Implemented ~80% of original FAT16. Will work more.

Author: pradosh-arduino

.gitignore

@@ -22,5 +22,4 @@ keys/private_key.pem
 *.bin
 *.raw
 *.so
-*.img
 *.img.tar.gz

Makefile

@@ -61,17 +61,15 @@ QEMU_COMMON = \
     -vga std \
     -debugcon stdio \
     -serial file:serial.log \
-	-boot menu=on \
     -audiodev pa,id=speaker \
     -device rtl8139,netdev=eth0 \
     -netdev user,hostfwd=tcp::5555-:22,id=eth0 \
-    -device usb-ehci,id=ehci \
-    -drive if=none,format=raw,file=$(ISO_FILE),id=usbdisk,index=0\
-    -device usb-storage,drive=usbdisk \
-    -drive if=none,format=raw,file=disk.txtimg,id=disk,index=1 \
+    -cdrom $(ISO_FILE) \
+    -drive if=none,format=raw,file=disk.img,id=disk,index=1 \
     -device ahci,id=ahci \
     -device ide-hd,drive=disk,bus=ahci.0 \
     -rtc base=localtime,clock=host \
+	-boot order=d \
     -m 512
 
 run-x86-hdd:
@@ -115,3 +113,14 @@ fonts:
 clean:
 	@rm -rf ./disk_root $(ISO_FILE) $(ISO_FILE).tar.gz serial.log
 	@cd source && make deep-clean && cd ..
+
+# MISC
+mount-dummy-disk:
+	sudo losetup -fP disk.img
+	sudo mkdir -p /mnt/fat16
+	sudo mount /dev/loop0p1 /mnt/fat16
+	cd /mnt/fat16
+
+umount-dummy-disk:
+	sudo umount /mnt/fat16
+	sudo losetup -d /dev/loop0

disk.txtimg disk.imgdisk.txtimg renamed to disk.img

@@ -68,6 +68,7 @@ typedef struct {
 typedef struct {
     fat16_fs_t* fs;
     fat16_dir_entry_t entry;
+    uint16_t parent_cluster;
     uint32_t pos;
     uint16_t cluster;
 } fat16_file_t;
@@ -94,4 +95,6 @@ void fat16_write_fat_entry(fat16_fs_t* fs, uint16_t cluster, uint16_t value);
 uint16_t fat16_allocate_cluster(fat16_fs_t* fs);
 uint16_t fat16_append_cluster(fat16_fs_t* fs, uint16_t last_cluster);
 void fat16_update_root_entry(fat16_fs_t* fs, fat16_dir_entry_t* entry);
+int fat16_update_dir_entry(fat16_fs_t* fs, uint16_t dir_cluster, fat16_dir_entry_t* entry);
+
 #endif

source/includes/filesystems/fat16.h

@@ -42,7 +42,7 @@ void detect_ahci_devices(ahci_hba_mem_t* ahci_ctrl) {
 
                 handle_sata_disk(i);
 
-                // hcf2();
+                hcf2();
                 break;
             case satapi_disk:
                 printf("[AHCI] SATAPI device detected on port %d", i);

source/kernel/C/ahci.c

@@ -99,8 +99,23 @@ void parse_gpt_partitions(int portno, struct GPT_PartTableHeader* hdr) {
             fat16_fs_t fs;
             fat16_dir_entry_t file;
 
+            //
             fat16_mount(portno, start, &fs);
-            fat16_list_root(&fs);
+            
+            fat16_create(&fs, 0, "FWLOGS.TXT", 0x20);
+            fat16_file_t f;
+            fat16_open(&fs, "/FWLOGS.TXT", &f);
+            const char msg[] = "HELLO FAT16\n";
+            fat16_write(&f, (const uint8_t*)msg, sizeof(msg));
+
+            // rewind
+            f.pos = 0;
+            f.cluster = f.entry.first_cluster;
+            uint8_t buf[64];
+            fat16_read(&f, buf, sizeof(buf));
+            for(int k=0;k<64;k++)
+                printfnoln("%c", buf[k]);
+            print("\n");
         }
     }