diff --git a/tasks/mm0/include/init.h b/tasks/mm0/include/init.h
index 4a5d6e3..f91e070 100644
--- a/tasks/mm0/include/init.h
+++ b/tasks/mm0/include/init.h
@@ -1,9 +1,30 @@
 /*
+ * Data that comes from the kernel, and other init data.
+ *
  * Copyright (C) 2007 Bahadir Balban
  */
-#ifndef __INIT_H__
-#define __INIT_H__
+#ifndef __MM_INIT_H__
+#define __MM_INIT_H__
+
+#include <l4/macros.h>
+#include <l4/config.h>
+#include <l4/types.h>
+#include <l4/generic/physmem.h>
+#include INC_PLAT(offsets.h)
+#include INC_GLUE(memory.h)
+#include INC_GLUE(memlayout.h)
+#include INC_ARCH(bootdesc.h)
+#include <vm_area.h>
+
+struct initdata {
+	struct bootdesc *bootdesc;
+	struct page_bitmap page_map;
+};
+
+extern struct initdata initdata;
+
+int request_initdata(struct initdata *i);
 
 void initialise(void);
 
-#endif /* __INIT_H__ */
+#endif /* __MM_INIT_H__ */
diff --git a/tasks/mm0/include/kdata.h b/tasks/mm0/include/kdata.h
deleted file mode 100644
index d2fbbee..0000000
--- a/tasks/mm0/include/kdata.h
+++ /dev/null
@@ -1,29 +0,0 @@
-/*
- * Data that comes from the kernel.
- *
- * Copyright (C) 2007 Bahadir Balban
- */
-#ifndef __MM_KDATA_H__
-#define __MM_KDATA_H__
-
-#include <l4/macros.h>
-#include <l4/config.h>
-#include <l4/types.h>
-#include <l4/generic/physmem.h>
-#include INC_PLAT(offsets.h)
-#include INC_GLUE(memory.h)
-#include INC_GLUE(memlayout.h)
-#include INC_ARCH(bootdesc.h)
-#include <vm_area.h>
-
-struct initdata {
-	struct bootdesc *bootdesc;
-	struct list_head boot_file_list;
-	struct page_bitmap page_map;
-};
-
-extern struct initdata initdata;
-
-int request_initdata(struct initdata *i);
-
-#endif /* __MM_KDATA_H__ */
diff --git a/tasks/mm0/include/proc.h b/tasks/mm0/include/proc.h
index 1c8d159..24241bb 100644
--- a/tasks/mm0/include/proc.h
+++ b/tasks/mm0/include/proc.h
@@ -3,11 +3,11 @@
 
 #include <vm_area.h>
 
-struct proc_files {
-	struct vm_object *stack_file;	/* ZI, RO: devzero, RW: private */
-	struct vm_object *env_file;	/* NON-ZI, RO: private, RW: private */
-	struct vm_object *data_file;	/* NON-ZI, RO: shared,  RW: private */
-	struct vm_object *bss_file;	/* ZI, RO: devzero, RW: private */
+struct proc_vm_objects {
+	struct vm_object *stack;	/* ZI, RO: devzero, RW: private */
+	struct vm_object *env;		/* NON-ZI, RO: private, RW: private */
+	struct vm_object *data;		/* NON-ZI, RO: shared,  RW: private */
+	struct vm_object *bss;		/* ZI, RO: devzero, RW: private */
 };
 
 int task_setup_vm_objects(struct tcb *t);
diff --git a/tasks/mm0/include/vm_area.h b/tasks/mm0/include/vm_area.h
index e4ee8a9..ea3df2d 100644
--- a/tasks/mm0/include/vm_area.h
+++ b/tasks/mm0/include/vm_area.h
@@ -1,5 +1,5 @@
 /*
- * Virtual memory area descriptors. No page cache yet.
+ * Virtual memory area descriptors.
  *
  * Copyright (C) 2007 Bahadir Balban
  */
@@ -20,17 +20,17 @@
 #define VM_WRITE			(1 << 2)
 #define VM_EXEC				(1 << 3)
 #define VM_PROT_MASK			(VM_READ | VM_WRITE | VM_EXEC)
-#define VM_SWAPPED			(1 << 4)
 
