DeltaSync
Encyclopedia
DeltaSync is a proprietary
Microsoft
communications protocol
for synchronizing web services with offline clients. Windows Live Hotmail is exposed to offline clients
using DeltaSync, and Outlook Connector
and the Windows Live Mail
client use it for offline access. Microsoft is pushing for this protocol instead of POP3 or IMAP4 for supporting various advanced features like contacts, calendar, notes synchronizing. Using the DeltaSync protocol, Microsoft intends to provide a common platform for any compatible device to implement a client which can two-way synchronize mail, contacts, calendar and notes.
. In April 2008, Microsoft sent an email warning that WebDAV would no longer be supported after 30 June 2008. However, in May 2008 Microsoft stated that they would be "postponing the transition deadline previously announced" to allow customers more time to "evaluate alternative solutions". In June 2009 Microsoft announced that WebDav support would finally end on 1 September 2009
Following this header is a series of compressed data blocks with the following structure
This is followed by 256 bytes of decompression table and finally the actual compressed data.
Proprietary protocol
In telecommunications, a proprietary protocol is a communications protocol owned by a single organization or individual.-Enforcement:Proprietors may enforce restrictions through patents and by keeping the protocol specification a trade secret...
Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
communications protocol
Communications protocol
A communications protocol is a system of digital message formats and rules for exchanging those messages in or between computing systems and in telecommunications...
for synchronizing web services with offline clients. Windows Live Hotmail is exposed to offline clients
Offline reader
An offline reader is computer software that downloads e-mail, newsgroup posts or web pages, making them available when the computer is offline: not connected to the Internet or, in the late 20th century, bulletin board systems...
using DeltaSync, and Outlook Connector
Microsoft Office Outlook Connector
Microsoft Outlook Hotmail Connector is a free add-in for Microsoft Outlook that allows users to access Windows Live Hotmail or Office Live Mail accounts through Microsoft Outlook....
and the Windows Live Mail
Windows Live Mail
Windows Live Mail is a free of charge email client from Microsoft's Windows Live set of products. It is intended to be a successor for Outlook Express on Windows XP and Windows Mail on Windows Vista...
client use it for offline access. Microsoft is pushing for this protocol instead of POP3 or IMAP4 for supporting various advanced features like contacts, calendar, notes synchronizing. Using the DeltaSync protocol, Microsoft intends to provide a common platform for any compatible device to implement a client which can two-way synchronize mail, contacts, calendar and notes.
History
In January 2007, Microsoft announced DeltaSync as the replacement for WebDAVWebDAV
Web-based Distributed Authoring and Versioning is a set of methods based on the Hypertext Transfer Protocol that facilitates collaboration between users in editing and managing documents and files stored on World Wide Web servers...
. In April 2008, Microsoft sent an email warning that WebDAV would no longer be supported after 30 June 2008. However, in May 2008 Microsoft stated that they would be "postponing the transition deadline previously announced" to allow customers more time to "evaluate alternative solutions". In June 2009 Microsoft announced that WebDav support would finally end on 1 September 2009
Format Details
The DeltaSync compression code produces a stream with a four byte magic number of "HU01" followed by the stream headerHU01 Header
| Offset | Description |
|---|---|
| 0 | 'HU01' magic number |
| 4 | header size (should be greater than or equal to 28) |
| 8..31 | Unknown |
| 32 | Decompressed file size |
Following this header is a series of compressed data blocks with the following structure
SCBH Header
| Offset | Description |
|---|---|
| 0 | 'SCBH' magic number |
| 4 | header size |
| 8 | Decompressed block size |
| 12 | Block CRC? |
| 16 | Compressed block size |
This is followed by 256 bytes of decompression table and finally the actual compressed data.
External links
- Microsoft Office Outlook Connector
- Daniel Parnell is reverse engineering DeltaSync
- Daniel Parnell has released the source for DeltaSync decompression code
- another person reverse engineering DeltaSync
- POP3 access to Windows Live email in selected countries
- Get Contacts and Mails with DeltaSync
- Java implementation of the DeltaSync protocol which so far implements synchronization of folders and messages