A Service Group is a collection of similar services that are loaded
together at startup. Most services that appear in the
HKEY_LOCAL_MACHINE\CurrentControlSet\Services subkey are part of a
Service Group. Windows NT loads one Service Group at a time. Services
that are not in a group are loaded after all Service Groups are
loaded.
The HKEY_LOCAL_MACHINE\CurrentControlSet\Control\ServiceGroupOrder
subkey determines the order in which Service Groups are loaded. The
List value is a REG_MULT_SZ entry that specifies the Service Group
order.
The HKEY_LOCAL_MACHINE\CurrentControlSet\Control\GroupOrderList subkey
determines the order in which services within a Service Group are
loaded. Services in a Service Group are assigned a tag, a unique
numeric value within a Service Group which determines the service load
order. Each value entry in GroupOrderList represents a Service Group.
The value of the entry is a series of tags in a specified order. The
first entry in this REG_BINARY value is the number of services in the
group, followed by the tags in load sequence. If you look at
PointerPort you can see that there are 3 services in the group and
that the service with tag 02 is loaded first, followed by the service
with tag 01 and then tag 03.
At a service level, the
HKEY_LOCAL_MACHINE\CurrentControlSet\Services\ServiceName subkeys
contain:
Group - this REG_SZ specifies the Service Group name
that a service belongs to.
tag - this REG_DWORD specifies the service load sequence.
DependOnGroup - this REG_MULTI_SZ entry defines the Service Groups which must be loaded
succesfully before this service loads.
DependOnService - this REG_MULTI_SZ entry defines services that must be loaded successfully before this service loads.
Interestingly enough, Black Viper doesn't seem to have such a definitive list (though you can click the individual services to see their dependencies–which may be faster than waiting for the Service snap-in to do whatever it is that it does that takes it several seconds to populate the dependency tab). Maybe contact Black Viper to add a chart…
– Synetech – 2012-07-13T18:18:29.713@Synetech This is a great start! Though, not sure how nicely dependcies will fit into his chart given the one-to-many relationships of services. Still, might be worth bothering him. – Chad Harrison – 2012-07-13T18:22:57.523
1I was thinking of a separate graph as opposed to the main chart. Hmm, I haven't used GraphVis in a while… – Synetech – 2012-07-13T18:56:54.753