diff --git a/.vscode/settings.json b/.vscode/settings.json
index 535e523..dbd0e77 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -21,6 +21,9 @@
 		"os.h": "c",
 		"os_core.h": "c",
 		"file.h": "c",
-		"xiosbase": "c"
+		"xiosbase": "c",
+		"iterator": "c",
+		"memory": "c",
+		"format": "c"
 	}
 }
\ No newline at end of file
diff --git a/code/base/arena.c b/code/base/arena.c
index dcee4be..d4c0138 100644
--- a/code/base/arena.c
+++ b/code/base/arena.c
@@ -11,134 +11,35 @@
 
 //- rjf: arena creation/destruction
 
-#if 0
-internal Arena*
-arena_alloc_(ArenaParams *params)
-{
-  // rjf: round up reserve/commit sizes
-  U64 reserve_size = params->reserve_size;
-  U64 commit_size = params->commit_size;
-  if(params->flags & ArenaFlag_LargePages)
-  {
-    reserve_size = AlignPow2(reserve_size, os_get_system_info()->large_page_size);
-    commit_size  = AlignPow2(commit_size,  os_get_system_info()->large_page_size);
-  }
-  else
-  {
-    reserve_size = AlignPow2(reserve_size, os_get_system_info()->page_size);
-    commit_size  = AlignPow2(commit_size,  os_get_system_info()->page_size);
-  }
-  
-  // rjf: reserve/commit initial block
-  void *base = params->optional_backing_buffer;
-  if(base == 0)
-  {
-    if(params->flags & ArenaFlag_LargePages)
-    {
-      base = os_reserve_large(reserve_size);
-      os_commit_large(base, commit_size);
-    }
-    else
-    {
-      base = os_reserve(reserve_size);
-      os_commit(base, commit_size);
-    }
-  }
-  
-  // rjf: panic on arena creation failure
-#if OS_FEATURE_GRAPHICAL
-  if(Unlikely(base == 0))
-  {
-    os_graphical_message(1, str8_lit("Fatal Allocation Failure"), str8_lit("Unexpected memory allocation failure."));
-    os_abort(1);
-  }
-#endif
-  
-  // rjf: extract arena header & fill
-  Arena *arena = (Arena *)base;
-  arena->current = arena;
-  arena->flags = params->flags;
-  arena->cmt_size = (U32)params->commit_size;
-  arena->res_size = params->reserve_size;
-  arena->base_pos = 0;
-  arena->pos = ARENA_HEADER_SIZE;
-  arena->cmt = commit_size;
-  arena->res = reserve_size;
-  AsanPoisonMemoryRegion(base, commit_size);
-  AsanUnpoisonMemoryRegion(base, ARENA_HEADER_SIZE);
-  return arena;
-}
-#endif
-
 Arena*
 arena_alloc_(ArenaParams* params)
 {
-	  // rjf: round up reserve/commit sizes
-	  U64 reserve_size = params->reserve_size;
-	  U64 commit_size  = params->commit_size;
+	B32 is_virtual = false;
 
+	// This composite arena has the ability to decide a default behavior for allocation 
 
-	  if(params->flags & ArenaFlag_LargePages)
-	  {
-		reserve_size = align_pow2(reserve_size, os_get_system_info()->large_page_size);
-		commit_size  = align_pow2(commit_size,  os_get_system_info()->large_page_size);
-	  }
-	  else
-	  {
-		reserve_size = align_pow2(reserve_size, os_get_system_info()->page_size);
-		commit_size  = align_pow2(commit_size,  os_get_system_info()->page_size);
-	  }
+	void* base = alloc(params->backing, params->block_size);
 	  
-	  // rjf: reserve/commit initial block
-	  void *base = params->optional_backing_buffer;
-	  if(base == 0)
-	  {
-		if(params->flags & ArenaFlag_LargePages)
-		{
-		  base = os_reserve_large(reserve_size);
-		  os_commit_large(base, commit_size);
-		}
-		else
-		{
-		  base = os_reserve(reserve_size);
-		  os_commit(base, commit_size);
-		}
-	  }
-	  
-	  // rjf: panic on arena creation failure
+	// rjf: panic on arena creation failure
 	#if OS_FEATURE_GRAPHICAL
-	  if(Unlikely(base == 0))
-	  {
-		os_graphical_message(1, str8_lit("Fatal Allocation Failure"), str8_lit("Unexpected memory allocation failure."));
-		os_abort(1);
-	  }
+		if(unlikely(base == 0))
+		{
+			os_graphical_message(1, str8_lit("Fatal Allocation Failure"), str8_lit("Unexpected memory allocation failure."));
+			os_abort(1);
+		}
 	#endif
 	  
