Update README.txt

README.txt

@@ -1,12 +1,12 @@
-BFT-SMaRt v1.0-beta
+BFT-SMaRt v1.1-beta
 ----------
 
 This package contains the BFT-SMaRt source code (src/), binary file (bin/), libraries needed (lib/), documentation (doc/), running scripts (runscripts/) and configuration files (config/).
 BFT-SMaRt requires the Java Runtime Environment version 1.7 or later.
 
------------- Important notice for developers -------------
+---------------- Important notice ------------------------
 
-This beta version of BFT-SMaRt offers the most stable execution via the class bftsmart.tom.server.defaultservices.DefaultRecoverable under Byzantine faults. Applications can also be implemente using bftsmart.tom.server.defaultservices.DefaultSingleRecoverable and bftsmart.tom.server.defaultservices.durability.DurabilityCoordinator, but they are not as stable as DefaultRecoverable. In future versions these classes will be properly tested and fixed.
+This beta version of BFT-SMaRt offers the most stable execution via the class bftsmart.tom.server.defaultservices.DefaultRecoverable under Byzantine faults. Applications can also be implemented using 'bftsmart.tom.server.defaultservices.DefaultSingleRecoverable' and 'bftsmart.tom.server.defaultservices.durability.DurabilityCoordinator', but they are not as stable as 'DefaultRecoverable'. In future versions these classes will be properly tested and fixed.
 
 ------------- How to run BFT-SMaRt -----------------------
 
@@ -30,6 +30,8 @@ You can run the counter demonstration by executing the following commands, from
 ./runscripts/smartrun.sh bftsmart.demo.counter.CounterServer 2
 ./runscripts/smartrun.sh bftsmart.demo.counter.CounterServer 3
 
+Important tip: Never forget to delete the config/currentView file after you modify config/hosts.config or config/system.config. If config/currentView exists, BFT-SMaRt always fetches the group configuration from this file first. Otherwise, BFT-SMaRt fetches information from the other files and creates config/currentView from scratch. Note that config/currentView only stores information related to the group of replicas. You do not need to delete this file if you want to enable the debugger or change the value of the timeout.
+
 #Start a client
 
 ./runscripts/smartrun.sh bftsmart.demo.counter.CounterClient 1001 <increment> [<number of operations>]
@@ -47,26 +49,40 @@ Other available demos:
   The server is bftmap.demo.bftmap.BFTMapServer and the clients are BFTMapClient for incremental inserts or BFTMapInteractiveClient for a command line client. Parameters to run the BFTMap demo are displayed when attempts to start the servers and clients are made without parameters.
 - YCSB. You can run a Yahoo! Cloud Serving Benchmark with BFT-SMaRt by executing the startReplicaYCSB.sh and ycsbClient.sh
   scripts located in the main folder.
+
+Important tip: always make sure that each client uses a unique ID. Otherwise, clients may not be able to complete their operations.
 
-------------- Additional Information ------------------
+---------- State transfer protocol(s) --------------
 
 BFT-SMaRt offers two state transfer protocols. The first is a basic protocol that can be used by extending the class bftsmart.tom.server.defaultservices.DefaultRecoverable that logs requests into memory and periodically takes snapshots of the application state.
 
 The second, more advanced protocol can be used by extending the class bftsmart.tom.server.defaultservices.durability.DurabilityCoordinator. This protocol stores its logs to disk. To mitigate the latency of writing to disk, such tasks is done in batches and in parallel with the requests' execution. Additionally, the snapshots are taken at different points of the execution in different replicas.
 
-The library also implements a reconfiguration protocol, that you can use to add/remove replicas from the initial group. You can add/remove replicas on-the-fly by executing the following commands:
+Important tip: regardless of the chosen protocol, developers must avoid using Java API objects like HashSet or HashMap, and use TreeSet or TreeMap instead. This is because serialization of Hash* objects is not deterministic, i.e, it generates different results for equal objects. This will lead to problems after more than 'f' replicas used the state transfer protocol to recover from failures.
+
+----------- Group reconfiguration ------------------
+
+The library also implements a protocol to reconfiguration protocol that can be used to add/remove replicas from the initial group. You can add/remove replicas on-the-fly by executing the following commands:
 
 ./runscripts/smartrun.sh bftsmart.reconfiguration.VMServices <smart id> <ip address> <port> (to add a replica to the group)
 ./runscripts/smartrun.sh bftsmart.reconfiguration.VMServices <smart id> (to remove a replica from the group)
 
+Important tip: everytime you invoke this procedure, you must make sure that all replicas and the host where you invoke the above commands have the latest config/currentView file. The current implementation of BFT-SMaRt does not provide any mechanism to distribute this file, so you will need to distribute the file on your own (e.g., using the 'scp' command). You also need to make sure that any client that starts executing can read from the latest config/currentView file.
+
+---------- BFT-SMaRt under crash faults ------------
+
 You can run BFT-SMaRt in crash-faults only mode by setting the "system.bft" parameter in the configuration file to "false". This mode requires less replicas to execute, but will not withstand full Byzantine behavior from compromised replicas.
 
+------ Generating public/private key pairs ---------
+
 If you need to generate public/private keys for more replicas or clients, you can use the following command:
 
 ./runscripts/smartrun.sh bftsmart.tom.util.RSAKeyPairGenerator <id> <key size>
 
 Keys are stored in the config/keys folder. The command above creates key pairs both for clients and replicas.
 
+----- Additional information and publications ------
+
 Finally, if you are interested in learning more about BFT-SMaRt, you can read:
 
 - The technical report at the handler: http://hdl.handle.net/10455/6897