diff --git a/kernel/vfs/disk0.asm b/kernel/vfs/disk0.asm
new file mode 100644
index 0000000..5da2ed9
--- /dev/null
+++ b/kernel/vfs/disk0.asm
@@ -0,0 +1,93 @@
+; disk vfs stream routines
+
+disk0_vfs_stream_name: data.strz "disk0"
+
+; open a disk id 0 stream
+; inputs:
+; r2: file struct: pointer to a blank file struct (stream)
+; outputs:
+; r0: non-zero
+open_stream_disk0:
+    push r2
+
+    mov.8 [r2], 0                ; write file_reserved_1
+    inc r2
+    mov.16 [r2], 0               ; write file_reserved_2
+    add r2, 2
+    mov [r2], 0                  ; write file_seek_offset
+    add r2, 4
+    mov.8 [r2], 1                ; write file_system_type
+    inc r2
+    mov [r2], disk0_stream_read  ; write file_read_call
+    add r2, 4
+    mov [r2], disk0_stream_write ; write file_write_call
+    add r2, 4
+    in [r2], 0x80001000          ; write file_size
+    add r2, 4
+    mov [r2], 0                  ; write file_reserved_3
+    add r2, 4
+    mov [r2], 0                  ; write file_reserved_4
+    add r2, 4
+    mov [r2], 0                  ; write file_reserved_5
+
+    pop r2
+    mov r0, 1
+    ret
+
+; read a byte from disk 0
+; inputs:
+; r0: seek offset
+; outputs:
+; r0: byte
+disk0_stream_read:
+    push r1
+    push r2
+
+    push r0
+    div r0, 512
+    mov r1, 0
+    mov r2, TEMP_SECTOR_BUF
+    call read_sector
+    pop r0
+    rem r0, 512
+    add r0, TEMP_SECTOR_BUF
+    movz.8 r0, [r0]
+
+    pop r2
+    pop r1
+    ret
+
+; write a byte to disk 0
+; inputs:
+; r0: pointer to source buffer
+; r1: seek offset
+; outputs:
+; none
+disk0_stream_write:
+    push r0
+    push r1
+    push r2
+
+    push r0
+    push r1
+    div r1, 512
+    mov r0, r1
+    mov r1, 0
+    mov r2, TEMP_SECTOR_BUF
+    call read_sector
+    pop r1
+    pop r0
+    push r1
+    rem r1, 512
+    add r1, TEMP_SECTOR_BUF
+    mov.8 [r1], [r0]
+    pop r0
+    div r0, 512
+    mov r1, 0
+    mov r2, TEMP_SECTOR_BUF
+    call write_sector
+
+    pop r2
+    pop r1
+    pop r0
+    ret
diff --git a/kernel/vfs/disk1.asm b/kernel/vfs/disk1.asm
new file mode 100644
index 0000000..c66a0db
--- /dev/null
+++ b/kernel/vfs/disk1.asm
@@ -0,0 +1,93 @@
+; disk vfs stream routines
+
+disk1_vfs_stream_name: data.strz "disk1"
+
+; open a disk id 1 stream
+; inputs:
+; r2: file struct: pointer to a blank file struct (stream)
+; outputs:
+; r0: non-zero
+open_stream_disk1:
+    push r2
+
+    mov.8 [r2], 0                ; write file_reserved_1
+    inc r2
+    mov.16 [r2], 0               ; write file_reserved_2
+    add r2, 2
+    mov [r2], 0                  ; write file_seek_offset
+    add r2, 4
+    mov.8 [r2], 1                ; write file_system_type
+    inc r2
+    mov [r2], disk1_stream_read  ; write file_read_call
+    add r2, 4
+    mov [r2], disk1_stream_write ; write file_write_call
+    add r2, 4
+    in [r2], 0x80001001          ; write file_size
+    add r2, 4
+    mov [r2], 0                  ; write file_reserved_3
+    add r2, 4
+    mov [r2], 0                  ; write file_reserved_4
+    add r2, 4
+    mov [r2], 0                  ; write file_reserved_5
+
+    pop r2
+    mov r0, 1
+    ret
+
+; read a byte from disk 1
+; inputs:
+; r0: seek offset