-	  // rjf: extract arena header & fill
-	  Arena *arena = (Arena *)base;
-	  arena->current = arena;
-	  arena->flags = params->flags;
-	  arena->cmt_size = (U32)params->commit_size;
-	  arena->res_size = params->reserve_size;
-	  arena->base_pos = 0;
-	  arena->pos = ARENA_HEADER_SIZE;
-	  arena->cmt = commit_size;
-	  arena->res = reserve_size;
-	  AsanPoisonMemoryRegion(base, commit_size);
-	  AsanUnpoisonMemoryRegion(base, ARENA_HEADER_SIZE);
-	  return arena;
-}
+	// rjf: extract arena header & fill
+	Arena* arena      = (Arena*) base;
+	arena->current    = arena;
+	arena->backing    = params->backing;
+	arena->pos        = size_of(Arena);
+	arena->block_size = params->block_size;
+	arena->flags      = params->flags;
 
-// Note(Ed): INLINED
-// internal void
-// arena_release(Arena *arena)
-// {
-//   for(Arena *n = arena->current, *prev = 0; n != 0; n = prev)
-//   {
-//     prev = n->prev;
-//     os_release(n, n->res);
-//   }
-// }
+	asan_unpoison_memory_region(base, sizeof(Arena));
+	return arena;
+}
 
 //- rjf: arena push/pop core functions
 
@@ -247,16 +148,16 @@ arena_pop(Arena *arena, U64 amt)
 
 //- rjf: temporary arena scopes
 
-internal Temp
+internal TempArena
 temp_begin(Arena *arena)
 {
-  U64 pos = arena_pos(arena);
-  Temp temp = {arena, pos};
+  U64       pos  = arena_pos(arena);
+  TempArena temp = {arena, pos};
   return temp;
 }
 
 internal void
-temp_end(Temp temp)
+temp_end(TempArena temp)
 {
   arena_pop_to(temp.arena, temp.pos);
 }
diff --git a/code/base/arena.h b/code/base/arena.h
index 7d357c8..96de5ec 100644
--- a/code/base/arena.h
+++ b/code/base/arena.h
@@ -19,17 +19,19 @@
 typedef U32 ArenaFlags;
 enum
 {
-	ArenaFlag_NoChain    = ( 1 << 0),
-	ArenaFlag_LargePages = ( 1 << 1),
+	// Don't chain this arena
+	ArenaFlag_NoChain      = (1 << 0), 
+	// Only works if backing is virtual memory, will allocate a new backing VArena when the current block exhausts
+	// Otherwise will assume backing can chain multiple block_size arenas until failure.
+	ArenaFlag_ChainVirtual = (1 << 1),
 };
 
 typedef struct ArenaParams ArenaParams;
 struct ArenaParams
 {
-	ArenaFlags flags;
-	U64        reserve_size;
-	U64        commit_size;
-	void*      optional_backing_buffer;
+	AllocatorInfo backing;
+	ArenaFlags    flags;
+	U64           block_size; // If chaining VArenas set this to the reserve size
 };
 
 /* NOTE(Ed): This is a combination of several concepts into a single interface:
@@ -44,18 +46,14 @@ struct ArenaParams
 typedef struct Arena Arena;
 struct Arena
 {
-	AllocatorInfo backing;
 	Arena*        prev;    // previous arena in chain
 	Arena*        current; // current arena in chain
-	ArenaFlags    flags;
-	U32           cmt_size;
-	U64           res_size;
-	U64           base_pos;
+	AllocatorInfo backing;
 	U64           pos;
-	U64           cmt;
-	U64           res;
+	U64           block_size;
+	ArenaFlags    flags;
 };
-static_assert(sizeof(Arena) <= ARENA_HEADER_SIZE, "sizeof(Arena) <= MD_ARENA_HEADER_SIZE");
+static_assert(size_of(Arena) <= ARENA_HEADER_SIZE, "sizeof(Arena) <= ARENA_HEADER_SIZE");
 
 typedef struct TempArena TempArena;
 struct TempArena
@@ -67,12 +65,12 @@ struct TempArena
 ////////////////////////////////
 //~ rjf: Arena Functions
 
