20

Most 8-bit computers implemented hardware text mode, and most of those used 8x8 fonts. This was logical for American computers; the title safe area on NTSC is about 200 scan lines; font height 8 gets you 25 text lines, which is the de facto standard. (Or use 192 scan lines for 24 text lines, the other candidate for de facto standard.)

But the title safe area on PAL is more like 250 scan lines. To get 25 text lines, an 8x10 font would be ideal. This would nicely fill the screen, and would also look better. (8x8 is not quite enough to make descenders look good.)

It seems to me that there is a curious absence of this being done.

For example, the PAL version of the Commodore 64, sticks to the 8x8 font, leaving large chunks of unused screen space at the borders. Okay, because the font size on that machine was intimately linked to the graphics modes, changing it would break the ability to import American games, which is a good reason for that design decision.

But the Commodore PET had no such graphical capability; changing the font could not possibly have upset anything, yet it kept 8x8 anyway. Maybe that was because Commodore figured a better-looking display wouldn't gain them enough extra sales to pay for the extra engineering effort; easier to just take the American design straight across.

Much stranger was the ZX Spectrum, which didn't even have hardware text mode, rendered everything purely bitmap, but used 8x8 anyway, using only 192 scan lines for 24 text lines.

The only 8-bit machine I know of to take advantage of PAL resolution was the BBC Micro, and that still stuck to 8x8 for its software bitmap fonts, giving 32 text lines, which at least is using the full resolution of the screen, though creates awkwardness if you want to port software across the Atlantic.

Did any European 8-bit computers use a 10-line font, either hardware or software, to take advantage of PAL displays? (Not counting the later GUI machines where fonts became arbitrarily resizable anyway.)

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  • 1
    Yes and no. Even late machines like the TA Alphatronic PC used 8 line characters with 24x40 or 36x80. Different may be the Siemens PC-D with 25x80 and 14 lines per row, but while it used a BAS (composite) signal, it's timing was for 350 lines and 60 Hz. Also, a 16 bit professional PC, not an 8 bit home computer.
    – Raffzahn
    Dec 16 '20 at 0:21
  • 2
    Modes 6 and 3 on the BBC use ten scans per line, they just happen to be 8 pixel-addressible lines plus two blank ones. But if you’re talking about fitting 25 lines to 250 scans, that’s just an implementation detail.
    – Tommy
    Dec 16 '20 at 4:23
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    As for the ZX Spectrum, the layout of the frame buffer is such that an 8x8 font is the most reasonable choice. And evidently a lot of thought went in to laying the frame buffer out that way
    – OmarL
    Dec 16 '20 at 7:15
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    @OmarL: Indeed, for ZX Spectrum details see retrocomputing.stackexchange.com/q/7274/10358 and retrocomputing.stackexchange.com/q/212/10358
    – Jonathan
    Dec 16 '20 at 8:56
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    It feels as if the core question here is less about larger character resolution, as that happened several times, but using that together with 24/25 line, which essentially makes this a question about computers using the higher resolution PAL provides, so over 200 visible scan lines, isn't it?
    – Raffzahn
    Dec 16 '20 at 13:08

11 Answers 11

15

Why is the question restricted to 8-bit computers? How would the bus or register width factor in that decision?

The Elektronika BK series used 256 scan lines and a 10-line font, subdivided into 24 text lines, 1 status line, and a divider/tabstop indicator area between them.

Screenshot

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    Right, it's not really about the bus or register width, more about the era of fixed fonts, as opposed to the later era of proportional and scalable fonts when the question becomes moot. But that is an interesting reference, thanks!
    – rwallace
    Dec 16 '20 at 0:40
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    I suppose its more important on a Russian computer because of chars like Щ and Й. Still, the Й on your screenshot looks kind of munched up
    – OmarL
    Dec 16 '20 at 7:11
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    @gerrit en.wikipedia.org/wiki/Vilnius_BASIC
    – Dan M.
    Dec 16 '20 at 14:34
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    @OmarL I'd imagine same should apply to the most of the Europe as well, since diacritics are not uncommon.
    – Dan M.
    Dec 16 '20 at 14:35
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    @OmarL It's a tradeoff. The baseline has to be high enough within the glyph area to allow for various descenders on lowercase letters, so there is not enough space for a disconnected diacritic on a capital letter. Unlike the accents, the breve on Й cannot be brought lower.
    – Leo B.
    Dec 16 '20 at 16:19
17

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 also had 10 pixels per text row.

Source: Mikrodatorns ABC

4
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    can you include a punktmatrise for Swedish characters Ä, Ö, Å?
    – OmarL
    Dec 16 '20 at 10:23
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    But did it display 24 lines in the 10 line mode?
    – Raffzahn
    Dec 16 '20 at 13:05
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    It had 24 rows of 40 characters. But it used a special made monitor, so the question is if it fits in this discussion.
    – UncleBod
    Dec 16 '20 at 13:29
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    There was a TV modulator box for the ABC 80 and its video output conformed to European TV norms, so I think it fits.
    – idrougge
    Dec 17 '20 at 13:12
16

Teletext — as seen in the BBC Micro's MODE 7 — used more than 8 lines for its font:

enlarged mode 7 text

(The line spacing in the image is incorrect, but to the best of my knowledge the pixel imagery is correct)

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    Which presumably means that whichever Philips it was with only an SAA5050 for video does the same. As did all teletext receivers.
    – Tommy
    Dec 16 '20 at 4:24
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    Mode 7 was 12x20, based on a 6x10 matrix. See beebwiki.mdfs.net/MODE_7 Dec 16 '20 at 8:42
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    @Tommy: I think you mean the Philips P2000T computer.
    – MSalters
    Dec 16 '20 at 11:26
  • Ah man.. the nostalgia. Dec 18 '20 at 16:46
6

It isn't European, but the Atari 8-bit range could do a ten-line character mode (IR mode 3, which looks like graphics mode 0 but with a little bit of extra line spacing), where the characters were still designed on an 8x8 grid but descenders (the last 32 characters) were padded by two blank lines at the top, with the rest padded with two blank lines at the bottom.

