 	DIR findDir;
-	bool isMounted[NumSdCards];
-	char combinedName[FILENAME_LENGTH + 1];
+	char combinedName[MaxFilenameLength + 1];
+	FileWriteBuffer *freeWriteBuffers;
+
+	FileStore files[MAX_FILES];
 };
 
 #endif