+; outputs:
+; r0: byte
+disk1_stream_read:
+    push r1
+    push r2
+
+    push r0
+    div r0, 512
+    mov r1, 1
+    mov r2, TEMP_SECTOR_BUF
+    call read_sector
+    pop r0
+    rem r0, 512
+    add r0, TEMP_SECTOR_BUF
+    movz.8 r0, [r0]
+
+    pop r2
+    pop r1
+    ret
+
+; write a byte to disk 1
+; inputs:
+; r0: pointer to source buffer
+; r1: seek offset
+; outputs:
+; none
+disk1_stream_write:
+    push r0
+    push r1
+    push r2
+
+    push r0
+    push r1
+    div r1, 512
+    mov r0, r1
+    mov r1, 1
+    mov r2, TEMP_SECTOR_BUF
+    call read_sector
+    pop r1
+    pop r0
+    push r1
+    rem r1, 512
+    add r1, TEMP_SECTOR_BUF
+    mov.8 [r1], [r0]
+    pop r0
+    div r0, 512
+    mov r1, 1
+    mov r2, TEMP_SECTOR_BUF
+    call write_sector
+
+    pop r2
+    pop r1
+    pop r0
+    ret
diff --git a/kernel/vfs/disk2.asm b/kernel/vfs/disk2.asm
new file mode 100644
index 0000000..873fa24
--- /dev/null
+++ b/kernel/vfs/disk2.asm
@@ -0,0 +1,93 @@
+; disk vfs stream routines
+
+disk2_vfs_stream_name: data.strz "disk2"
+
+; open a disk id 2 stream
+; inputs:
+; r2: file struct: pointer to a blank file struct (stream)
+; outputs:
+; r0: non-zero
+open_stream_disk2:
+    push r2
+
+    mov.8 [r2], 0                ; write file_reserved_1
+    inc r2
+    mov.16 [r2], 0               ; write file_reserved_2
+    add r2, 2
+    mov [r2], 0                  ; write file_seek_offset
+    add r2, 4
+    mov.8 [r2], 1                ; write file_system_type
+    inc r2
+    mov [r2], disk2_stream_read  ; write file_read_call
+    add r2, 4
+    mov [r2], disk2_stream_write ; write file_write_call
+    add r2, 4
+    in [r2], 0x80001002          ; write file_size
+    add r2, 4
+    mov [r2], 0                  ; write file_reserved_3
+    add r2, 4
+    mov [r2], 0                  ; write file_reserved_4
+    add r2, 4
+    mov [r2], 0                  ; write file_reserved_5
+
+    pop r2
+    mov r0, 1
+    ret
+
+; read a byte from disk 2
+; inputs:
+; r0: seek offset
+; outputs:
+; r0: byte
+disk2_stream_read:
+    push r1
+    push r2
+
+    push r0
+    div r0, 512
+    mov r1, 2
+    mov r2, TEMP_SECTOR_BUF
+    call read_sector
+    pop r0
+    rem r0, 512
+    add r0, TEMP_SECTOR_BUF
+    movz.8 r0, [r0]
+
+    pop r2
+    pop r1
+    ret
+
+; write a byte to disk 2
+; inputs:
+; r0: pointer to source buffer
+; r1: seek offset
+; outputs:
+; none
+disk2_stream_write:
+    push r0
+    push r1
+    push r2
+
+    push r0
+    push r1
+    div r1, 512
+    mov r0, r1
+    mov r1, 2
+    mov r2, TEMP_SECTOR_BUF
+    call read_sector
+    pop r1
+    pop r0
+    push r1
+    rem r1, 512
+    add r1, TEMP_SECTOR_BUF
+    mov.8 [r1], [r0]
+    pop r0
+    div r0, 512
+    mov r1, 2
+    mov r2, TEMP_SECTOR_BUF
+    call write_sector
+
+    pop r2
+    pop r1
+    pop r0
+    ret
diff --git a/kernel/vfs/disk3.asm b/kernel/vfs/disk3.asm
new file mode 100644
index 0000000..8e81780
--- /dev/null
+++ b/kernel/vfs/disk3.asm
@@ -0,0 +1,93 @@
+; disk vfs stream routines
+
+disk3_vfs_stream_name: data.strz "disk3"
+
+; open a disk id 3 stream
+; inputs:
+; r2: file struct: pointer to a blank file struct (stream)
+; outputs:
+; r0: non-zero
