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65

There were a few reasons: Old monitors had very low refresh rates (driven by hardware prices), and green phosphor has the longest afterglow (remains on the screen for the longest time) Green phosphor was the first available for use in monitors (and some sources also say that monitors of this type were physically lighter) It was the brightest type of ...


34

CRTs don't have pixels, they don't work that way. Also, arcade monitors expose all the picture controls at the back so it is possible to adjust them quite extensively. Operators would have made sure that the picture was the right shape and in focus near the edges. Since the controls are all analogue and no-one bothered to measure the display geometry the ...


32

CRT TVs are analog devices, there is no "pixel", but the size of the spot limits the resolution of the image, as the size of silver nitrate crystals limits the resolution of photo films. Several arrangements of the colour stripes on the CRT tubes have been designed, they are a compromise between resolution, luminosity and the precise alignment of the ...


24

ZX Spectrum: has 21 user definable graphics (UDG) available to the user via POKE USR command. Also, main character set can be redirected to RAM (sysvar CHARS, 23606-23607) so it is fully definibled. It doesn't have a real text mode. All text is rendered into pixels by the firmware. Jupiter ACE: has the entire character set in dedicated RAM (but available in ...


23

EHB For example, a game that uses EHB (Extra HalfBrite) mode during the game action (i. e. ingame) is Pinball Dreams. In my example run of the Beat Box table I can find the following in the copper list: $00D6EA WAIT $4211FFFE $00D6EE MOVE #$6200,BPLCON0 I. e. it waits for raster line $42 (66) and uses BPLCON0 to set the number of bitplanes to 6 without ...


22

Why did the original Apple //e have two sets of inverse uppercase characters? Simple: To allow lower case inverse letters. It's all about the clever way Woz arranged the original II's single character set to save in hardware and offer additional functionality. There is only a single character set of 64 characters, showing up 4 times in 256 entry character ...


20

Digital Research produced as one of their early attempts into graphical desktops (on their way to GEM) a basic portable graphics library - GSX. GSX did actually support proportional fonts, both in print and on-screen, and was included with the CP/M support in Amstrad machines running CP/M Plus. GSX was supported by two of DR's own applications, DR Draw and ...


20

Canonically in NTSC standards the drawn lines are tilted slightly so that the start of the odd field starting at the left is perfectly level with the top of the even field starting in the middle horizontally. The actual angle though is so tiny, ~0.09 degrees, that it's negligible compared to the rotation error you'd get just from the earth's magnetic field ...


19

Was CP/M ever used, in practice rather than just as a tech demo, in less than 80 columns? Most prominent here may be the Apple II with Micro- Soft's Softcard. While most users did use it with an additional 80 column card, it also worked well using the basic 40 character display. After all, CP/M itself wasn't tied to any display size or a CRT at all. ...


17

Yes, it is possible. There are a number of ways: If your TV has a SCART connector, you need a cable adapter from DIN 6 to SCART, wired like this (the audio is taken from the audio out using a standard stereo 3.5'' jack): (taken from CPCwiki) If your TV does not have SCART, but composite video input, you must Either use a RGB to CVBS adapter (using for ...


16

The cheapest option is to use the composite output, so it's compatible with any monitor that supports composite but it's only black and white. Or if you have the A520 modulator (about $25 on eBay), you can get a color image through composite, RF (not recommended), or modify the A520 for S-Video. If your TV has a standard definition tuner, you may also be ...


16

IIRC, the electron gun was actually installed in a position where it was rotated slightly relative to the tube, to compensate for this effect, so the scan lines did end up being horizontal.


15

The 8080 is not a microcontroller, but a microprocessor, so it had no special provision for LCD displays, as modern microcontroller may have, except maybe for the ability to use packed BCD numbers. It had no in-built host peripherals that would support protocols like RS232 or SPI. You don't mention what kind of LCD display your college used, so this is only ...


15

Well Cromenco have something on page 2 of this issue of byte. https://archive.org/stream/byte-magazine-1980-11/1980_11_BYTE_05-11_High-Resolution_Graphics#page/n1/mode/2up 756x482 in 16 colors, and on page 70ish there's an article which talks about max raster screen resolutions of 1024x1024. Also worth looking at is the HP9845C with a cost of $39,500 ...


14

Just the first (of many) example of using proportional fonts on Commodore64: https://youtu.be/k2NRlsopoOU?t=441 You couldn't really use a proportional font on the Spectrum because the colour attributes were one background and one foreground for each 8x8 square. That meant that, practically speaking, each letter had to be by itself in an 8x8 cell. ...


