diff --git a/recipes/rc2014/sdcard/.gitignore b/recipes/rc2014/sdcard/.gitignore
new file mode 100644
index 0000000..4c1aa4e
--- /dev/null
+++ b/recipes/rc2014/sdcard/.gitignore
@@ -0,0 +1 @@
+cfsin/helo
diff --git a/recipes/rc2014/sdcard/Makefile b/recipes/rc2014/sdcard/Makefile
index 7ebacbc..d408c7e 100644
--- a/recipes/rc2014/sdcard/Makefile
+++ b/recipes/rc2014/sdcard/Makefile
@@ -1,4 +1,4 @@
-TARGETS = os.bin
+TARGETS = os.bin cfsin/helo
 TOOLS = ../../../tools
 ZASM = $(TOOLS)/emul/zasm/zasm
 CFSPACK = $(TOOLS)/cfspack/cfspack
@@ -6,6 +6,7 @@ CFSPACK = $(TOOLS)/cfspack/cfspack
 .PHONY: all
 all: $(TARGETS) sdcard.cfs
 os.bin: glue.asm 
+cfsin/helo: helo.asm
 $(TARGETS):
 	$(ZASM) < $< > $@
 
diff --git a/recipes/rc2014/sdcard/README.md b/recipes/rc2014/sdcard/README.md
index 080f60d..fd07d6c 100644
--- a/recipes/rc2014/sdcard/README.md
+++ b/recipes/rc2014/sdcard/README.md
@@ -98,5 +98,35 @@ you're ready to load your contents with `load d` (load the 13 bytes that you
 wrote to your sd card earlier. You can then `peek d` and see that your
 "Hello World!\n" got loaded in memory!
 
+## Mounting a filesystem from the SD card
+
+The Makefile compiles `helo.asm` in `cfsin` and then packs `cfsin` into a CFS
+filesystem into the `sdcard.cfs` file. That can be mounted by Collapse OS!
+
+    $ cat sdcard.cfs > /dev/sdX
+
+Then, you insert your SD card in your SPI relay and go:
+
+	Collapse OS
+	> mptr 9000
+	9000
+	> sdci
+	> bsel 1
+	> fson
+	> fls
+	helo
+	hello.txt
+	> fopn 0 helo
+	> load 10
+	> peek 10
+	210690C3030048656C6C6F210D0A0000
+	> call 00 0000
+	Hello!
+	>
+
+Now let that sink in for a minute. You've just mounted a filesystem on a SD
+card, loaded a file from it in memory and executed that file, all that on a
+kernel that weights less than 3 kilobytes!
+
 [schematic]: spirelay/spirelay.pdf
 [inspiration]: https://www.ecstaticlyrics.com/electronics/SPI/fast_z80_interface.html
diff --git a/recipes/rc2014/sdcard/glue.asm b/recipes/rc2014/sdcard/glue.asm
index a0a6470..8d613ed 100644
--- a/recipes/rc2014/sdcard/glue.asm
+++ b/recipes/rc2014/sdcard/glue.asm
@@ -5,20 +5,14 @@
 .equ	ACIA_CTL	0x80	; Control and status. RS off.
 .equ	ACIA_IO		0x81	; Transmit. RS on.
 
-jp	init
+jp	init	; 3 bytes
 
-; *** JUMP TABLE ***
-; Why not use this unused space between 0x03 and 0x38 for a jump table?
-	jp	printstr
-	jp	printHex
-	jp	sdcInitialize
-	jp	sdcSendRecv
-	jp	sdcWaitResp
-	jp	sdcCmd
-	jp	sdcCmdR1
-	jp	sdcCmdR7
-	jp	sdcReadBlk
-	jp	sdcSetBlkSize
+; *** Jump Table ***
+jp	printstr
+jp	fsOpen
+jp	fsSeek
+jp	fsTell
+jp	fsGetC
 
 ; interrupt hook
 .fill	0x38-$
@@ -29,21 +23,28 @@ jp	aciaInt
 .equ	ACIA_RAMSTART	RAMSTART
 #include "acia.asm"
 .equ	BLOCKDEV_RAMSTART	ACIA_RAMEND
-.equ	BLOCKDEV_COUNT		2
+.equ	BLOCKDEV_COUNT		3
 #include "blockdev.asm"
 ; List of devices
 .dw	aciaGetC, aciaPutC, 0, 0
-.dw	sdcGetC, 0, 0, 0
+.dw	sdcGetC, 0, sdcSeek, sdcTell
+.dw	blk2GetC, blk2PutC, blk2Seek, blk2Tell
 
 #include "blockdev_cmds.asm"
 
 .equ	STDIO_RAMSTART	BLOCKDEV_RAMEND
 #include "stdio.asm"
 
-.equ	SHELL_RAMSTART		STDIO_RAMEND
-.equ	SHELL_EXTRA_CMD_COUNT	4
+.equ	FS_RAMSTART	STDIO_RAMEND
+.equ	FS_HANDLE_COUNT	1
+#include "fs.asm"
+#include "fs_cmds.asm"
+
+.equ	SHELL_RAMSTART		FS_RAMEND
+.equ	SHELL_EXTRA_CMD_COUNT	8
 #include "shell.asm"
-.dw	sdcInitializeCmd, blkBselCmd, blkSeekCmd, sdcInitializeCmd
+.dw	sdcInitializeCmd, blkBselCmd, blkSeekCmd
+.dw	fsOnCmd, flsCmd, fnewCmd, fdelCmd, fopnCmd
 
 .equ SDC_RAMSTART	SHELL_RAMEND
 .equ SDC_PORT_CSHIGH	6
@@ -67,3 +68,20 @@ init:
 	ei
 	jp	shellLoop
 
+; *** blkdev 2: file handle 0 ***
+
+blk2GetC:
+	ld	de, FS_HANDLES
+	jp	fsGetC
+
+blk2PutC:
+	ld	de, FS_HANDLES
+	jp	fsPutC
+
+blk2Seek:
+	ld	de, FS_HANDLES
+	jp	fsSeek
+
+blk2Tell:
+	ld	de, FS_HANDLES
+	jp	fsTell
diff --git a/recipes/rc2014/sdcard/helo.asm b/recipes/rc2014/sdcard/helo.asm
new file mode 100644
index 0000000..0c905b3
--- /dev/null
+++ b/recipes/rc2014/sdcard/helo.asm
@@ -0,0 +1,10 @@
+; prints "Hello!" on screen
+.equ	printstr	0x03
+
+.org	0x9000
+
+	ld	hl, sHello
+	jp	printstr	; return
+
+sHello:
+	.db	"Hello!", 0x0d, 0x0a, 0