-/* VMA flags */
+/* Shared copy of a file */
 #define VMA_SHARED			(1 << 3)
-/* VMA that's not file-backed, always ZI */
-#define VMA_ANON			(1 << 4)
-/* Private copy of a file VMA, can be ZI */
-#define VMA_COW				(1 << 5)
-
-/* VMA object type flags */
-#define VMOBJ_SHADOW			(1 << 6)
+/* VMA that's not file-backed, always maps devzero as VMA_COW */
+#define VMA_ANONYMOUS			(1 << 4)
+/* Private copy of a file */
+#define VMA_PRIVATE			(1 << 5)
+/* Copy-on-write semantics */
+#define VMA_COW				(1 << 6)
+/* A vm object that is a shadow of another */
+#define VMOBJ_SHADOW			(1 << 7)
 
 struct page {
 	int count;		/* Refcount */
@@ -69,6 +69,16 @@ struct vm_pager {
 	struct vm_pager_ops ops;	/* The ops the pager does on area */
 };
 
+enum VM_OBJ_TYPE {
+	VM_OBJ_SHADOW = 1,	/* Anonymous pages, swap_pager, no vm_file */
+	VM_OBJ_VNODE,		/* VFS file pages, vnode_pager, has vm_file */
+	VM_OBJ_DEVICE		/* Device pages, device_pager, has vm_file */
+};
+
+/* TODO:
+ * How to distinguish different devices handling page faults ???
+ */
+
 /*
  * Describes the in-memory representation of a resource. This could
  * point at a file or another resource, e.g. a device area, swapper space,
@@ -81,20 +91,19 @@ struct vm_object {
 	int vma_refcnt;		    /* Number of vmas that refer */
 	int shadow_refcnt;	    /* Number of shadows that refer */
 	struct list_head shadows;   /* List of vm objects that shadow this one */
-	struct vm_object *orig_vma; /* Original object that this one shadows */
+	struct vm_object *orig_obj; /* Original object that this one shadows */
 	unsigned int type;	    /* Defines the type of the object */
 	struct list_head list;	    /* List of all vm objects in memory */
-	struct list_head page_cache;/* List of in-memory pages */
-	struct vm_pager *pager;		  /* The pager for this object */
-	union private_data {		  /* Private data about the object */
-		struct vm_file *file;	  /* VFS file-specific information */
-	} priv;
+	struct list_head page_cache;	/* List of in-memory pages */
+	struct vm_pager *pager;		/* The pager for this object */
 };
 
-/* In memory representation of a vfs file. */
+/* In memory representation of either a vfs file, a device. */
 struct vm_file {
 	unsigned long vnum;
 	unsigned long length;
+	struct vm_object vm_obj;
+	void *priv_data;	/* Device pagers use to access device info */
 };
 
