The Model F Hybrid Keyboard – the rarest IBM keyboard?

This week, it seems it’s ya Detective Shark here trying to find out more information about a particular IBM keyboard that came to my attention last week. Subsequently, I am on a hunt for it.

It’s ya Detective Shark here this week trying to discover more information about a particular IBM keyboard that came to my attention last week. I am on the hunt for more information about it, but I have pieced together something worth a read. So, here is it:

This was originally going top the second-edition seven interesting keyboards list due this week to contrast the well-known M15 Adjustable Keyboard from last week, but what I want to say about this keyboard became too much for a post that features information about six other keyboards. So…


IBM System 9001 (left) and 9002 (right)

I came across this mysterious keyboard on a three-year-old Deskthority post by Engicoder (2016) about an advert for IBM System 9000. The System 9000 was a family of IBM Instruments laboratory computers introduced in 1982, and eventually consisting of the 9001 benchtop computer (pictured left), 9002 desktop computer (pictured right), and the unpictured 9003 factory computer. The System 9000 was an upmarket 16-bit/32-bit Motorola 68000-based microcomputer developed before but launched after the legendary but effectively inferior 8-bit Intel 8088 powered IBM Personal Computer (5150). Columbia University (2019) has a good and more detailed overview about the System 9000 in case you’re interested, and the full advert for the IBM System 9001 and 9002 was found via archive ( “The Enhanced IBM System 9000…”, 1984).

From a visual inspection, both the “Standard Keyboard” and this special “Hybrid Keyboard” behemoth are clearly Model F XT variants. In Model F family tree terms, the Standard Keyboard would be the third deployment of the original XT design. For context, 1982 also saw the first diversification of the Model F design with the Beamspring-replacing 84-key IBM Displaywriter Keyboard (P/N 2684674) which future ‘big-guns’ terminal Model Fs such the Command Key Keyboards “Battleship” and “Unsaver” derived from. 1984’s Hybrid Keyboard would be the fourth deployment of the Model F XT layout alongside the IBM “Bigfoot” 5291 Display Station Keyboard Unit (P/N 4176191). But by 1984, the Model F family had become fully diverse, with the Model F AT, Battleships, Unsavers, 3101 “Blue Switch-less” (as Chyrosran22 puts it) Beamspring Replacements, and the “Blue Switch” family now present and the “zero-generation” Model Ms were only a year away. The fifth and presumed final deployment of the Model F XT layout and the last new Model F family design was 1987’s IBM EMR Keyboard II, after which the Model M family assumed the position of IBM’s flagship keyboard family.

But first, a little bit about the Standard Keyboard

It seems this keyboard is relatively well documented and confirmed to be a Model F XT underneath, and the Columbia University overview confirms it to be a “regular PC keyboard”. The announcement letter from IBM (1984) for the 9002 states this keyboard’s part number to be 4780898. As far as I can tell, the IBM System 9000 Standard Keyboard was its official name. Deskthority (2018) has a wiki page about this keyboard.

Being a Model F XT, you can assume it to be a solid keyboard with a now-archaic layout. Should you encounter one for a fair price, it might be worth investing in one of these rare keyboards! Information is still quite limited with only a few examples documented in recent times, but just one of the standard keyboard encounters shed more information than what’s collectively known about the hybrid keyboard.

Speaking of which…

As far as I could tell, the aforementioned announcement letter from 1984 is the earliest available reference to the hybrid keyboard. In it, the keyboard is stated to be brand new and integrates a “functional keypad”, which contrasts the previous offering of a standard keyboard with a separate “General Purpose Keypad” that can be seen in Columbia University’s overview (referred to as a “touch panel”) and came with an overlay to provide the legends for the keypad. This overlay is included with hybrid keyboard, which means in both cases the functional keypad was likely reprogrammable otherwise they might as well have just printed the legends onto the keypad. The apparent lack of physical keys and the fact that original discrete keypad was referred to as a touch panel means it was likely a pure membrane pad, and you could probably write on it since it looks pretty whiteboard-esque. From here on, I’ll be referring to the main Model F XT keys as the main block and the functional keypad as the membrane block.

The keyboard’s build looks quite formidable, and I wouldn’t be surprised if the design was derived from the also 1984-launched Model F Command Key Keyboards. In fact, the hybrid keyboard bears a striking resemblance to the 104-key “Unsaver” variant of the CKK, but the 24 command keys elevated above the main block have been replaced with three rows of 19 membrane pads. Combined with the 83 keys in the main block, the hybrid keyboard bears 140 keys total! That surpasses all known Beamsprings, Model Fs, and Model Ms. Outside IBM, keyboards that have this amount of keys are usually far larger than the hybrid keyboard and typically nicknamed “aircraft carriers”.

So, what do we actually know?

It is probable that the hybrid keyboard is a derivative of the Unsaver CKK, featuring a standard IBM XT layout keyboard with a 57-key membrane growth grafted to it. Given that the well-documented IBM System 9000 Standard Keyboard speaks traditional Set 1/XT, it is likely this keyboard does too thus adapting it work with modern systems could easily be done with Soarer’s. The membrane block was most likely reprogrammable through software (to suit different lab environments), and

And finally. Considering this is uncharted territory, I’m very much seeking more information about this keyboard. So if you happen to know anything more about this keyboard or in the best case own one, please get into contact with me! In keeping with the nicknaming prevalent in the keyboard community, we should name it RIGHT HERE! My vote goes to “escort carrier” since it’s membrane block looks like a small flight deck. Like how actual escort carriers are far smaller than normal aircraft carriers and even ships like battleships and battlecruisers, the analogy fits here since the hybrid keyboard is quite a bit smaller than a Model F/Model M “Battleship” CKK (eg. P/N 1390886) or Model M “Battlecruiser” Revised CKK (eg. P/N 1394324).


2 thoughts on “The Model F Hybrid Keyboard – the rarest IBM keyboard?

    1. I see what you mean! IBM themselves used PC type keyboards for a lot of their terminals, word processors, and even electronic typewriters in the 1980s – in fact most of IBM’s Wheelwriter typewriters (their last typewriter series) use integrated Model M keyboards as the input device!

      Yes! The grid part is the membrane block, and in practise you’d put an laminated overlay on top to give it some legends. Imagine it to be a primitive capacitive touch screen without an LCD or LED panel under it.


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