13

You're correct; the only interrupts on offer in a Vic-20 are those from a VIA — they're plain old 6522s in the Vic-20, not 6526s. The original VIC chip exposes the current scan line via a couple of registers so instead you'd perform a busy loop until it got to the number you wanted, then cue the VIA. I'm not a C64 expert but besides the lack of hardware ...


13

Did arcade monitors have same pixel aspect ratio as TV sets? Short answer: No, not necessarily. Long Answer: To start with, 'Title Safe Area' is an idea to define the parts of one transmission to be displayed even if any of the many receivers is maladjusted. It's nothing inherent to the TV signal or its definition, it's a safeguard against less than ...


12

The TI-99/4a has a CALL CHAR command to redefine one ASCII character at a time. The first argument is the ASCII code and the second is the 8x8 map expressed as a series of hex digits. (This is how I learned hexadecimal back in elementary school. Good times!)


12

It needs to be sync-on-green capable (any good monitor should have this mentioned in the specs). But even then you may have issues, I have a few O2's and I have observed that sometimes one of my monitors (Dell U2410, SOG capable) really distorts the colors (towards green), replugging the cable solves the issue. I had no issues with an Octane with 13W3->VGA ...


12

Yes there are a lot of compensations in a CRT like: magnets counteracting background magnetic fields circuits counteracting curvature of CRT screen surface circuits counteracting different length of the beam (edges/center) "linearizations" of brightness (gamma correction) and probably much more I can not think of right now... But back to your question the ...


11

Maybe the most difficult task is to find a plug for the Apple AudioVision connector. Here is its pinout, taken from http://pinouts.ru/Video/audiovision_pinout.shtml , in case you find a suitable connector and want to do the wiring by yourself. 1 Analog audio ground 2 Audio input shield 3 Left channel audio input 4 Right channel audio input 5 Left ...


11

You probably should cut down the resolution to 512x512. I actually worked with a graphics processing system (Earthviews by DBA Systems with the added AIMS (Advanced Image Management System) software). It was designed in the late 1970s, which is just before the time frame you mention. It had two monitors. One was the primary, a serial terminal used for ...


10

Many OCS/ECS Amiga games use more than 32 colours. There are some cases of games using Extra Half Bright (EHB) mode like Universe (see this thread for more info on that game: How to obtain 256 arbitrary colors with limitation of 64 per line in Amiga (ECS)?). However, the most usual way of achieving more than 32 colours in a frame is using Copper tricks. ...


10

CRT in IBM 3279 terminal was capable of 640x480 at 72 Hz (p. 85 of maint. manual) in 1980. Relevant IBM SJ article ("Digital System for Convergence of Three-Beam High-Resolution Color Data Displays") is paywalled, and maintenance manual doesn't seem to mention CRT manufacturer; terminal itself sold over $1000 (via http://terminals-wiki.org/wiki/index.php/...


10

It wouldn't have been outside the realm of consideration at the time, but your guys would face threefold problems in terms of cost and practicality: As others have stated, the cost of DACs and other high speed circuitry with which to build the image out of memory, especially if you want to combine high horizontal resolution AND high vertical resolution AND ...


10

Yes they existed, and they were produced by Sega, with the interactive movie Time Traveler being the most common though Holosseum, an upgrade kit for Time Traveler, is probably the fighting game you are thinking of. It wasn't a real hologram, obviously, but just a 2d image projected via a concave dome-shaped mirror to give the appearance of floating in ...


10

Back in 1986, a company called Berkeley Softworks released a GUI desktop environment called GEOS for the Commodore 64. It was later ported to the Commodore 128, the Commodore Plus/4, and Apple II. GEOS was obviously inspired by the classic Mac OS desktop. It implements all the basic elements one would expect from such environment, such as a pointer-driven ...


9

Black-and-white hi-res from the 1040 STE on a VGA monitor should work with a direct connection and no tricky electronics at all (just the adapter cable) Atari VGA GND 13----X---- GND ---------4 GND Sense 4----+ +--------------2 green ...


9

Lots of homecomputers (or game consoles) had redefinable characters. Many game consoles (Atari, NES, SNES, Gameboy) are tile based in the first place, and a tile is nothing but a redefinable character. The Commodore 64 has a fixed charset in ROM, but can also use charsets in RAM. This tendency continued with the IBM PC, where graphics cards from EGA onwards ...


9

The monitor would be relatively easy to create. Just make the dot mask small enough, analog tubes can handle everything else – dirkt The problem is the sheer amount of circuitry required to generate this much graphics, or rather the price thereof. The Hercules monochrome graphics card came out in 1982 and was 720×348 for $500. – dirkt Tektronix ...


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