163

(I got the feeling I've answered this already once, but can't find it) (Also, this is meant as an overview to see development, not about any firsts, inventions or alike) TL;DR: Computer keyboards grew out of calculator key assignments, as both are business tools. The telephone keypad arrangement was derivated in an UI analysis in 1959/60 with 'average' ...


114

Why is ASCII this way? First of all, there is no one best sorting order for everything. For example, should UPPER or lower case be first? Should numbers be before or after letters? Too many choices, and no way to please everyone. So they came up with specific pieces that "made sense": Numerals 0x30–0x39 - Easy bit mask to get your integer value. ...


72

Keyboards have an asterisk because typewriters did, long before computers existed. Typewriters, particularly mechanical ones, typically made a number of compromises to reduce the number of keys required. For example, many didn‘t have 0 or 1, and people used O and I or l instead. Likewise, × wasn’t needed since x could be used instead, or · (. half-up). The ...


65

It all dates back to typewriters, but the two layouts aren’t ASCII v. non-ASCII, they’re mechanical v. electric. The !" etc. layout was common on mechanical typewriters, based on the layout used for the Remington No. 2 in 1878. This is the layout that ASCII was based on; that’s why “!”, “"” etc. received consecutive encodings, aligned with the encodings of ...


63

Computer terminal keyboards needed to reproduce the symbols available on punched cards and paper tape. In the US, punched cards dominated the data-processing industry (communications uses tended to paper tape). IBM punched card codes in particular were significant in the industry. The IBM 026 keypunch (and its replacement the 029) had an asterisk. By the ...


61

According to ASA X3.4-1963 Appendix A, one of the design considerations was: (7) Ease in the identification of classes of characters Furthermore: A4.4 The character set was structured to enable the easy identification of classes of graphics and controls. And on page 8: A6.3 To simplify the design of typewriter-like devices, it is desirable that ...


52

While general purpose function keys are something that had already been introduced in the 60s by manufacturers like Friden (Flexowriter, 1965) or HP (9810A, 1971), it wasn't until IBM's 3270 that function keys were widely available. 3270 terminals are block-orientated, which means all keystrokes, thus all editing, are local. Only the whole screen can be sent ...


51

Even though the CR usually goes before the LF in ASCII text, most printer mechanisms actually perform the LF before, or during, the CR. So the shape of the arrow is actually accurate. This is even true of mechanical typewriters, in which the carriage is returned through a physical lever which, before enough force is transmitted through it to move the ...


48

Given your computer’s vintage, I’m going to guess that the reason there’s a single PS/2 port, intended for use with a mouse, is that its keyboard port is a 5-pin DIN connector as used in the IBM PC AT and its descendants. This was quite a common setup in the mid- to late nineties — most socket 7 motherboards were AT boards and included these two ports (I ...


47

Why is the clock frequency of the PS/2 keyboard protocol so high? I wouldn't call it high. It's quite in line with similar keyboard speeds - like Amiga operating a 17 kHz. At 11 bits per scancode, 10 kHz is a massive 909 scancodes per second. World-record holder Barbara Blackburn peaked at 216 wpm ≈ 18 cps ≈ 54 scancodes/sec. on a Dvorak keyboard layout. ...


41

The ← and ↑ symbols were originally included in ASCII-1963 as programming operators. They were used in a number of programming languages at the time, but the only common usage left today is in Smalltalk where the _ and ^ characters which replaced them in ASCII-1967 can still be used for variable assignments and variable selectors, respectively. The ...


40

The Space Cadet is a keyboard designed for use with Symbolics' Lisp Machines, and many of the extra keys are specific to that use. Starting from the bottom row: Hyper, Super, Meta and Ctrl are modifier keys, known as bucky keys; they are equivalent in use to the Ctrl, Alt and Alt Gr on modern keyboards (and to the Windows, context menu, Apple and Option ...


40

I remember a conversation with an IBM engineer back in the 1980s, who implied there was an internal fight over this between IBM's engineering and marketing departments. The engineers wanted the PC to have the same keyboard as the popular 3270 mainframe terminal, for easy migration of users and software in a business environment, and in fact IBM did produce ...


39

Before IBM PC even existed, terminal keyboards for IBM Mainframes make extensive use of the SysRq or (System Request) key. I recall using SysReq key on IBM 5251 and 5291 terminals for IBM S/36. Probably the key (and function) was already present in the 1970s IBM 3270 terminal. Its function was to suspend the current job and display the System Request Menu. ...