 /* To create per-vma vm_object lists */
diff --git a/tasks/mm0/src/boot.c b/tasks/mm0/src/boot.c
new file mode 100644
index 0000000..8aa353e
--- /dev/null
+++ b/tasks/mm0/src/boot.c
@@ -0,0 +1,58 @@
+
+#define vm_object_to_file(obj)	\
+	(struct vm_file *)container_of(obj, struct vm_file, vm_obj)
+
+/* Returns the page with given offset in this vm_object */
+struct page *devzero_pager_page_in(struct vm_object *vm_obj,
+				   unsigned long page_offset)
+{
+	struct vm_file *devzero = container_of(vm_obj, struct vm_file, vm_obj);
+	struct page *zpage = devzero->priv_data;
+
+	/* Update zero page struct. */
+	spin_lock(&page->lock);
+	zpage->count++;
+	spin_unlock(&page->lock);
+
+	return zpage;
+}
+
+struct page *device_page_in(struct vm_object *vm_obj,
+			    unsigned long page_offset)
+{
+	struct vm_file *dev_file;
+
+	BUG_ON(vm_obj->type != VM_OBJ_DEVICE);
+	dev_file = vm_object_to_file(vm_obj);
+
+}
+
+struct vm_pager device_pager {
+	.page_in = device_page_in,
+};
+LIST_HEAD(&boot_files);
+
+/* From bare boot images, create mappable device files */
+int init_boot_files(struct initdata *initdata)
+{
+	int err;
+	struct svc_image *img;
+	unsigned int sp, pc;
+	struct tcb *task;
+	struct task_ids ids;
+	struct bootdesc *bd;
+	struct vm_file *boot_file;
+
+	bd = initdata->bootdesc;
+
+	for (int i = 0; i < bd->total_images; i++) {
+		img = &bd->images[i];
+		boot_file = kzalloc(sizeof(struct vm_file));
+		INIT_LIST_HEAD(&boot_file->vm_obj.list);
+		boot_file->priv_data = img;
+		boot_file->length = img->phys_end - img->phys_start;
+		boot_file->pager = &device_pager;
+		list_add(&boot_file->vm_obj.list, &boot_files);
+	}
+}
+
diff --git a/tasks/mm0/src/devzero.c b/tasks/mm0/src/devzero.c
deleted file mode 100644
index fba0514..0000000
--- a/tasks/mm0/src/devzero.c
+++ /dev/null
@@ -1,65 +0,0 @@
-/*
- * Handling of the special zero page.
- *
- * Copyright (C) 2007 Bahadir Balban
- */
-#include <memory.h>
-#include <mm/alloc_page.h>
-#include <l4lib/arch/syscalls.h>
-#include <l4lib/arch/syslib.h>
-#include <string.h>
-#include INC_GLUE(memory.h)
-#include INC_SUBARCH(mm.h)
-#include <l4/generic/space.h>
-#include <arch/mm.h>
-
-static void *zpage_p;
-static struct page *zpage;
-static struct vm_file devzero;
-
-void init_zero_page(void)
-{
-	void *zpage_v;
-	zpage_p = alloc_page(1);
-	zpage = phys_to_page(zpage_p);
-
-	/* Map it to self */
-	zpage_v = l4_map_helper(zpage_p, 1);
-
-	/* Zero it */
-	memset(zpage_v, 0, PAGE_SIZE);
-
-	/* Unmap it */
-	l4_unmap_helper(zpage_v, 1);
-
-	/* Update page struct. All other fields are zero */
-	zpage->count++;
-}
-
-void init_devzero(void)
-{
-	init_zero_page();
-
-	INIT_LIST_HEAD(&devzero.list);
-	INIT_LIST_HEAD(&devzero.page_cache_list);
-	devzero.length = (unsigned int)-1;
-	devzero.vnum = -1;
-}
-
-struct vm_file *get_devzero(void)
-{
-	return &devzero;
-}
-
-void *get_zero_page(void)
-{
-	zpage->count++;
-	return zpage_p;
-}
-
-void put_zero_page(void)
-{
-	zpage->count--;
-	BUG_ON(zpage->count < 0);
-}
-
diff --git a/tasks/mm0/src/mmap.c b/tasks/mm0/src/mmap.c
index 5f56ce5..b5d5432 100644
--- a/tasks/mm0/src/mmap.c
+++ b/tasks/mm0/src/mmap.c
@@ -12,10 +12,6 @@
 #include <memory.h>
 #include <l4lib/arch/syscalls.h>
 
-/* Swap related bookkeeping.
-static struct vm_file shm_swap_file;
-static struct id_pool *swap_file_offset_pool;
-*/
 
 /* TODO: This is to be implemented when fs0 is ready. */
 int do_msync(void *addr, unsigned long size, unsigned int flags, struct tcb *task)
@@ -237,20 +233,6 @@ struct vm_area *vma_split(struct vm_area *vma, struct tcb *task,
 	return new;
 }
 
