94
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 ...
- 1,463
69
votes
Accepted
Why did older computers and OSes use UPPER case instead of lower case?
TL;DR: Upper Case Is the Default for Latin Script.
Latin script is based on upper case and designed around that. Lower case is a later add-on (see below) for cursive. Default use-case for Latin script ...
- 232k
65
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 ...
- 1,686
62
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 ...
- 679
38
votes
Accepted
What did Windows 2 do about varying aspect ratio?
Most of Windows’ display model is device-independent, or at least provides all the information required to produce consistent displays, and it’s the display drivers that handle discrepancies. As a ...
- 127k
37
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 ...
- 15.4k
36
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 ...
- 232k
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 ...
- 61.2k
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 ...
- 3,687
32
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), ...
- 17.6k
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. ...
- 18.9k
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 ...
- 232k
30
votes
Accepted
Why did IBM PC have horizontal cursor instead of vertical or block cursor?
The horizontal-line cursor was standard on the video terminals I used. The DEC VT50/VT52 series of terminals had only an horizontal-line cursor. The VT100 (and, I assume, subsequent terminals) had a ...
- 37k
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.
...
- 232k
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 ...
- 36.4k
27
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 ...
- 36.4k
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 ...
- 35.7k
23
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 ...
- 2,173
23
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 ...
- 5,782
23
votes
Why did older computers and OSes use UPPER case instead of lower case?
I would venture to say that it stems primarily from the telegraph tradition, starting with Baudot (1870s) which eventually led to ITA2. Essentially 5 and 6 bit codes (arguably a 5-bit code with a ...
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-...
- 37k
22
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 ...
- 38k
21
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, ...
- 232k
20
votes
Accepted
CP/M in fewer than 80 columns
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 ...
- 232k
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 ...
- 291
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 ...
- 5,585
19
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-...
- 61.2k
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 ...
- 530
19
votes
Why did IBM PC have horizontal cursor instead of vertical or block cursor?
TL;DR:
Available Hardware + Capabilities + Compatibility + User Expectation
Text mode cursor on PC Hardware allows only a full character cell width cursor that may cover any amount of a character cell ...
- 232k
18
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 ...
- 61.2k
Only top scored, non community-wiki answers of a minimum length are eligible