38

Chromatix answer already perfectly nails the technical background. Especially the reference to classic typewriter mechanics, predating any TTY or terminal, were the symbol used quite closely follows the hand movement when isueing a new line. Historically it may be interesting to look at the development. The combined function as a single key was only ...


35

The Restore key triggered the NMI (non-maskable interrupt) line; to actually have an effect it had to be combined with Run/Stop - it would soft-reset the machine (via an indirect jump vector that could be overwritten to a custom routine if desired. This wouldn't reset memory, but would stop even misbehaving programs in most cases.) Run/Stop was two keys; ...


35

The two sets of numbers serve different purposes, and I realise not all keyboards have the NumPad is an important factor. The main part of the keyboard is based on typewriters, and has to provide everything required for text entry, on its own. This means that it has to include digits (including 0 and 1, which many typewriters didn’t). Typists will tend to ...


28

SysRq is popular because the PC AT was popular, and its clones were too. PC clone manufacturers copied all the features of the computers they were cloning, with the exception of BASIC in ROM, and that included SysRq — both the physical key, and its associated handling in ROM (interrupt 0x15 function 0x85). Any OS or software running on the AT could end up ...


28

The official answer (at https://support.apple.com/kb/TA34988?locale=en_US) is that they pretty much made it up as they went along: At some time in Apple's history it was decided to put the "bumps" on the D and K keys while some other computer companies use the F and J keys. [...] Apple engineering has indicated there is no standard, such as ISO or ANSI ...


27

man 7 ascii of Linux Programmer's Manual says, Uppercase and lowercase characters differ by just one bit and the ASCII character 2 differs from the double quote by just one bit, too. That made it much easier to encode characters mechanically or with a non microcontroller-based electronic keyboard and that pairing was found on old teletypes. As ...


26

I did such interface long time ago. It was(is) an internal interface designed to fit in a place near the right side of the board when using the Plus case. Technical details here: http://www.zxprojects.com/index.php/ps2-adapter This is the board Designed to fit here: Schematic. Very simple. One microcontroller does all the work. Upon booting, the uC ...


25

In scancode set 2, the "break" scancodes consist of the "make" scancodes prefixed by F0. This is consistent across nearly all the keys. Some keys include a modifier prefix in the Ex range as well, and this is repeated in the "break" sequence. Additionally some keys behave as if two keys are pressed at once, and thus include multiple F0 codes to ensure ...


25

The user will perceive a delay (latency) between pressing a key and seeing the computer react. The reactions are usually on its screen, such as displaying a typed character or motion in a game. This delay must be kept short for the user to have a feeling of sharpness in the computer's reactions. The delay is the sum of (a) the keyboard scanning interval and ...


24

Early Wang basic computers used a backplane keyboard with an enormous bespoke parallel interface to the detached style keyboard device. Wang's 2200 and 2600 BASIC-only minicomputers were available with the 2215 BASIC keyword KBD, the 2222 alphanumeric typewriter KBD, and the 2223 upper/lower case BASIC keyword KBD. None of these keyboards contained a key ...


23

Personally I know this from a typewriter course in school (ca. 1973). The machines we used hat slightly different cavity on D/K to support touch-typing. we were supposed always rest our middle fingers there while having the rest afloat. A similar lesson was given for the use of adding machines with a similar keycap for the 5 key. But so far I couldn't find ...


23

Of the variants produced in a relatively large series - let me remind you about the keyboard connection on the Commodore 128D - it was connected using a 25-pin interface, 23 lines of which directly represented the matrix of keys.


22

I think the answer is Lotus 1-2-3. Working in a spreadsheet, you are going to want to be able to use the numeric keypad for quick numeric entry, and you are going to need to use the cursor keys to move around the spreadsheet. Having to continually hit the Num Lock to switch between "modes" would be a pain. I have no actual evidence to back this up, other ...


21

Keyboard Switch On the International version Apple IIc the keyboard switch swiched between a country-specific layout and and a standard U.S. layout. On the USA version it switches between the standard QWERTY and a Dvorak layout. (This was not so much a desired feature as a side effect of having to build the European version with a keyboard switch; putting a ...


19

In the end, I decided that it had to be easier to take the keyboard apart than to de-solder the 4051's and so I carefully removed the 18 tiny screws from the back of the keyboard. It wasn't nearly as bad as I expected (I was concerned that I was going to have springs everywhere). After disassembly I fired up the Atari to try and see if I could get the A ...


18

The ← and ↑ symbols are remnants of an earlier version of ASCII. The ← and ↑ have now been replaced with _ and ^ respectively.


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