-/*
- * For written anonymous regions swapfile segments are allocated dynamically.
- * when vma regions are modified these allocations must be re-adjusted.
- * This call handles this adjustment as well as the vma.
- */
-int vma_swapfile_realloc(struct vm_area *vma, unsigned long pfn_start,
-			 unsigned long pfn_end)
-{
-	/* TODO: Reslot in swapfile */
-	BUG();
-	return 0;
-}
-
-
 /* This shrinks the vma from *one* end only, either start or end */
 int vma_shrink(struct vm_area *vma, struct tcb *task, unsigned long pfn_start,
 	       unsigned long pfn_end)
@@ -407,12 +389,12 @@ is_vma_mergeable(unsigned long pfn_start, unsigned long pfn_end,
  * existing vma and the flags match, it returns the adjacent vma. Otherwise it
  * returns 0.
  */
-int find_unmapped_area(struct vm_area **existing, struct vm_file *file,
-		       unsigned long pfn_start, unsigned long npages,
-		       unsigned int flags, struct list_head *vm_area_head)
+int find_unmapped_area(struct vm_area **existing,  unsigned long pfn_start,
+		       unsigned long npages, unsigned int flags,
+		       struct list_head *vm_area_head)
 {
-	struct vm_area *vma;
 	unsigned long pfn_end = pfn_start + npages;
+	struct vm_area *vma;
 	*existing = 0;
 
 	list_for_each_entry(vma, vm_area_head, list) {
@@ -445,26 +427,33 @@ int do_mmap(struct vm_file *mapfile, unsigned long f_offset, struct tcb *t,
 	    unsigned long map_address, unsigned int flags, unsigned int pages)
 {
 	struct vm_area *vma;
+	struct vm_object *vmobj;
 	unsigned long pfn_start = __pfn(map_address);
 
 	if (!mapfile) {
 	       if (flags & VMA_ANON) {
-			mapfile = get_devzero();
+			vmobj = get_devzero();
 			f_offset = 0;
 	       } else
 			BUG();
-	} else if (pages > (__pfn(page_align_up(mapfile->length)) - f_offset)) {
-		printf("%s: Trying to map %d pages from page %d, "
-		       "but file length is %d\n", __FUNCTION__, pages,
-		       f_offset, __pfn(page_align_up(mapfile->length)));
-		return -EINVAL;
+	} else {
+		if (pages > (__pfn(page_align_up(mapfile->length))
+			     - f_offset)) {
+			printf("%s: Trying to map %d pages from page %d, "
+			       "but file length is %d\n", __FUNCTION__, pages,
+			       f_offset, __pfn(page_align_up(mapfile->length)));
+			return -EINVAL;
+		}
+		/* Set up a vm object for given file */
+		vmobj = vm_obj_alloc_init();
+		vmobj->priv.file = mapfile;
 	}
 
 	printf("%s: Mapping 0x%x - 0x%x\n", __FUNCTION__, map_address,
 	       map_address + pages * PAGE_SIZE);
 
 	/* See if it overlaps or is mergeable to an existing vma. */
-	if (find_unmapped_area(&vma, mapfile, pfn_start, pages, flags,
+	if (find_unmapped_area(&vma, pfn_start, pages, flags,
 			       &t->vm_area_list) < 0)
 		return -EINVAL;	/* Indicates overlap. */
 
diff --git a/tasks/mm0/src/proc.c b/tasks/mm0/src/proc.c
index d3cfb2e..44464d7 100644
--- a/tasks/mm0/src/proc.c
+++ b/tasks/mm0/src/proc.c
@@ -15,76 +15,100 @@
 #include <task.h>
 #include <proc.h>
 
-static void *zpage_p;
+static void *zpage_phys;
 static struct page *zpage;
+static struct vm_file *devzero;
 
-static struct vm_object devzero;
-
+/* TODO: Associate devzero with zero page */
 void init_zero_page(void)
 {
-	void *zpage_v;
-	zpage_p = alloc_page(1);
-	zpage = phys_to_page(zpage_p);
+	void *zpage_virt;
+	zpage_phys = alloc_page(1);
+	zpage = phys_to_page(zpage_phys);
 
 	/* Map it to self */
-	zpage_v = l4_map_helper(zpage_p, 1);
+	zpage_virt = l4_map_helper(zpage_phys, 1);
 
 	/* Zero it */
-	memset(zpage_v, 0, PAGE_SIZE);
+	memset(zpage_virt, 0, PAGE_SIZE);
 
 	/* Unmap it */
-	l4_unmap_helper(zpage_v, 1);
+	l4_unmap_helper(zpage_virt, 1);
 
