Hot answers tagged

93 votes
Accepted

Why do PCs boot in 720x400 resolution?

This is historically not uncommon at all. Before starting an Operating System and initializing a graphics mode, your PC operates in the simplest display mode available, 80×25 text mode. The original ...
user avatar
  • 1,455
67 votes
Accepted

Why are a lot of monochrome computer monitors green?

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 ...
user avatar
  • 2,528
63 votes

Why didn't early color TV sets accept RGB input?

When colour television broadcasts began (1960s, in the UK; perhaps a little earlier in North America?) there weren't any local devices that customers might want to use. Broadcast TV was the only ...
user avatar
  • 1,392
60 votes

Why did early arcade games use vertical displays?

Having the display vertical reduces the width of the cabinet. This means that a game machine can be fitted into a smaller space in a pub/bar, or in an amusement arcade where machines are in rows you ...
user avatar
  • 649
37 votes
Accepted

Glitch in the display of a Mac SE/30

As comments on the question already suggest, it looks quite like an address fault when video memory is read. While the picture is not really great, I'd say: Blocks of 8 lines are visible, so it must ...
user avatar
  • 166k
35 votes
Accepted

Did arcade monitors have same pixel aspect ratio as TV sets?

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 ...
user avatar
  • 13.7k
35 votes

Why did computer video outputs go from digital to analog, then back to digital?

Early digital video outputs, like CGA, were not really akin to the later standards such as DVI and its follow-on's. The reason for using multiple lines to carry the different analog portions of the ...
user avatar
  • 56k
32 votes
Accepted

Square pixels and TV output

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 ...
user avatar
  • 1,373
30 votes

Which computers had redefinable character sets?

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. ...
user avatar
30 votes
Accepted

How can you connect an Amiga 500/600/1000/2000 to a modern monitor?

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), ...
user avatar
30 votes
Accepted

Why did the original Apple //e have two sets of inverse video characters?

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 ...
user avatar
  • 166k
29 votes

Why did Super-VGA offer the 5:4 1280×1024 resolution?

VGA's 640x480 mode was the first to offer square pixels and an exception among all VGA modes available (320x200, 640x200, 640x350 and 720x400 for Text). Square pixels weren't the standard back then. ...
user avatar
  • 166k
28 votes
Accepted

Proportional fonts on 8-bit computers

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 ...
user avatar
  • 27.3k
25 votes

Did any Amiga 500 games or programs (apart from paint programs) use more than 32 colours?

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 ...
user avatar
25 votes
Accepted

Blue and yellow stripes on the screen when loading from tape on ZX Spectrum

Actually, the screen stripes while loading from tape first occurred on the ZX-81 - Where they were a result of Sinclair's typical savvy nature - the display and the "EAR IN/MIC OUT" had to share a pin ...
user avatar
  • 27.3k
23 votes

Why did computer video outputs go from digital to analog, then back to digital?

Before VGA was invented, CGA RGBI used 4 wires to get 16 colors and EGA used 6 wires to get 64 colors on the cable. Add 3 more for sync signals and signal ground, and this won't be an issue, simple ...
user avatar
  • 16k
22 votes

What is the hex versus octal timeline?

Addressing the "why" part of the question - from my point of view as an assembly-code programmer on PDP-11 and VAX, the "standard" radix is most usefully chosen to match the instruction layout. PDP-...
user avatar
  • 27.6k
21 votes
Accepted

Besides the VIC-20 did any other micros have fewer than 32 columns available for text mode?

The BASIC Programming cartridge for the Atari 2600 displayed twelve characters per line. The RCA 1802-based VIP used bitmap graphics rather than having a "text mode" as such, but the typical ...
user avatar
  • 26.1k
21 votes

Why didn't early color TV sets accept RGB input?

Early colour TVs predated VCRs and home computers by many years. Even if it did not cost much, adding an RGB input would still be a cost for something that no one would use. However, it would have ...
user avatar
  • 1,812
20 votes
Accepted

Is it possible to use an Amstrad CPC464 with a modern monitor or TV

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 ...
user avatar
20 votes

Why did early arcade games use vertical displays?

(From the perspective of the electronics, that means the displays were drawn sideways.) Not necessary. There is no inherent reason for drawing sideways. A video circuit can easy be made for either, ...
user avatar
  • 166k
20 votes

What kind of television set would work with the Commodore 64?

TL;DR If you don't want to rely on an intermediate device, such as a "scan-doubler", then you need a screen that includes analog inputs and internal electronics capable of displaying a low-...
user avatar
  • 56k
20 votes

Why didn't early color TV sets accept RGB input?

Many TV designs up into the 1970s were so called live chassis designs, which used one leg of the mains input as a reference ground. This saved materials and weight - given some early color TVs used ...
user avatar
19 votes
Accepted

LCD Displays with the Intel 8080

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 ...
user avatar
19 votes

Was the picture area of a CRT a parallelogram (instead of a true rectangle)?

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 ...
user avatar
19 votes
Accepted

Did any computer allow overscan on a CRT monitor?

The Commodore Amiga (all models) had hardware support for overscan on CRTs. This was accessible to the user through the Preferences settings, as shown in the dialog panel below. The Preferences ...
user avatar
  • 56k
19 votes

What kind of television set would work with the Commodore 64?

Modern smart TVs may have analog inputs, but they are very "picky". They often do not work with older computers. My two Smart TVs cannot display even Amiga nor Atari ST, although they ...
user avatar
  • 5,152
19 votes

Did any European computers use 10-line fonts?

The ABC 80 computer used a 5×9 character matrix, each interspersed with one row and one column giving 6×10 pixels per character. The followup ABC 800 models followed teletext specifications and thus ...
user avatar
  • 520
18 votes
Accepted

Could some 200 line displays have been pushed to 240 lines?

If the monitor’s phosphor mask is fine enough to handle the increased vertical resolution, then the rest is mostly about timing, and typical components at the time were capable of handling a 20% ...
user avatar
18 votes

How long did plasma displays persist?

But apparently a plasma screen has the remarkable property that it does not need refresh, i.e. it doubles as its own video memory. This depends of course on design, as there are many ways a plasma ...
user avatar
  • 166k

Only top scored, non community-wiki answers of a minimum length are eligible