What does the C in Cid stand for in winDbg, kdbg and livekd?

Question

If execute the !process command in the windwos debugger you get output in this format:

PROCESS fffffa8006bff940
    SessionId: 0  Cid: 03ec    Peb: 7f79ae1f000  ParentCid: 02e4
    DirBase: 084ed000  ObjectTable: fffff8a002c3fd80  HandleCount: <Data Not Accessible>
    Image: svchost.exe

It's well documented that Cid is the ProcessId (pid) in hex. However, I don't see what the C stands for.

Answer 1

It stands for CLIENT_ID.

From this MSDN blog post (emphasis mine):

Recently someone asked me what was the real meaning of the ‘Cid’ field which appears in the output of commands such as !process and !thread in the kernel debugger (kd). Though from a practical perspective I was aware that these represent the Process ID and Thread ID, I was unsure of what Cid stands for. In course of a search, I found a public source which answers the question. Cid is short for CLIENT_ID which in turn is an undocumented structure.

That posts cites that the original source as Undocumented Windows 2000 Secrets: A Programmer's Cookbook, by Sven B. Schreiber.

Answer 2

03ec = 1004 in dec. 'c' is a last hexidecimal digit of that number, it doesn't stand for anything (well, 12dec by itself).

the cid/pid is a 4 digit hex value, not 3.