 	/* Update page struct. All other fields are zero */
+	spin_lock(&page->lock);
 	zpage->count++;
+	spin_unlock(&page->lock);
+
 }
 
 #define VM_OBJ_MASK		0xFFFF
 #define VM_OBJ_DEVZERO		(1 << 0)	/* Devzero special file */
 #define VM_OBJ_FILE		(1 << 1)	/* Regular VFS file */
 #define VM_OBJ_SHADOW		(1 << 2)	/* Shadow of another object */
+#define VM_OBJ_COW		(1 << 3)	/* Copy-on-write semantics */
+
+struct vm_object *get_devzero(void)
+{
+	return &devzero;
+}
+
+struct page *get_zero_page(void)
+{
+
+	/* Update zero page struct. */
+	spin_lock(&page->lock);
+	zpage->count++;
+	spin_unlock(&page->lock);
+
+	return zpage;
+}
+
+void put_zero_page(void)
+{
+	spin_lock(&page->lock);
+	zpage->count--;
+	spin_unlock(&page->lock);
+
+	BUG_ON(zpage->count < 0);
+}
+
+#define vm_object_to_file(obj)	\
+	(struct vm_file *)container_of(obj, struct vm_file, vm_obj)
 
 /* Returns the page with given offset in this vm_object */
-struct page *devzero_pager_page_in(struct vm_object *vm_obj, unsigned long f_offset)
+struct page *devzero_pager_page_in(struct vm_object *vm_obj,
+				   unsigned long page_offset)
 {
+	struct vm_file *devzero = container_of(vm_obj, struct vm_file, vm_obj);
+	struct page *zpage = devzero->priv_data;
+
+	/* Update zero page struct. */
+	spin_lock(&page->lock);
+	zpage->count++;
+	spin_unlock(&page->lock);
+
 	return zpage;
 }
 
 struct vm_pager devzero_pager {
-	page_in = devzero_pager_page_int,
+	.page_in = devzero_pager_page_in,
 };
 
 void init_devzero(void)
 {
 	init_zero_page();
 
-	INIT_LIST_HEAD(&devzero.page_cache);
 	INIT_LIST_HEAD(&devzero.list);
 	INIT_LIST_HEAD(&devzero.shadows);
+	INIT_LIST_HEAD(&devzero.page_cache);
 
 	/* Devzero has infinitely many pages ;-) */
 	devzero.npages = -1;
-	devzero.type = VM_OBJ_FILE;
+	devzero.type = VM_OBJ_DEVZERO;
 	devzero.pager = &devzero_pager;
 }
 
-struct vm_file *get_devzero(void)
-{
-	return &devzero;
-}
-
-void *get_zero_page(void)
-{
-	zpage->count++;
-	return zpage_p;
-}
-
-void put_zero_page(void)
-{
-	zpage->count--;
-	BUG_ON(zpage->count < 0);
-}
-
 /* Allocates and fills in the env page. This is like a pre-faulted file. */
 int task_populate_env(struct task *task)
 {
@@ -123,22 +147,17 @@ int task_populate_env(struct task *task)
 	return 0;
 }
 
-
-#define TASK_DATA_VNUM	1
-#define TASK_STACK_VNUM	2
-#define TASK_ENV_VNUM	3
-
 /*
  * For a task that is about to execute, this dynamically
  * generates its environment file, and environment data.
  */
 int task_setup_vm_objects(struct tcb *t)
 {
-	struct proc_files *pf = &t->proc_files;
+	struct proc_vm_objects *po = &t->proc_vm_objects;
 
-	if (IS_ERR(pf->stack_file = vmfile_alloc_init()))
+	if (IS_ERR(pf->stack = vmfile_alloc_init()))
 		return (int)t->stack_file;
-	if (IS_ERR(pf->env_file = vmfile_alloc_init()))
+	if (IS_ERR(pf->env = vmfile_alloc_init()))
 		return (int)t->env_file;
 	if (IS_ERR(pf->env_file = vmfile_alloc_init()))
 		return (int)t->data_file;
diff --git a/tasks/mm0/src/task.c b/tasks/mm0/src/task.c
index 1a27682..d9bc988 100644
--- a/tasks/mm0/src/task.c
+++ b/tasks/mm0/src/task.c
@@ -41,36 +41,20 @@ struct tcb *find_task(int tid)
 	return 0;
 }
 
