Windows 7 ‘HomeGroup’: rebirth of Longhorn ‘Castle’?

Windows 7 HomeGroup

Half a decade after its initial conception, Windows Codename Longhorn still proves to be a great source of ideas. One of which known as “Castle”, appears to have been revived to be a feature of Windows 7 as “HomeGroup”.

We know what Workgroups are – Microsoft’s implementation of a peer-to-peer computer network for Windows to share files, printers and other resources. So what are HomeGroups?

That mystery didn’t last very long as someone was kind enough to point me to some well-aged reading material which described exactly what Castle was, and the same person claims what HomeGroups are about to become.

The document I am referencing is the Windows “Longhorn” Pre-Release Privacy Statement ( hosted), published October 24, 2003 for those of you playing along. This was a legal document to give users of pre-release versions of Longhorn an outline of the data collection and use practices of any network-related features that was in Longhorn at the time. Castle happens to be one of them.

It writes, I quote and highlight,


What This Feature Does:
The “castle” feature allows users to have the networking functionality of the domain, including roaming the user’s profile, machine trust and having a consistent user identity throughout the network. The main difference with Castle is that users do not have to setup a dedicated machine, such as a domain controller, to maintain the trust and identity relationship. It also makes it easy to share and access files on those computers. Each computer on the same subnet can discover and join an existing castle. Or, the user can create a Castle. To join an existing castle, you must know the login credentials of an administrator account already part of the castle. Only non-blank passwords can grant access. This helps ensure only authorized computers join the castle (use of strong passwords for administrator accounts is highly recommended). When a computer joins a castle, the accounts on that computer will be added to the list of accounts accessible from any computer in the castle. User specific data (e.g. their password, access rights, and preferences) will be replicated on each computer in the castle and kept in sync. In addition, the newly joined computer will inherit and respect all policies from the Castle.

Information Collected, Processed, or Transmitted:
To help standalone computers find the available castles on the subnet, the machines in the Castle send a broadcast a beacon containing the Castle’s name. Be aware that if you share a subnet with other people (e.g. your neighbor when using a cable modem without a hardware router/firewall) they may be able to see the name of your castles. In this case only choose castle names you are comfortable sharing with others. When joining a castle, the credentials you enter will be sent using security technology (NTLM) to other computers in the castle.

Use of the Information:
Broadcasting the name of each castle makes it easy to discover what castles are available on the subnet. When joining a castle, the credentials help ensure only authorized computers join the castle.

The user must initiate joining a castle using the user interface provided. Whether the user’s computer is able to join a castle depends on whether an administrator of a computer already part of the castle has provided the user with the appropriate credentials. When a castle is formed, a beacon containing the castle name will be broadcast. In this release there is no easy way to disable the beacon. A mechanism to disable the beacon will be added in a future release.

Important Information:
The Internet Connection Firewall (ICF) is enabled by default in this software. Therefore, if you create a Castle, it will send out the beacon, but because ICF is enabled, other computers running this software that have the firewall enabled won’t see the beacon.

If HomeGroup is indeed Castle byte for byte, then what it is basically is the equivalent of an enterprise-grade Active Directory roaming-profile network setup simplified into a wizard dialog with a password field and checkboxes. If it’s not, well, that would be a shame.

From what I understand, Castle was intended to supersede Workgroups which could translate into HomeGroups eventually replacing Workgroups in Windows 7 as well. I think a move most people who’s ever been puzzled by home networking would welcome.

28 insightful thoughts

  1. What’s make me wonder is “User specific data (e.g. their password, access rights, and preferences) will be replicated on each computer in the castle and kept in sync”… If homegroup is indeed castle, will this synchronization takes place on the log-on process ? If yes, they can ditch it now and think about something else…

    Having a roaming profile is really a good thing, and in a business-oriented network the 2 or 3 minutes (that’s the amount of time vista takes to check if my profile is up to date with the server – add a few more minutes if I have changed something – on a 100mbps network) of the login process are acceptable, but on a home machine, the story is quite different.

    So anyone working for this feature on windows 7 : please, please, please make it better than today’s roaming profiles 🙂

  2. It doesn’t necessarily take 2 or 3 minutes. At my current workplace my non-roaming profile takes like 3 seconds to log in, and in a previous environment, my roaming profile took maybe 8 seconds on a terribly slow 10mbps network.

  3. @Travis, at the school I go to we have roaming profiles. On a computer where your local profile has already been pulled down, it takes about 3 seconds to log in because credentials are stored on the local machine, as well as all profile info. When you sign in to a computer that you have never used or haven’t used in a very long time, it can take upwards of 30 seconds to build/ update the profile.

  4. Roaming profiles to me are usually pretty quick, I have seen them go upto 1 minute on log off, log on seems usually quicker.

    I hope they are smart enough to integrate Home Server in some way too. If you have one in the home, what a great use!

  5. Pingback: Windows 7 News
  6. HomeGroup is not Castle indeed but is not an improvement to workgroups either is more like something in between…

  7. RyanLM, Cullen, Travis.

    Saying that its always going to be fast is inaccurate. It all depends on the size of the roaming profiles. Sure, for schools and corporate networks you’re going to have a limited profile size to work with (our corporate network has a 100MB profile limit) it’s going to take no more than a minute to download that from scratch, even on a 10Mb network connection… When you’re at home, this is going to be totally different, as most home users (the ones that don’t know about profile size) will save files directly to the profile. Game saves and other program information will be saved in the profile, and on last check, my home profile on XP was in excess of 700MB. On a slow network, that’s going to take lots of time, especially if there are hundreds of users logging in at a similar time.

  8. Since Castle never made it into Windows Vista as originally intended, it would have been nice if Microsoft had backported the HomeGroup functionality from Windows 7 to its predecessor… HomeGroup would have been a nice Windows Ultimate Extra.

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