-MD_API void* arena_allocator_proc(void* allocator_data, AllocType type, SSIZE size, SSIZE alignment, void* old_memory, SSIZE old_size, U64 flags);
+MD_API void* arena_allocator_proc(void* allocator_data, AllocatorMode mode, SSIZE size, SSIZE alignment, void* old_memory, SSIZE old_size, U64 flags);
 
 //- rjf: arena creation/destruction
 
 MD_API Arena* arena_alloc_(ArenaParams *params);
-#define       arena_alloc(...) arena_alloc_( & ( ArenaParams) { .reserve_size = MB(64), .commit_size = KB(64), __VA_ARGS__ } )
+#define       arena_alloc(...) arena_alloc_( & ( ArenaParams) { .backing = {}, .reserve_size = MB(64), .commit_size = KB(64), __VA_ARGS__ } )
 
 void arena_release(Arena *arena);
 
@@ -109,9 +107,6 @@ arena_release(Arena* arena)
 	for (Arena* n = arena->current, *prev = 0; n != 0; n = prev)
 	{
 		prev = n->prev;
-		// os_release(n, n->res);
 		alloc_free(arena->backing, n);
 	}
 }
-
-
diff --git a/code/base/memory.h b/code/base/memory.h
index 1b3f4ce..f0e87ac 100644
--- a/code/base/memory.h
+++ b/code/base/memory.h
@@ -4,6 +4,7 @@
 #	include "linkage.h"
 #	include "macros.h"
 #	include "platform.h"
+#	include "base_types.h"
 #endif
 
 
@@ -200,19 +201,19 @@ void* mem_move( void* destination, void const* source, SSIZE byte_count )
 	{
 		if ( to_uptr(src_ptr) % size_of( SSIZE ) == to_uptr(dest_ptr) % size_of( SSIZE ) )
 		{
-			while ( pcast( UPTR, dest_ptr) % size_of( ssize ) )
+			while ( pcast( UPTR, dest_ptr) % size_of( SSIZE ) )
 			{
 				if ( ! byte_count-- )
 					return destination;
 
 				*dest_ptr++ = *src_ptr++;
 			}
-			while ( byte_count >= size_of( ssize ) )
+			while ( byte_count >= size_of( SSIZE ) )
 			{
 				* rcast(SSIZE*, dest_ptr)  = * rcast(SSIZE const*, src_ptr);
-				byte_count -= size_of( ssize );
-				dest_ptr   += size_of( ssize );
-				src_ptr    += size_of( ssize );
+				byte_count -= size_of( SSIZE );
+				dest_ptr   += size_of( SSIZE );
+				src_ptr    += size_of( SSIZE );
 			}
 		}
 		for ( ; byte_count; byte_count-- )
@@ -301,7 +302,7 @@ void* mem_set( void* destination, U8 fill_byte, SSIZE byte_count )
 	byte_count   -= align_offset;
 
 	{
-		u64 fill_doubleword = ( scast( U64, fill_word) << 32 ) | fill_word;
+		U64 fill_doubleword = ( scast( U64, fill_word) << 32 ) | fill_word;
 		while ( byte_count > 31 )
 		{
 			* rcast( U64*, dest_ptr + 0 )  = fill_doubleword;
diff --git a/code/base/memory_substrate.c b/code/base/memory_substrate.c
index a3d4a6f..7a88fd7 100644
--- a/code/base/memory_substrate.c
+++ b/code/base/memory_substrate.c
@@ -4,6 +4,7 @@
 #	include "../os/os.h"
 #endif
 
+#ifdef MD_HEAP_ANALYSIS
 #define GEN_HEAP_STATS_MAGIC 0xDEADC0DE
 
 typedef struct _heap_stats _heap_stats;
@@ -47,8 +48,9 @@ struct _heap_alloc_info
 	SSIZE size;
 	void* physical_start;
 };
+#endif
 