-#if 0
-void dump_tasks(void)
+struct tcb *tcb_alloc_init(void)
 {
-	struct tcb *t;
+	struct tcb *task;
 
-	list_for_each_entry(t, &tcb_head.list, list) {
-		printf("Task %s: id/spid: %d/%d\n", &t->name[0], t->tid, t->spid);
-		printf("Task vm areas:\n");
-		dump_vm_areas(t);
-		printf("Task swapfile:\n");
-		dump_task_swapfile(t);
-	}
-}
-#endif
-
-
-struct tcb *create_init_tcb(struct tcb_head *tcbs)
-{
-	struct tcb *task = kzalloc(sizeof(struct tcb));
+	if (!(task = kzalloc(sizeof(struct tcb))))
+		return PTR_ERR(-ENOMEM);
 
 	/* Ids will be acquired from the kernel */
 	task->tid = TASK_ID_INVALID;
 	task->spid = TASK_ID_INVALID;
+
+	/* Initialise its lists */
 	INIT_LIST_HEAD(&task->list);
 	INIT_LIST_HEAD(&task->vm_area_list);
-	list_add_tail(&task->list, &tcbs->list);
-	tcbs->total++;
-
-	/* Allocate a utcb virtual address */
-	task->utcb_address = (unsigned long)utcb_vaddr_new();
 
 	return task;
 }
@@ -78,15 +62,15 @@ struct tcb *create_init_tcb(struct tcb_head *tcbs)
 int start_boot_tasks(struct initdata *initdata, struct tcb_head *tcbs)
 {
 	int err;
-	struct vm_file *file;
 	struct svc_image *img;
 	unsigned int sp, pc;
 	struct tcb *task;
 	struct task_ids ids;
-	struct bootdesc *bd = initdata->bootdesc;
+	struct bootdesc *bd;
+	struct vm_object *vm_obj;
 
+	bd = initdata->bootdesc;
 	INIT_LIST_HEAD(&tcb_head.list);
-	INIT_LIST_HEAD(&initdata->boot_file_list);
 
 	for (int i = 0; i < bd->total_images; i++) {
 		img = &bd->images[i];
@@ -113,16 +97,17 @@ int start_boot_tasks(struct initdata *initdata, struct tcb_head *tcbs)
 
 		/* Create a task and use returned space and thread ids. */
 		printf("New task with id: %d, space id: %d\n", ids.tid, ids.spid);
-		task = create_init_tcb(tcbs);
+		task = tcb_alloc_init(tcbs);
 		task->tid = ids.tid;
 		task->spid = ids.spid;
 
-		/*
-		 * For boot files, we use the physical address of the memory
-		 * file as its mock-up inode.
-		 */
-		file = vmfile_alloc_init();
-		file->vnum = img->phys_start;
+		/* Allocate a utcb virtual address */
+		task->utcb_address = (unsigned long)utcb_vaddr_new();
+
+		/* Allocate the first vm_object we want to map */
+		vm_obj = vm_obj_alloc_init();
+		vm_obj->priv.img = img;
+
 		file->length = img->phys_end - img->phys_start;
 		file->pager = &boot_file_pager;
 		list_add(&file->list, &initdata->boot_file_list);
diff --git a/tasks/mm0/src/vm_object.c b/tasks/mm0/src/vm_object.c
index 856aaa8..8f940b2 100644
--- a/tasks/mm0/src/vm_object.c
+++ b/tasks/mm0/src/vm_object.c
@@ -9,9 +9,12 @@
 #include <kmalloc/kmalloc.h>
 
 
-/* Global list of in-memory vm files. */
+/* Global list of in-memory vm objects. */
 LIST_HEAD(vm_object_list);
 
+/* Global list of in-memory vm files */
+LIST_HEAD(vm_file_list);
+
 /* Allocate and initialise a vmfile, and return it */
 struct vm_object *vm_object_alloc_init(void)
 {