OP:
This is nothing but the standard nonsense....
All internal active implants have DNI. The 4 listed are the only ways to get external access to DNI though... internal commlink has direct access... Trodes + sim module... or datajack.
DNI is nothing but the bodies nervous system. It's a transmission path. It's like an ethernet cable... on it's own it doesn't do anything... but the brain on one side and the cyber on the other somehow learn to talk directly to each other and operate. That's why the external access port provided by the above is important... without them nothing outside the body could ever get into the DNI network.
This is no different than skinlink provides an alternate way to wire two things together. It's the physical layer on which the network runs.. DNI == nerves, Skinlink == skin, RF == wireless signal rating. You get onto each by a different method.
This isn't quite accurate. Wireless and Skinlink are just means of data transmission, using radio waves or the electrical conductivity of the skin respectively. DNI is more than that, it doesn't just transmit and receive data along the nervous system, it translates that data into a form that the brain can understand and vice versa. Only Technomancers can actually think in machine code, everyone else needs DNI.
Think of it like connecting a Blu-Ray player to an old CRT TV. Something has to translate between digital and analog and back for them to communicate. That is the DNI.
As for the rest... hacking cyberware is a non-shadowrun trope that some people insist on trying to force into the setting no matter how badly it fits. Normally based on stuff like Ghost in the Shell where almost everyone including the non-cyborgs have had their brains turned into AI's... then the AI's installed into fully drone bodies. While in SR cyber is not a pure metal solution... it has both meat and metal parts to make it work. I'll repeat that.. they've had their consciousness transformed into AI's. The exact opposite of shadowrun.
It also relies on a completely flawed analogy that cyberlimbs are drones. They're not... they don't have sensor ratings or a slew of other drone attributes. Even if you granted that a limb could... it would have no way of letting you know what it was doing or where it was pointed in the case of a gun.
You don't 'rig' your cyberarms (plural). You can only jump-in to a single drone at a single time. Yet you seamlessly can control all the individual parts of a full cyberbody without any kind of problems. You don't have a matrix icon present in a cyberlimb which the hacker can attack as if you were a rigger in a drone either.
I agree. Cyberware hacking doesn't belong in SR. It is an idea that seems to have been added late in the process and it has never been fully explained or integrated into the rest of the system.
To clarify Falconer's statement for anyone who hasn't seen Ghost in the Shell, in that setting most people have had their physical brain replaced by a computer (the "Shell") that they have uploaded their consciousness and soul into (the "Ghost"). This is the most common cyberenhancement in the setting, often possessed by individuals that have no other cyberware at all. All additional cyberware requires a cyberbrain and is controlled like a rigged drone, requiring concious operation. There is no Essence loss, because your "Ghost" (soul, spirit, Essence, whatever) is uploaded into your Cyberbrain along with your mind, and is the only difference between a clone or robot, and a fully cybered human. If a hacker can get into someone's cyberbrain, they can control their cyberware, or if they're good enough even hack the victim's memories, personality, vision (Laughing Man), or even their Ghost (Puppet Master). All of this works because the cyberbrain is a digital device that is able to directly communicate with other digital devices. It makes everyone a Technomancer.
In SR, things work very differently. Even a full conversion cyborg (Jarhead) still has to have a meat brain, and that brain cannot be hacked directly because it doesn't communicate in the same language that machines do. Other than those individuals, no one else rigs their cyberlimbs because they don't need to. That is what the DNI accomplishes, translating biological "brain code" into machine code and back again at the point of connection, but the biological nervous system is not a computer network. You can't send a signal into a nerves in your arm and have it route to the nerves in your leg. Nerve signals don't just pass through the brain like a router, and anything on the biological side of the DNI cannot be interacted with except through a DNI.
TL;DR - cyberware hacking makes sense in Ghost in the Shell, and doesn't in Shadowrun.
As for the rest... there's no good reason whatsoever for anything to be wireless it simply doesn't pass the smell test. If I'm at the local street doc to get my cyber checked up... he doesn't need wireless... all he needs to do is slap a helmet on me with a trode net to a cheap sim module and he can do the diagnostics easily enough. It's nothing other than the 'everything is wireless' mistake that SR4 made to be taken to an absurd degree.
Toss in wireless nanites... and the whole thing goes even worse... as they can turn on anything wireless which has been turned off. Or even provide wireless themselves. It removes any semblance whatsoever to those other setting tropes... where it's possible to turn off all outside connections at will (GitS this is referred to as autistic mode).
The wireless nanites don't make any sense at all to me. I can understand that they can provide a wireless signal, but how would that help hack into something that has has its wireless interface removed? If the computer in the device doesn't have the software or hardware required to send or receive wireless transmissions, that would be like connecting a wireless networking adapter to a modern computer but not installing the driver for it. The computer would technically be wireless, and could be detected and even connected to wirelessly, but there would be no way to do anything over that wireless link because the computer can't communicate with the wireless adapter.
Basically they exist for the sole purpose of being a "Fuck you" to runners who make a tactical decision to sacrifice the convenience of wireless in favor of security.
Normally based on stuff like Ghost in the Shell where almost everyone including the non-cyborgs have had their brains turned into AI's
http://ghostintheshell.wikia.com/wiki/Cyberbrain
For reference. It's not unlike the headware and cranial containment units SR has already, until you get to the extremes. (and let's face it, the books don't cover the furthest extremes of the SR setting)
As stated, it is entirely unline headware and cranial containment, as it involves actually replacing the meat brain with a computer that somehow runs your mind
and soul as software.