-void* heap_allocator_proc( void* allocator_data, AllocType type, SSIZE size, SSIZE alignment, void* old_memory, SSIZE old_size, U64 flags )
+void* heap_allocator_proc( void* allocator_data, AllocatorMode mode, SSIZE size, SSIZE alignment, void* old_memory, SSIZE old_size, U64 flags )
 {
 	void* ptr = nullptr;
 	// unused( allocator_data );
@@ -62,7 +64,7 @@ void* heap_allocator_proc( void* allocator_data, AllocType type, SSIZE size, SSI
 	ssize track_size           = max( alloc_info_size, alignment ) + alloc_info_remainder;
 	switch ( type )
 	{
-		case EAllocation_FREE :
+		case EAllocatorMode_FREE :
 			{
 				if ( ! old_memory )
 					break;
@@ -72,7 +74,7 @@ void* heap_allocator_proc( void* allocator_data, AllocType type, SSIZE size, SSI
 				old_memory = alloc_info->physical_start;
 			}
 			break;
-		case EAllocation_ALLOC :
+		case EAllocatorMode_ALLOC :
 			{
 				size += track_size;
 			}
@@ -82,76 +84,83 @@ void* heap_allocator_proc( void* allocator_data, AllocType type, SSIZE size, SSI
 	}
 #endif
 
-	switch ( type )
+	switch ( mode )
 	{
-#if defined( COMPILER_MSVC ) || ( defined( COMPILER_GCC ) && defined( OS_WINDOWS ) ) || ( defined( COMPILER_TINYC ) && defined( OS_WINDOWS ) )
-		case EAllocType_ALLOC :
+	#if defined( COMPILER_MSVC ) || ( defined( COMPILER_GCC ) && defined( OS_WINDOWS ) ) || ( defined( COMPILER_TINYC ) && defined( OS_WINDOWS ) )
+		case AllocatorMode_ALLOC:
+		{
 			ptr = _aligned_malloc( size, alignment );
 			if ( flags & ALLOCATOR_FLAG_CLEAR_TO_ZERO )
 				zero_size( ptr, size );
-			break;
-		case EAllocType_FREE :
+		}
+		break;
+
+		case AllocatorMode_FREE:
 			_aligned_free( old_memory );
-			break;
-		case EAllocType_RESIZE :
-			{
-				AllocatorInfo a = heap();
-				ptr             = default_resize_align( a, old_memory, old_size, size, alignment );
-			}
-			break;
+		break;
 
-#elif defined( OS_LINUX ) && ! defined( CPU_ARM ) && ! defined( COMPILER_TINYC )
+		case AllocatorMode_FREE_ALL:
+		{
+			AllocatorInfo a = heap();
+			ptr             = default_resize_align( a, old_memory, old_size, size, alignment );
+		}
+		break;
+
+	#elif defined( OS_LINUX ) && ! defined( CPU_ARM ) && ! defined( COMPILER_TINYC )
 		case EAllocation_ALLOC :
-			{
-				ptr = aligned_alloc( alignment, ( size + alignment - 1 ) & ~( alignment - 1 ) );
+		{
+			ptr = aligned_alloc( alignment, ( size + alignment - 1 ) & ~( alignment - 1 ) );
 
-				if ( flags & GEN_ALLOCATOR_FLAG_CLEAR_TO_ZERO )
-				{
-					zero_size( ptr, size );
-				}
+			if ( flags & GEN_ALLOCATOR_FLAG_CLEAR_TO_ZERO )
+			{
+				zero_size( ptr, size );
 			}
-			break;
+		}
+		break;
 
 		case EAllocation_FREE :
-			{
-				free( old_memory );
-			}
-			break;
+		{
+			free( old_memory );
+		}
+		break;
 
 		case EAllocation_RESIZE :
-			{
-				AllocatorInfo a = heap();
-				ptr             = default_resize_align( a, old_memory, old_size, size, alignment );
-			}
-			break;
-#else
+		{
+			AllocatorInfo a = heap();
+			ptr             = default_resize_align( a, old_memory, old_size, size, alignment );
+		}
+		break;
+	#else
 		case EAllocType_ALLOC :
-			{
-				posix_memalign( &ptr, alignment, size );
+		{
+			posix_memalign( &ptr, alignment, size );
 
