In military HQs there are functional areas or branches with different roles that work together to provide an effective output. To the military or civilian outsider these roles can be a mysterious and baffling area where confusion reigns. In addition to the strange language used (see here for more details) it can be difficult to understand the well oiled machine. Below is a lay-person's guide to HQ departments.
The functional area that looks after manning and personnel issues. They move and track who is where. They use an arcane and complex system called JPA (short for Badly Procured Shitshow) that does not work. To maintain situational awareness, the J1 staff regularly decide that the system built by their predecessors is rubbish and they will rebuild it properly. This invariably leads to data loss and everyone in the formation being asked for every single personal detail to be re-declared and input into a PC. J1 is where dinosaurs go to die.
This is where the wannabe 007s work. They pretend to be running vast networks of informants, highly technical and secret surveillance tools or trying to turn enemy spies. In reality they spend their days endlessly trawling social media and making PowerPoint slides. If challenged on any output, they suggest "this is a 'need to know' item" or "you are not cleared for this". These translate to "I do not know" and "I made this up" respectively. To maintain situational awareness, the J2 staff regularly decide that the system built by their predecessors is rubbish and they will re-build it properly. J2 is populated by Int Corps Corporals claiming they are Infantry Captain equivalents.
Use of phrase "Ops" means you can prioritise anything you want. J3 is the place for the little stars to start to shine, and as time is short they will absolutely not touch anything that is "not on the Comd's Radar". If they cannot brief the Comd on their awesomeness, they will not do it. J3 hates J5 with a passion. J3 staff decide on a weekly basis that the system built by their predecessors is rubbish and they will re-build it properly, but they wreck it and lose all the data. J3 is where the ruthless sharks hunt, if you cannot lie and claim "top, top third status" then go home.
It is bipolar environment run by two extremes, either grumpy smelly LEs who hate everyone or terrified young Logistic Officers who cannot wait to escape back to Regimental Duty with any RLC unit. The LE will just say "No!" to everything, unless the Commander personally tells them to do it, they then roll their eyes, make a fuss that they are pulling all the stops out and just do whatever minor & trivial task they were supposed to. J4 staff regularly decide that the system built by their predecessors is rubbish but they are too dense to change it. J4 is where they wear slippers & plot revenge.
This is where they put the bright young things with potential, however they are as mad as a box of barking frogs and cannot understand consequences. Clever young people who have no sanction for failure and time on their hands never ends well. They make up mad stuff involving Millennium Falcons, Jet-ski Ninjas and Snow-speeders with ATGM fitted. Does not matter how bizarre or ridiculous it is, they will still plan it as it is J3 that must enact their madness. If J3 object, then J5 declare a J5/3 airgap and "we Plan not Execute". J5 staff regularly decide that the system built by their predecessors is pretty good but they change it to make J3 look stupid. J5 is where mischievous imps live.
This is a pool of underused talent that desperately wants to be somewhere else. Due to odd personality traits and poor hygiene, the J6 staff are ignored by all other staff both in work and socially. The only reason they are even noticed is that they show up at various meetings so the COS or Comd can berate them for "Comms being down", whilst this is rarely the case and is invariably due to J3/J5 staff skipping ComBAT PT, nobody cares. J6 staff never decide that the system built by their predecessors is rubbish. J6 is where the clever beautiful people go to learn that going outside Stafford area is a bad thing.
This is where they put PTIs when they commission them. They are utterly bemused by this environment and try and get all the fat lazy J1, J2 & J6 staff out running 3 times a day. After a few months they will work out how to turn the computer on and will spend an hour or two not in the gym & instead booking all the LEs and WOs on Prince 2 courses. The J7 staff do not know what system they have but as it can be used to book Prince 2 courses their predecessors were cool dudes. J7 is where there are lots of mirrors for preening.
The military find the most humourless officer they can and let them run J8. J8 makes J4 look generous. It is preferable to have a civilian running this branch, however, they must be retired military to have the required impotent rage. J8 staff regularly decide that the system built by their predecessors is rubbish and they will re-build it properly. They then build an entirely bespoke system based on MS Access and Excel that is crap and nobody understands. J8 is where the embezzlers waiting to be caught hide out.
J9 is where they put all the spivs & wide-boys. Their role is to engage with civilians and apologise. All the lying breaks them down and they turn to self loathing and attacking other staff. Eventually it gets too much and they go work for an NGO, on a Commune or running an organised crime gang. J9 staff do not have a system. J9 is where sad people go.
Comd. The Commander is the boss. Regardless of formation he/she will have been J3 ninja and a COS. They know most of the tricks.
COS. Chief of Staff. Does all the work. Gets the blame. Allowed to shout at anyone but the Comd. Smarter than everyone less the Chief J6 but can still con or threaten them. Will be Comd one day assuming they do not mess up in next few jobs.
DCOS. Deputy COS. Is the only friend of the COS but secretly loathes them. Not allowed to task J2, J3, J5 or J6. Goes out drinking with the J1 & J4 LEs.
HQ SM. HQ Sergeant Major. Rapidly works out he can shout at Colonels and below as he has Comd's ear. Spends hours crying in his office that he is stuck cat-herding a bunch of Officers whilst his mate got to be RSM. Guaranteed to be commissioned and work in J7 or J4.
YofS and Int WO. Yeoman of Signals and Intelligence Warrant Officer. Two, long in the tooth WOs, used as unofficial enforcers by COS/Comd to go spy on Staff, problem solve and "keep a lid on it".
Hopefully this short explanation of the key roles and their interactions provided an insight into the complex nuances of a military HQ?
How do they do this stuff in a Battlegroup HQ?