diff --git a/.hgignore b/.hgignore
--- a/.hgignore
+++ b/.hgignore
@@ -1,2 +1,3 @@
 ^src/__pycache__/
 ^\..*
+^temp/.*
diff --git a/src/db.py b/src/db.py
new file mode 100644
--- /dev/null
+++ b/src/db.py
@@ -0,0 +1,38 @@
+import sqlite3
+import time
+
+COMMIT_TIME=2 # s
+
+class DB:
+	def __init__(self,filename):
+		self.filename=filename
+		self.connection=sqlite3.connect(self.filename)
+		self.connection.row_factory=sqlite3.Row
+		self.commitTime=time.time()
+
+	def setup(self):
+		# !! err if exists
+		self.connection.execute("""create table `hashes` (
+			`sector_id` integer primary key,
+			`sector_hash` blob not null,
+			`updated` integer
+		)""")
+
+		self.connection.commit()
+
+	## Inserts hash into the DB.
+	#
+	# @param sectorHash bytes object containing the hash
+	def insertHash(self,sectorId,sectorHash):
+		# !! if not connection
+		res=self.connection.execute("""insert or replace into `hashes` (`sector_id`, `sector_hash`, `updated`)
+			values (?, ?, strftime('%s','now'))""", (sectorId,sectorHash))
+		t=time.time()
+		if t-self.commitTime > COMMIT_TIME:
+			self.connection.commit()
+			self.commitTime=t
+		return res
+
+	def listHashes(self):
+		# !! if not connection
+		return self.connection.execute("""select * from `hashes` order by `sector_id` asc""")
diff --git a/src/work.py b/src/work.py
--- a/src/work.py
+++ b/src/work.py
@@ -5,12 +5,65 @@ import sqlite3
 import math
 import pathlib
 import itertools
+import logging as log
+from itertools import zip_longest
+from db import DB
 
 BLOCK_SIZE=4096
 HASH_LEN=8
-DB="morevna.db"
-FILES_PER_DIR=100
+DB_NAME="morevna.db"
 FILE_COUNT=2**21
+TARGET_DIR="temp"
+
+log.basicConfig(level=log.DEBUG)
+
+class Pipeline:
+	def __init__(self,fileName):
+		self.fileName=fileName
+		self.db=DB(DB_NAME)
+		self.actions=[]
+
+	def setup(self):
+		self.db.setup()
+
+	def update(self):
+		log.info("starting update")
+		for (i,(chunk,storedHashRec)) in enumerate(zip_longest(self.chunks(), self.db.listHashes())):
+			if not chunk: break
+			hash=self.hash(chunk)
+			storedHash=(storedHashRec and storedHashRec["sector_hash"]) or b"\0"
+			if hash==storedHash: continue
+			log.info("updating sector %d, hash %s != stored %s", i, hash.hex(), storedHash.hex())
+			self.copyChunk(chunk,i)
+			self.db.insertHash(i,hash)
+		self.db.connection.commit()
+		log.info("update done")
+
+	def chunks(self):
+		with open(self.fileName, mode="br") as f: # !! buffering
+			data=f.read(BLOCK_SIZE)
+			while data:
+				yield data
+				data=f.read(BLOCK_SIZE)
+
+	@staticmethod
+	def hash(chunk):
+		return hashlib.sha256(chunk).digest()[:HASH_LEN]
+
+	def copyChunk(self,chunk,i):
+		path=pathlib.Path(TARGET_DIR).joinpath(Pipeline.getPath(("{0:0"+str(len(str(FILE_COUNT)))+"}").format(i)))
+		if not path.parent.exists(): path.parent.mkdir(parents=True) # !! no fail? existing file named as a dir
+		log.debug("writing file %s", path)
+		f=path.open(mode="wb")
+		f.write(chunk)
+		f.close()
+
+	@staticmethod
+	def getPath(name):
+		dirs=[name]
+		for i in range(2,len(name),2):
+			dirs.append(name[:-i])
+		return pathlib.Path(*reversed(dirs))
 
 def initDB():
 	conn=sqlite3.connect("morevna.db")
@@ -19,7 +72,7 @@ def initDB():
 	c.execute("""create table if not exists `hashes` (
 		`sector_id` integer primary key,
 		`sector_hash` blob not null,
-		`dirty` integer check(`dirty` in (0,1))
+		`updated` integer
 	)""")
 	
 	c.execute("""create index if not exists `dirty_index` on `hashes` (`dirty`)""")
@@ -36,13 +89,6 @@ def initHashes(fileName):
 		)
 		db.commit()
 
-def chunks(fileName):
-	with open(fileName, mode="br") as f:
-		data=f.read(BLOCK_SIZE)
-		while data:			
-			yield hashlib.sha256(data).digest()[:HASH_LEN]
-			data=f.read(BLOCK_SIZE)
-
 def hashes():
 	with sqlite3.connect(DB) as db:
 		handle=db.cursor()
@@ -127,8 +173,9 @@ hashFile="{0}-hash.dat".format(baseName)
 isoDate=datetime.datetime.now().strftime("%Y%m%dT%H%M%S")
 logFile="{0}-{1}.log".format(baseName,isoDate)
 
-if action=="init": initHashes(fileName)
-elif action=="update": findChanges(fileName)
-elif action=="transfer": transferChanges(sys.argv[3])
+pipeline=Pipeline(fileName)
+if action=="setup": pipeline.setup()
+elif action=="update": pipeline.update()
+#elif action=="transfer": transferChanges(sys.argv[3])
 else: print("bad action")