-				if ( flags & ALLOCATOR_FLAG_CLEAR_TO_ZERO )
-				{
-					zero_size( ptr, size );
-				}
+			if ( flags & ALLOCATOR_FLAG_CLEAR_TO_ZERO )
+			{
+				zero_size( ptr, size );
 			}
-			break;
+		}
+		break;
 
 		case EAllocType_FREE :
-			{
-				free( old_memory );
-			}
-			break;
+		{
+			free( old_memory );
+		}
+		break;
 
 		case EAllocType_RESIZE :
-			{
-				AllocatorInfo a = heap();
-				ptr             = default_resize_align( a, old_memory, old_size, size, alignment );
-			}
-			break;
-#endif
+		{
+			AllocatorInfo a = heap();
+			ptr             = default_resize_align( a, old_memory, old_size, size, alignment );
+		}
+		break;
+	#endif
 
-		case EAllocType_FREE_ALL :
+		case AllocatorMode_FREE_ALL:
 			break;
+		
+		case AllocatorMode_QueryType:
+			return (void*) Heap
 	}
 
 #ifdef GEN_HEAP_ANALYSIS
@@ -172,6 +181,44 @@ void* heap_allocator_proc( void* allocator_data, AllocType type, SSIZE size, SSI
 
 void* vm_allocator_proc(void* allocator_data, AllocType type, SSIZE size, SSIZE alignment, void* old_memory, SSIZE old_size, U64 flags)
 {
+	void* result = nullptr;
 
+			// if(params->flags & ArenaFlag_LargePages)
+			// {
+			// 	base = os_reserve_large(reserve_size);
+			// 	os_commit_large(base, commit_size);
+			// }
+			// else
+			// {
+			// 	base = os_reserve(reserve_size);
+			// 	os_commit(base, commit_size);
+			// }
+
+	return result;
 }
 
+VMemory vm_alloc(VMemoryParams params)
+{
+	// rjf: round up reserve/commit sizes
+	U64 reserve_size = params->reserve_size;
+	U64 commit_size  = params->commit_size;
+
+	if(params->flags & ArenaFlag_LargePages)
+	{
+		reserve_size = align_pow2(reserve_size, os_get_system_info()->large_page_size);
+		commit_size  = align_pow2(commit_size,  os_get_system_info()->large_page_size);
+	}
+	else
+	{
+		reserve_size = align_pow2(reserve_size, os_get_system_info()->page_size);
+		commit_size  = align_pow2(commit_size,  os_get_system_info()->page_size);
+	}
+
+	// Allocate virtual memory
+	is_virtual = true;
+
+	VMemory vm = ;
+
+	// TODO(Ed): Move this to vmem?
+	asan_poison_memory_region(base, params->commit_size);
+}
diff --git a/code/base/memory_substrate.h b/code/base/memory_substrate.h
index dd8a2ea..914c32d 100644
--- a/code/base/memory_substrate.h
+++ b/code/base/memory_substrate.h
@@ -19,18 +19,29 @@
 #define MD__HAS_ZERO( x ) ( ( ( x ) - MD__ONES ) & ~( x ) & MD__HIGHS )
 #endif
 
-typedef U32 AllocType;
-enum AllocType enum_underlying(U32)
+// Return value of allocator_type
+typedef U32 AllocatorType;
+enum
 {
-	EAllocType_ALLOC,
-	EAllocType_FREE,
-	EAllocType_FREE_ALL,
-	EAllocType_RESIZE,
+	AllocatorType_Heap   = 0, // Genreal heap allocator
+	AllocatorType_VArena = 1, // Arena allocator backed by virtual address space
+	AllocatorType_FArena = 2, // Fixed arena backed back by a fixed size block of memory (usually a byte slice)
+	AllocatorType_Arena  = 3, // Composite arena used originally by RAD Debugger & Metadesk
 };
 