Obviously this isn't quite the same as a true 8x10 character mode, but it's an interesting data point I think.

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    Have you found any "real" programs that used mode 3? I have not, and it seemed a bit of a waste. Dec 17 '20 at 20:04
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    @MauryMarkowitz IIRC there was a word processor that used it, though I don't recall the name.
    – al45tair
    Dec 18 '20 at 21:21
5

The Videx Videoterm 80 column card for the Apple II (very different from the 80 column display on the Apple //e) used an 6845 that had a programmable character height (and width), with a maximum of 8x16 pixels for characters.

You could change the font by burning your own EEPROM, but the standard font was 7x9 (or 9x9 if you count spacing between characters) for 80x24 characters on a monitor.

Apparently at some stage they also offered a 7x12 (or 9x12) font for 80x18 characters, but this feature was then removed (the 80 column card I had didn't aloow this).

So it looks like your sentiment of "to get 25 text lines, an 8x10 font would be ideal" was not shared by everyone ... though you could have burned your own EEPROM to get such a font.

4

French Minitel (cocorico!) used a 8x10 font size. But it has its own screen, you couldn't connect an external PAL screen.

The Philips VG5000 also. This one was made to be connected to a TV through a peritel port.

In fact, both these use the SGS-Thomson EF9345 "graphic" chip. I suspect it was used by some other computers too, and I bet those would certainly all have a 8x10 font size: it is on the specs of the chip. See page 22, for example.

2

The Teletext standard, and the SAA5050 series character generators which supported it, were designed to provide a highly readable 40x25 text display on a PAL TV.

The electronics had to be simple and cheap enough to integrate into consumer TVs, but also found their way into some microcomputers. Teletext support was insisted upon by the BBC when sponsoring Acorn to build the BBC Micro, and was continued with the subsequent BBC Master and BBC A3000 (technically a member of the 32-bit ARM-powered Archimedes family). This allowed the BBC themselves to use BBC Micros to prepare broadcast graphics and Teletext screens accurately.

The SAA5050 implemented Teletext using a built-in 6x10 font bitmap, which was internally upscaled using a simple edge-smoothing algorithm for the purpose of providing an interlaced display. Other members of the SAA5050 family provided alternative character sets, most notably the SAA5055 which implemented ASCII instead of the Teletext character set.

After upscaling, the equivalent graphics resolution was effectively 480x500 pixels, corresponding to a 12x20 upscaled font bitmap. The pixels were not square, and the characters appeared noticeably wider than the numbers suggest, more similar to a 16x20 matrix of square pixels.

1

With the PAL-compatible 50Hz / 15.625kHz setting, it was even possible to get 288 visible scan lines, allowing for 24 text lines of 12 pixels height (not from your average modified TV set, but from a monitor).

At university, I used a programmable video card to subdivide these 24 lines one step further to get 72 "lines" of 4*8px cells. Each text position consisted of 3 cells, two with the upper and lower half of the glyph, and one gap cell. This gave the opportunity to move a glyph up or down by 1/3 of a line height.

I used this arrangement to support indices and exponents in a WordStar extension for scientific text.

But the character generator was still based on an 8*8 font, so this doesn't literally match the question.

1

The Nascom 1 and 2 computers used a 9-line font on a 256 scan-line display, but as their display hardware was implemented with 74xxx series logic chips simplicity was its main goal, so for ease of address calculation, the 9-line font was displayed with 7 blank lines between each character, meaning there were only 16 rows on the display.

1

The Sperry UTS-30 used a 10x16 font matrix on a 24 line by 80 column green screen. The UTS-60, a color variant, used a 9x15 matrix with the same screen dimensions. See Sperry UTS 4000 Universal Terminal System

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  • Sure that this a European system based on PAL type TV output, as asked for?
    – Raffzahn
    Dec 19 '20 at 1:10
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    @Raffzahn - I am quite sure that the UTS-30 was available in Europe. Its unclear to me whether the question was strictly for PAL (as suggested in the final paragraph) or more general (the title). Computers were not constrained to use either NTSC or PAL.
    – tdelaney
    Dec 19 '20 at 1:30
  • IMHO the core idea behind the question is about using the higher number of lines PAL offers. It wouldn't make any sense otherwise, as it's of course not only easy, but had been done countless times with professional European machines with larger character cells (as there were in the US) using their own display system, independent of any TV standard - the mentioning of a 'title safe' area gives as well a strong indicator here, as that only exists within a TV setup.
    – Raffzahn
    Dec 19 '20 at 15:14
1

The Sinclair QL used a 5x9 pixel matrix in a 6x10 character cell in monitor mode, ending up with a 85x25 character screen.

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