Initial commit - forked from Expos

Author: vivekzhere

.gitignore

@@ -0,0 +1 @@
+*~

FileSystemCode/Makefile

@@ -0,0 +1,10 @@
+DISK = disk
+
+all: fileSystem
+
+fileSystem: fileSystem.h fileSystem.c fileUtility.h fileUtility.h interface.h interface.c createDisk.h createDisk.c
+	gcc fileSystem.c fileUtility.c interface.c createDisk.c -o fileSystem
+	cp -f fileSystem ../
+
+clean:
+	rm -rf $(DISK) *.o fileSystem 2> /dev/null

FileSystemCode/README

@@ -0,0 +1,19 @@
+Compiler: gcc 4.4.3(recomended)
+Platform: Linux 2.6(recomended)
+
+NOTE:
+  1. The disk file is named as "disk". To change it make changes in:
+					    a) First line of the Makefile
+					    b) DISK_NAME constant in fileSystem.h
+  
+  2. The entire code works by fist writing to a memory copy before committing to the actual disk file.
+
+Compiling: 
+  1. cd to directory.
+  2. Type 'make' and press enter.
+
+Run:
+  1. Compile by following the above steps.
+  2. Run ./fileSystem on the terminal.
+  3. Follow the menu.
+  

FileSystemCode/ToDo

@@ -0,0 +1,6 @@
+Things to do
+1. Add -1 as basic block entry for empty entries in spec.
+2. Interface for data blocks if required.
+4. New line problem in file name. Copying the code from disk to memory appends a new line to the end of everyline. So the data section
+  contains the string with a newline. This can cause problems when comparing with strings read from terminal. This was avoided temporarily
+  by appending a newline to the string read using SIN in the machine.

FileSystemCode/createDisk.c

@@ -0,0 +1,54 @@
+#include "createDisk.h"
+
+
+/*
+  createDisk creates  the disk file if not present.
+  if format is equal to zero then the function creates the disk but does not format it.
+  if format is not equal to zero then the function will create and format the disk.
+  Formatting is done as follows:
+    1. A memory copy of the disk is maintained. This copy contains NO_BLOCKS_TO_COPY + EXTRA_BLOCKS (in this case 13 + 1) blocks.
+      The extra block is a temporary block. This memory copy is called the virtual disk. This is first cleared.
+    2. Then the memory freelist is initialised.
+    3. The fat blocks are also initialised. The basic block entries are all set to -1. The memory copy is then committed to the 
+      disk file.
+    4. Finally the entry for init process is made.
+*/
+void createDisk(int format){
+    int fd;
+      if(format){
+	 fd = open(DISK_NAME, O_CREAT | O_TRUNC | O_SYNC, 0666);
+	 clearVirtDisk();
+	 close(fd);
+	// loadFileToVirtualDisk();		note: commented this line
+	 int i=0,j=0;
+	 for(j=0; j<NO_OF_FREE_LIST_BLOCKS; j++){
+		if(j == 0)
+		  for(i=0;i<DATA_START_BLOCK + INIT_SIZE ;i++)
+		      storeInteger(disk[FREE_LIST_START_BLOCK].word[i], 1);
+		else
+			i=0;
+		
+		for( ;i<BLOCK_SIZE;i++)
+			storeInteger(disk[FREE_LIST_START_BLOCK + j].word[i], 0);
+		writeToDisk(FREE_LIST_START_BLOCK + j, FREE_LIST_START_BLOCK+j);
+	    }
+	    
+	    
+	for(j=0; j<NO_OF_FAT_BLOCKS; j++){
+		for(i=FAT_BASICBLOCK; i<BLOCK_SIZE; i=i+FAT_ENTRY_SIZE){
+			storeInteger(disk[FAT_START_BLOCK + j].word[i], -1);
+		}
+		writeToDisk(FAT_START_BLOCK+j, FAT_START_BLOCK+j);
+	}
+	
+	initializeINIT();
+      }
+      else
+      {
+	fd = open(DISK_NAME, O_CREAT, 0666);
+	close(fd);
+      }
+	
+}
+
+

FileSystemCode/createDisk.h

@@ -0,0 +1,16 @@
+#ifndef CREATEDISK_H
+#define CREATEDISK_H
+
+#include <stdio.h>
+#include "fileSystem.h"
+#include <string.h>
+#include "fileUtility.h"
+#include <fcntl.h>
+
+
+/*
+  This function creates the disk file if not present. It also has an option for formatting or not.
+*/
+void createDisk(int format);
+
+#endif

FileSystemCode/disk.h

@@ -0,0 +1,2 @@
+#define DISK_NAME 	"disk"
+#define BOOT_BLOCK	0