-typedef void*(AllocatorProc)( void* allocator_data, AllocType type, SSIZE size, SSIZE alignment, void* old_memory, SSIZE old_size, U64 flags );
+typedef U32 AllocatorMode;
+enum AllocatorMode enum_underlying(U32)
+{
+	AllocatorMode_ALLOC,
+	AllocatorMode_FREE,
+	AllocatorMode_FREE_ALL,
+	AllocatorMode_RESIZE,
+	AllocatorMode_QueryType,
+};
 
-typedef struct AllocatorInfo;
+typedef void*(AllocatorProc)( void* allocator_data, AllocatorMode type, SSIZE size, SSIZE alignment, void* old_memory, SSIZE old_size, U64 flags );
+
+typedef struct AllocatorInfo AllocatorInfo;
 struct AllocatorInfo
 {
 	AllocatorProc* proc;
@@ -50,6 +61,9 @@ enum AllocFlag
 #	define MD_DEFAULT_ALLOCATOR_FLAGS ( ALLOCATOR_FLAG_CLEAR_TO_ZERO )
 #endif
 
+// Allows the user to retrieve which type of allocator is being used.
+AllocatorType allocator_type(AllocatorInfo a);
+
 //! Allocate memory with default alignment.
 void* alloc( AllocatorInfo a, SSIZE size );
 
@@ -83,6 +97,7 @@ void* resize_align( AllocatorInfo a, void* ptr, SSIZE old_size, SSIZE new_size,
 //! Use this if you don't need a "fancy" resize allocation
 void* default_resize_align( AllocatorInfo a, void* ptr, SSIZE old_size, SSIZE new_size, SSIZE alignment );
 
+#ifdef MD_HEAP_ANALYSIS
 /* heap memory analysis tools */
 /* define GEN_HEAP_ANALYSIS to enable this feature */
 /* call zpl_heap_stats_init at the beginning of the entry point */
@@ -91,8 +106,9 @@ MD_API void  heap_stats_init( void );
 MD_API SSIZE heap_stats_used_memory( void );
 MD_API SSIZE heap_stats_alloc_count( void );
 MD_API void  heap_stats_check( void );
+#endif
 
-MD_API void* heap_allocator_proc( void* allocator_data, AllocType type, SSIZE size, SSIZE alignment, void* old_memory, SSIZE old_size, U64 flags );
+MD_API void* heap_allocator_proc( void* allocator_data, AllocatorMode mode, SSIZE size, SSIZE alignment, void* old_memory, SSIZE old_size, U64 flags );
 
 #ifndef heap
 //! The heap allocator backed by operating system's memory manager.
@@ -109,44 +125,83 @@ MD_API void* heap_allocator_proc( void* allocator_data, AllocType type, SSIZE si
 #define mfree( ptr ) free( heap(), ptr )
 #endif
 
-typedef U32 VMemoryFlags;
+/* Virtual Memory Arena
+	This is separate from the composite arena used by HMH/Casey Muratori/RJF
+	This arena stricly manages one reservation of the process's virtual address space.
+
+	Segregating this from composite Arena style causes more moremoy to be used for "allocator headers", however it allows
+	users of a library to have greater control over the allocation strategy used from their side instead of the library itself.
+
+	Like with the composite Arena, the VArena has its struct as the header of the reserve of memory.
+*/
+
+typedef U32 VArenaFlags;
 enum
 {
-	VMemoryFlag_NoChain    = (1 << 0),
-	VMemoryFlag_LargePages = (1 << 1),
+	VArenaFlag_LargePages = (1 << 0),
 };
 
-typedef struct VMemory_Params;
-struct VMemory_Params
+typedef struct VArenaParams VArenaParams;
+struct VArenaParams
 {
-	VMemoryFlags flags;
-	U64          reserve_size;
-	U64          commit_size;
-	// void*        optional_backing_buffer;
+	U64         base_addr;
+	VArenaFlags flags;
+	U64         reserve_size;
+	U64         commit_size;
 };
 
-typedef struct VMemory;
-struct VMemory
+typedef struct VArena VArena;
+struct VArena
 {
-	U32 cmt_size;
-	U32 res_size;
+	VArenaFlags flags;
 	U64 base_pos;
 	U64 cmt;
 	U64 res;
+	U64 res_size;
+	U64 cmt_size;
 };
 