+open_stream_disk3:
+    push r2
+
+    mov.8 [r2], 0                ; write file_reserved_1
+    inc r2
+    mov.16 [r2], 0               ; write file_reserved_2
+    add r2, 2
+    mov [r2], 0                  ; write file_seek_offset
+    add r2, 4
+    mov.8 [r2], 1                ; write file_system_type
+    inc r2
+    mov [r2], disk3_stream_read  ; write file_read_call
+    add r2, 4
+    mov [r2], disk3_stream_write ; write file_write_call
+    add r2, 4
+    in [r2], 0x80001003          ; write file_size
+    add r2, 4
+    mov [r2], 0                  ; write file_reserved_3
+    add r2, 4
+    mov [r2], 0                  ; write file_reserved_4
+    add r2, 4
+    mov [r2], 0                  ; write file_reserved_5
+
+    pop r2
+    mov r0, 1
+    ret
+
+; read a byte from disk 3
+; inputs:
+; r0: seek offset
+; outputs:
+; r0: byte
+disk3_stream_read:
+    push r1
+    push r2
+
+    push r0
+    div r0, 512
+    mov r1, 3
+    mov r2, TEMP_SECTOR_BUF
+    call read_sector
+    pop r0
+    rem r0, 512
+    add r0, TEMP_SECTOR_BUF
+    movz.8 r0, [r0]
+
+    pop r2
+    pop r1
+    ret
+
+; write a byte to disk 3
+; inputs:
+; r0: pointer to source buffer
+; r1: seek offset
+; outputs:
+; none
+disk3_stream_write:
+    push r0
+    push r1
+    push r2
+
+    push r0
+    push r1
+    div r1, 512
+    mov r0, r1
+    mov r1, 3
+    mov r2, TEMP_SECTOR_BUF
+    call read_sector
+    pop r1
+    pop r0
+    push r1
+    rem r1, 512
+    add r1, TEMP_SECTOR_BUF
+    mov.8 [r1], [r0]
+    pop r0
+    div r0, 512
+    mov r1, 3
+    mov r2, TEMP_SECTOR_BUF
+    call write_sector
+
+    pop r2
+    pop r1
+    pop r0
+    ret
diff --git a/kernel/vfs/ofb.asm b/kernel/vfs/ofb.asm
new file mode 100644
index 0000000..90b1531
--- /dev/null
+++ b/kernel/vfs/ofb.asm
@@ -0,0 +1,132 @@
+; overlay framebuffer vfs stream routines
+
+overlay_vfs_stream_name: data.strz "ofb"
+
+; open an overlay framebuffer stream
+; inputs:
+; r0: pointer to null-terminated string "ofbXX" where XX is 0 - 31
+; r2: file struct: pointer to a blank file struct (stream)
+; outputs:
+; r0: non-zero
+open_stream_ofb:
+    push r1
+    push r2
+
+    add r0, 3
+    mov r1, 10
+    call string_to_int
+
+    mov.8 [r2], r0             ; write file_overlay
+    inc r2
+    mov.16 [r2], 0             ; write file_reserved_2
+    add r2, 2
+    mov [r2], 0                ; write file_seek_offset
+    add r2, 4
+    mov.8 [r2], 1              ; write file_system_type
+    inc r2
+    mov [r2], ofb_stream_read  ; write file_read_call
+    add r2, 4
+    mov [r2], ofb_stream_write ; write file_write_call
+    add r2, 4
+    or r0, 0x80000100
+    in r0, r0
+    mov r1, r0
+    srl r1, 16
+    mul r1, r0
+    mov [r2], r1               ; write file_size
+    add r2, 4
+    mov [r2], 0                ; write file_reserved_3
+    add r2, 4
+    mov [r2], 0                ; write file_reserved_4
+    add r2, 4
+    mov [r2], 0                ; write file_reserved_5
+
+    pop r2
+    pop r1
+    mov r0, 1
+    ret
+
+; read a byte from an overlay framebuffer
+; inputs:
+; r0: seek offset
+; r1: pointer to file struct + 8
+; outputs:
+; r0: byte
+ofb_stream_read:
+    push r1
+    push r2
