42.2 Introduction

IcePatch2 is an efficient file patching service that is easy to configure and use. It includes the following components:

• the IcePatch server (icepatch2server)

• a text-based IcePatch client (icepatch2client)

• a text-based tool to compress files and calculate checksums (icepatch2calc)

• a Slice API and C++ convenience library for developing custom IcePatch2 clients

As with all Ice services, IcePatch2 can be configured to use Ice facilities such as Glacier2 for firewall support and IceSSL for secure communication.

IcePatch2 is conceptually quite simple. The server is given responsibility for a file system directory (the data directory) containing the files and subdirectories that are to be distributed to IcePatch2 clients. You use icepatch2calc to compress these files and to generate an index containing a checksum for each file. The server transmits the compressed files to the client, which recreates the data directory and its contents on the client side, patching any files that have changed since the previous run.

IcePatch2 is efficient: transfer rates for files are comparable to what you would get using ftp.