I've read that the "F-16", without it being specified what version, uses the 1750A CPU, it is on the list here, although without a citation: https://en.wikipedia.org/wiki/MIL-STD-1750A

However, surely this can't be right for more modern F-16's?

I'm curious what CPU the F-16A, C, E, and IN uses.

Perhaps even the more modern F-16's still retain the 1750A for some "legacy" features, but have a more modern "front end" CPU to handle the more modern features?

  • $\begingroup$ Not clear what you are asking here. A system of that size could easily have more than one CPU per subsystem. You can safely assume fly-by-wire has 2-3 CPUs different from the auto pilot. 1750A you mentioned was used by flight control and fire control, while the answer below listed MIPS family for mission control. They may co-exist on one aircraft easily. $\endgroup$ – user3528438 Jun 22 '18 at 2:46
  • $\begingroup$ @user3528438 Good point, I completely overlooked the other subsystems. In my mind, the mission computers constituted the 'brains' of the aircraft, but it's an incomplete picture. I guess I should clarify the answer. $\endgroup$ – aerobot Jun 22 '18 at 3:16
  • $\begingroup$ The F-16 was designed in the 1970s, so expect 1970s technology in the oldest of them. Of course many of them will have been upgraded over the 4 decades since they entered service. $\endgroup$ – jwenting Jun 22 '18 at 4:48
  • $\begingroup$ airplanes' computer's architecture may be different from your desktop computer. It may be based on specialized chipsets (real time constraints, specialized computation,...) I'm not quite sure you ca n compare it by only focusing on CPUs. $\endgroup$ – Manu H Jun 22 '18 at 7:24
  • $\begingroup$ @jwenting: The F-16 received a mid-life update (from Block 50 on, IIRC) because the additional load of terrain avoidance made new processors necessary. First flight was even before the 1750A standard was finished, so a range of processors were/are used. $\endgroup$ – Peter Kämpf Jun 22 '18 at 12:28

MIL-STD-1760A is simply the standard that a processor must conform to, and is not an actual model of CPU.

There are actually a lot of independent computers in a military aircraft, each with specific responsibilities. They are usually linked up via networks, typically over MIL-STD-1553 busses for older platforms. The radar has its own processor(s) and architecture(s), as does the flight control module, the fire control module, the navigation system, the munition controllers (sometimes one per weapon station/pylon), the display controller, the mission computer, et cetera. All of these come from different OEMs, and therefore use a variety of hardware. The different subsystems present and their exact functionalities depend on the design and requirements. A subsystem may itself be composed of multiple computers within their own network, independent of the main aircraft networks.

The F-16 uses Raytheon's Modular Mission Computer (MMC) for its mission computer, with the following specs:

The first generation, the MMC3000 relied on MIPS R3500, a 32-bit chip processors with 110,000 transistors and running at 12 MHz. We found this chip on the end of the 1990s HP9000 computers. The computer had 4 MB of memory RAM.

The MMC5000, the second generation of the F-16 computer, still relied on a chip MIPS, a RM5260 who was noticeably faster (with a 133 MHz to 150 MHz clock frequency) and above all it is a 64-bit chip. The memory was more than doubled, with 10 MB available.

The MMC7000 that equips the more modern F-16, including all F-16 Europeans who benefited from the MLU (mid-life Update) modernisation, has always that 10 MB of memory but its RM7000A processor, designed in the early 2000s, works between 300 and 400 MHz.

Source: http://www.4erevolution.com/en/ordinateur-de-bord-f-16/

I highlighted the mission computer because I think of the mission computer/controller/processor (exact terminology depends on the platform) as the brains of a military aircraft. They tend to be the bus controller of the main aircraft network, aggregating inputs from other subsystems and computing/providing information to the pilot to help them carry out their mission.

To the second part of your question, I assume you mean faster or more powerful CPUs when you talk about modern CPUs. Modern here depends on context. CPUs used In aircraft will never need the type of clock speeds or memory capacity you see in consumer computers, for a few reasons. Firstly, there is actually a lot of processing capacity distributed over the various subsystems - the need for a single powerful chip only arises when you demand that a single chip do everything. Secondly, when the requirements of subsystems are as specific as they as in military platforms, the software can be very compact and efficient, unlike consumer software (which require a lot more code for things like architecture adaptors, multi-tasking logic, and thousands of device drivers) - you trade off unnecessary flexibility in return for reliability and efficiency.

The multi-functional displays of military aircraft (and also commercial ones) focus on conveying the necessary information in a clear and concise manner. The rendering requirements are actually quite primitive compared to modern 3D games - it can get by with less processing power than a computer from the 1990s.

EDIT: Elaborated answer, following user3528438's comment.

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    $\begingroup$ I agree with your later point, but think it is worth bringing out for emphasis: a great deal of money and work by very bright and up-to-the-minute people continues to go into making avionics CPUs and other ICs robust and reliable. New, creative and cutting-edge research continues to be applied in their validation, investigating and preventing failures, etc. In no sense is this a field which has been "left behind" or slow to "get with the program". It's the same with medical devices. It's something people often forget (including parachuted CEOs from other sectors, with disastrous results). $\endgroup$ – user29782 Jun 25 '18 at 16:26
  • $\begingroup$ A quibble. MIL-STD-1750A is 16-bit instruction set architecture. MIL-STD-1760 is aircraft/stores interface. $\endgroup$ – John R. Strohm Jun 28 '18 at 17:23

F-16A/B had two computers (not counting the Firecontrol Radar). It used dual Intel 8080 microprocessors for the Stores Management Set Central Interface Unit and Delco M362F (if memory serves me) (proprietary 16-bit) for the Firecontrol Computer, at least through Block 15B. The 8080s were programmed in assembly language. The FCC was programmed in JOVIAL J3B. The Firecontrol Radar was purchased as a unit and GD had nothing to do with the software in it, as far as I know.

F-16C/D had four computers, again not counting the Firecontrol Radar, and used Zilog Z8002 and MIL-STD-1750A through at least Block 30. All were programmed in Jovial J73.

F-16C/D later switched to Raytheon (actual Texas Instruments DSEG) Modular Mission Computers. I do not know what processor(s) the MMC used. They were originally programmed in Ada. I do not know what they are currently using, but C++ would not surprise me.

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