+
+    ; get overlay framebuffer pointer in r2
+    sub r1, 8 ; point to file_overlay (file_reserved_1)
+    movz.8 r1, [r1]
+    or r1, 0x80000200
+    in r2, r1
+
+    ; get overlay size in r1
+    sub r1, 0x100
+    in r1, r1
+    push r0
+    mov r0, r1
+    srl r0, 16
+    and r1, 0x0000FFFF
+    mul r1, r0
+    mul r0, 4
+    pop r0
+
+    ; ensure the seek offset is less than the overlay size
+    cmp r0, r1
+    ifgteq mov r0, r1
+    ifgteq dec r0
+
+    ; fetch the byte
+    add r0, r2
+    movz.8 r0, [r0]
+
+    pop r2
+    pop r1
+    ret
+
+; write a byte to an overlay framebuffer
+; inputs:
+; r0: pointer to source buffer
+; r1: seek offset
+; r3: pointer to file struct + 12
+; outputs:
+; none
+ofb_stream_write:
+    push r1
+    push r2
+    push r3
+    push r4
+
+    ; get overlay framebuffer pointer in r2
+    sub r3, 12 ; point to file_overlay (file_reserved_1)
+    movz.8 r3, [r3]
+    or r3, 0x80000200
+    in r2, r3
+
+    ; get overlay size in r4
+    sub r3, 0x100
+    in r4, r3
+    push r0
+    mov r0, r4
+    srl r0, 16
+    and r4, 0x0000FFFF
+    mul r4, r0
+    mul r4, 4
+    pop r0
+
+    ; ensure the seek offset is less than the overlay size
+    cmp r1, r4
+    ifgteq mov r1, r4
+    ifgteq dec r1
+
+    ; write the byte
+    add r2, r1
+    mov.8 [r2], [r0]
+
+    pop r4
+    pop r3
+    pop r2
+    pop r1
+    ret
diff --git a/kernel/vfs/romdisk.asm b/kernel/vfs/romdisk.asm
new file mode 100644
index 0000000..c577b8f
--- /dev/null
+++ b/kernel/vfs/romdisk.asm
@@ -0,0 +1,67 @@
+; disk vfs stream routines
+
+romdisk_vfs_stream_name: data.strz "romdisk"
+
+; open a disk id 4 stream
+; inputs:
+; r2: file struct: pointer to a blank file struct (stream)
+; outputs:
+; r0: non-zero
+open_stream_romdisk:
+    push r2
+
+    mov.8 [r2], 0                  ; write file_reserved_1
+    inc r2
+    mov.16 [r2], 0                 ; write file_reserved_2
+    add r2, 2
+    mov [r2], 0                    ; write file_seek_offset
+    add r2, 4
+    mov.8 [r2], 1                  ; write file_system_type
+    inc r2
+    mov [r2], romdisk_stream_read  ; write file_read_call
+    add r2, 4
+    mov [r2], romdisk_stream_write ; write file_write_call
+    add r2, 4
+    mov [r2], 65536                ; write file_size
+    add r2, 4
+    mov [r2], 0                    ; write file_reserved_3
+    add r2, 4
+    mov [r2], 0                    ; write file_reserved_4
+    add r2, 4
+    mov [r2], 0                    ; write file_reserved_5
+
+    pop r2
+    mov r0, 1
+    ret
+
+; read a byte from disk 4
+; inputs:
+; r0: seek offset
+; outputs:
+; r0: byte
+romdisk_stream_read:
+    push r1
+    push r2
+
+    push r0
+    div r0, 512
+    mov r1, 4
+    mov r2, TEMP_SECTOR_BUF
+    call read_sector
+    pop r0
+    rem r0, 512
+    add r0, TEMP_SECTOR_BUF
+    movz.8 r0, [r0]
+
+    pop r2
+    pop r1
+    ret
+
+; write a byte to disk 4
+; inputs:
+; r0: pointer to source buffer
+; r1: seek offset
+; outputs:
+; none
+romdisk_stream_write:
+    ret
diff --git a/kernel/vfs/vfs.asm b/kernel/vfs/vfs.asm
index 664c62b..dfb65fc 100644
--- a/kernel/vfs/vfs.asm
+++ b/kernel/vfs/vfs.asm
@@ -1,5 +1,7 @@
 ; virtual filesystem routines
 
