I have gathered a sample of the common questions people have about IBM and co keyboards when they are starting out in the hobby (or are just curious) and have attempted to answer them in detail and logic. A lot of these can be subjective though, so other people may give you different answers.
Are Model Fs better than Model Ms?
Yes and no. In terms of the core technology inside the keyboards, the buckling springs, the Model F's capacitive implementation is more advantageous - it has inherent NKRO and a much higher expected lifetime. Subjectively, some people may also prefer the higher-pitched auditory feedback and lighter feeling of the switches too. Model Fs tend to be housed in harder (but also more brittle) plastic casing or even metal casing, and the switches are backed by thick steel plating, resulting in very taut keyboards. The biggest downside of the Model Fs are their layouts (especially for ANSI users), which are largely archaic by today's standards. If you are an ANSI layout user, the most common Model Fs will be a polarising contrast to what you are used to and are standard with Model Ms. If you are an ISO layout user, the 122-key Model F is very similar to the ISO layout cemented by the Model Ms and the Model F/AT is not too dissimilar either. Model Fs are also very much more expensive and rarer than their equivalent Model M counterparts.
Are Model Ms "mechanical" keyboards?
Unfortunately, the answer is complicated due to two reasons; the Model M is a huge family of different types of keyboards, and the fact that the definition for "mechanical" is not properly defined. Assuming the Model M in question is a standard IBM Enhanced Keyboard, based on common points that people define by; they could be mechanical since they have part-way actuation, use a coil spring of some sort and are simply not rubber dome switches, but they could also not be mechanical due to the membrane sensing circuit and the fact it does not have NKRO. In reality, "mechanical" is a non-standard marketing term with a loose definition that is based on the subjective opinions of enthusiasts, meaning using the term is only really useful for insinuating a high-end keyboard - which Model Ms were and are still today - regardless of most of its technical specifications. Anyway, membrane and NKRO points could be rebutted too - compared to the Model F's capacitive buckling spring, the sensing circuit is the only major design difference but how the switch works, clicks, and provides feedback is still exactly the same. Also, what stops people from arguing that the limitation of the USB interface on some other keyboards downgrades them to non-mechanical because they can only reach 6 to 10 KRO?
Are Model Ms better than Model Fs?
Yes and no. The chief advantage that Model Ms have over Model Fs are their ANSI and ISO layouts, which with the addition of GUI keys from the mid-'90s are still the standard PC layouts used today. This was in fact used as a selling point of the Model M over other keyboards, hence being called the IBM Enhanced Keyboard. The success of the machines they were bundled with or made available for as an option propelled the Model M to prominence and thus many examples are still in circulation and prices are more reasonable than Model F alternatives. Under the hood, however, Model Ms were essentially a cheaper evolution of the Model F design; the capacitive assemblies were replaced with membranes, the steel backplates were incrementally decreased in thickness over the decades, and how the keyboard assemblies are held together was changed into a more imperfect solution of plastic rivets.
Can I use Model Ms for gaming?
Absolutely, with some considerating in mind. Model Ms have the reputation of being more of a typing instrument than a gaming peripheral due to 2KRO and high actuation force requirement. Starting with 2KRO, in practice, 3 or 4 simultaneous keystrokes will be registered depending on the location of all the keys being pressed - for example, if you were playing a first-person shooter game, you can press W+A or W+D to move, press G to throw a grenade, and press a modifier key together and all will be registered. Secondly, it is true that the required force can be an issue for people used to light switches and thus could tiresome people's fingers when rapid pressing is required in a game, so consider buying a membrane buckling springs key switch tester if this is a concern to you before buying a Model M keyboard outright.
How much should I be concerned about failing plastic rivets on a Model M?
On average, it should not be a huge concern since plenty of people buy and sell Model Ms that have yet to be bolt-modded and never experience issues after long transits. For brand new Unicomp Model Ms, you probably will not have any such issue for at least a decade provided you take good care of it. The most likely Model Ms to be suffering such catastrophic plastic rivet failure are ones that are so old that the plastic itself is being to degrade, those that come from industrial use, and those that come from areas of the world with inhospitable climates.
I want to use my vintage PS/2 keyboard with a modern PC - how?
Converters for PS/2 to USB keyboards are plentiful, but you will need to be vigilant in regards to the type you need. Both passive adapters and active converters exist, with passive adapters simply being a pin swap between the two types of connectors for more modern PS/2 keyboards that also support USB protocol internally. Your '80s Model M, for example, cannot do this, so what you need is an active converter. As a rule of thumb, active converters are specifically labelled as such, sometimes described as having a USB integrated controller (IC), feature a small box in the middle of the cable, and more often than not include both keyboard and mouse PS/2 ports together. Exceptions to this exist, however, so be sure to check out reviews and ask the manufacturer to clarify.
What screwdriver do I use to open up my Model M with?
For mainstream buckling springs and Quiet Touch Model Ms, you are looking for a 5.5mm (7/32") nut driver. They can be had for just under £5 off eBay as of 2020. They are typically sold as being for Vruzend battery kits and for bicycles.
What's the difference between a passive adapter and an active converter?
The key is in the noun that passive or active is paired with. Whilst many may use the words adapter and converter interchangeably, there is a technical difference and the best way to look at it is as follows: an adapter adapts between two or more given physical interfaces, and a converter converts a between two or more given signals and possibly adapts the physical interface at the same time. With this in mind, a passive adapter simply changes one physical interface to another without modifying the electrical signals - for example, an AT to PS/2 adapter would be considered passive since both use the same underlying protocol and only the physical connectors are different. By contrast, an active converter processes the data running between the keyboard and host computer with an integrated circuit for the purpose of transforming one protocol into another - for example, a Soarer's Converter would be considered active since it converts the Set 1/XT, Set 2/AT or Set 3/terminal scancodes of the keyboard into USB HID scancodes.