-AllocatorInfo vm_allocator(VMemory* vm) {
-	AllocatorInfo info = { vm_allocator_proc, vm }
-	return info
+AllocatorInfo vm_allocator(VArena* vm) {
+	AllocatorInfo info = { vm_allocator_proc, vm };
+	return info;
 }
 
-MD_API void* vm_allocator_proc(void* allocator_data, AllocType type, SSIZE size, SSIZE alignment, void* old_memory, SSIZE old_size, U64 flags);
+VArena*      varena_alloc    (VArenaParams params);
+void         varena_commit   (VArena vm, SSIZE commit_size);
+VArenaParams varena_free     (VArena vm);
+SSIZE        varena_page_size(SSIZE* alignment_out);
+
+MD_API void* varena_allocator_proc(void* allocator_data, AllocatorMode mode, SSIZE size, SSIZE alignment, void* old_memory, SSIZE old_size, U64 flags);
+
+typedef struct ByteSlice ByteSlice;
+struct ByteSlice
+{
+	U8*   data;
+	SSIZE len;
+};
+
+// Fixed size arena
+typedef struct FArena FArena;
+struct FArena
+{
+	ByteSlice slice;
+	SSIZE     pos;
+};
+
+FArena farena_from_byteslice(ByteSlice slice);
+
+MD_API void* farena_allocator_proc(void* allocator_data, AllocatorMode mode, SSIZE size, SSIZE alignment, void* old_memory, SSIZE old_size, U64 flags);
 
 // Inlines
 
+inline
+AllocatorType allocator_type(AllocatorInfo a) {
+	return (AllocatorType) a.proc(a.data, AllocatorMode_QueryType, 0, 0, nullptr, 0, MD_DEFAULT_ALLOCATOR_FLAGS);
+}
+
 inline
 void* alloc_align( AllocatorInfo a, SSIZE size, SSIZE alignment ) {
-	return a.Proc( a.Data, EAllocType_ALLOC, size, alignment, nullptr, 0, MD_DEFAULT_ALLOCATOR_FLAGS );
+	return a.proc( a.data, AllocatorMode_ALLOC, size, alignment, nullptr, 0, MD_DEFAULT_ALLOCATOR_FLAGS );
 }
 
 inline
@@ -157,12 +212,12 @@ void* alloc( AllocatorInfo a, SSIZE size ) {
 inline
 void allocator_free( AllocatorInfo a, void* ptr ) {
 	if ( ptr != nullptr )
-		a.Proc( a.Data, EAllocType_FREE, 0, 0, ptr, 0, MD_DEFAULT_ALLOCATOR_FLAGS );
+		a.proc( a.data, AllocatorMode_FREE, 0, 0, ptr, 0, MD_DEFAULT_ALLOCATOR_FLAGS );
 }
 
 inline
 void free_all( AllocatorInfo a ) {
-	a.Proc( a.Data, EAllocType_FREE_ALL, 0, 0, nullptr, 0, MD_DEFAULT_ALLOCATOR_FLAGS );
+	a.proc( a.data, AllocatorMode_FREE_ALL, 0, 0, nullptr, 0, MD_DEFAULT_ALLOCATOR_FLAGS );
 }
 
 inline
@@ -172,7 +227,7 @@ void* resize( AllocatorInfo a, void* ptr, SSIZE old_size, SSIZE new_size ) {
 
 inline
 void* resize_align( AllocatorInfo a, void* ptr, SSIZE old_size, SSIZE new_size, SSIZE alignment ) {
-	return a.Proc( a.Data, EAllocType_RESIZE, new_size, alignment, ptr, old_size, MD_DEFAULT_ALLOCATOR_FLAGS );
+	return a.proc( a.data, AllocatorMode_RESIZE, new_size, alignment, ptr, old_size, MD_DEFAULT_ALLOCATOR_FLAGS );
 }
 
 inline
diff --git a/code/metadesk.h b/code/metadesk.h
index f2e8d28..f17b2c1 100644
--- a/code/metadesk.h
+++ b/code/metadesk.h
@@ -36,4 +36,3 @@ MD_NS_END
 
 // metagen
 
-