+const TEMP_SECTOR_BUF: 0x01FFF808
+
 ; file struct for file:
 ;   file_disk:         1 byte
 ;   file_first_sector: 2 bytes
@@ -44,12 +46,51 @@ open_stream:
 
     inc r0
 
+    ; disk0
+    mov r1, disk0_vfs_stream_name
+    call compare_string
+    ifz pop r1
+    ifz jmp open_stream_disk0
+
+    ; disk1
+    mov r1, disk1_vfs_stream_name
+    call compare_string
+    ifz pop r1
+    ifz jmp open_stream_disk1
+
+    ; disk2
+    mov r1, disk2_vfs_stream_name
+    call compare_string
+    ifz pop r1
+    ifz jmp open_stream_disk2
+
+    ; disk3
+    mov r1, disk3_vfs_stream_name
+    call compare_string
+    ifz pop r1
+    ifz jmp open_stream_disk3
+
     ; fb
     mov r1, framebuffer_vfs_stream_name
     call compare_string
     ifz pop r1
     ifz jmp open_stream_fb
 
+    ; ofb0 - ofb31
+    push r2
+    mov r1, overlay_vfs_stream_name
+    mov r2, 3
+    call compare_memory_bytes
+    pop r2
+    ifz pop r1
+    ifz jmp open_stream_ofb
+
+    ; romdisk
+    mov r1, romdisk_vfs_stream_name
+    call compare_string
+    ifz pop r1
+    ifz jmp open_stream_romdisk
+
     ; serial
     mov r1, serial_vfs_stream_name
     call compare_string
@@ -130,11 +171,7 @@ stream_read:
 stream_read_loop:
     call stream_read_char
 
-    push r0
-    push r2
-    call yield_task
-    pop r2
-    pop r0
+    call save_state_and_yield_task
 
     inc r2
     dec r0
@@ -150,9 +187,9 @@ stream_read_char:
     push r2
 
     ; call [file_read_call] with seek offset in r0
-    add r1, 2
+    add r1, 3
     mov r0, [r1]
-    add r1, 6
+    add r1, 5
     call [r1]
 
     ; put the result into [r2]
@@ -160,7 +197,7 @@ stream_read_char:
     mov.8 [r2], r0
 
     ; increment the seek offset
-    sub r1, 6
+    sub r1, 5
     inc [r1]
 
     pop r1
@@ -208,14 +245,14 @@ stream_write_char:
 
     ; call [file_write_call] with pointer to src buf in r0 and seek offset in r1
     mov r3, r1
-    add r3, 2
+    add r3, 3
     mov r0, r2
     mov r1, [r3]
-    add r3, 10
+    add r3, 9
     call [r3]
 
     ; increment the seek offset
-    sub r3, 10
+    sub r3, 9
     inc [r3]
 
     pop r3
@@ -307,5 +344,11 @@ convert_filename_fail:
 convert_filename_output_string: data.fill 0, 12
 
     ; named streams
+    #include "vfs/disk0.asm"
+    #include "vfs/disk1.asm"
+    #include "vfs/disk2.asm"
+    #include "vfs/disk3.asm"
     #include "vfs/fb.asm"
+    #include "vfs/ofb.asm"
+    #include "vfs/romdisk.asm"
     #include "vfs/serial.asm"