Why did IBM create CGA - What user was there target?

[snowman]

Great discussion in the other EGA thread which I had started which raised another long time question of mine.
I used CGA until probably 1992/1993 iir!! Then I went straight to vga.

One of the comments in the EGA thread was how CGA was not for gaming. In "your" opinion ... what was CGA for? On one hand my first thought is that its incredibly limiting... but... for when it was introduced... it did have 80 column 16 color text mode. It also had 600x200 monochrome (yes 4 color 300x200 and 40 col text but the 4color mode was limiting and 40col text was largely unused/not on anyone's wishlist that I know of especially with 80col mode sitting there). Considering the graphics modes were pretty bad for gaming and the cga dot pitch was/is largely bad for text. Why did they create cga? What was their target demographic/user? MDA was for business, better text, better dot pitch. Soon after Hercules for great text and mono graphics that were arguably BETTER then cga.. so what was going on with CGA?? There were so many better choices at the time in my opinion. It became so popular too (again... I used it for YEARS mostly because thats just what I had/what my family bought until I replace it with vga in the early 90s). Do you feel people bought cga due to a misunderstanding of their options and its limitations? Ok cga did have composite 16 colors but again the sentiment here seems to be that it was not for gaming which I lean towards too. Why push out CGA besides, at the time, IBM not having any color option so they tossed CGA onto the scene because it seems like "nobody else would" from looking at past articles so they tossed cga out there. Seems like an afterthought and a quick punt out the door.

 

[sqpat]

I think you are overthinking this. The IBM PC was designed as a personal computer, for small businesses and home users. CGA was designed to provide color display. Other computers had color display at the time, too. You might as well ask who did they make a keyboard or a floppy drive for. It would have been a glaring feature gap.

IBM PC was not a big player in the PC gaming market until the 2nd half of the 80s. By the time IBM overtook apple II in game sales EGA and VGA already existed. This does not means that games targeted EGA and VGA graphics much - they were small parts of the market and expensive, so the most games targetted 640k or 256k of ram and CGA. Whether CGA was "designed for games" or not, there was a few years period where it was the minimum spec. Examples of this minimum spec stretch to 1993.

 

[krebizfan]

IBM APL used CGA to install the special characters needed since IBM didn't want to ship special character ROMs for MDA. That required CGA to have an 80 column mode. Unfortunately, IBM didn't realize that in time to modify the design to prevent snow.

IBM aimed to be a modest improvement over the Apple II and TRS 80. The preliminary IBM specification included all the Apple II graphics modes which are slightly worse than what IBM shipped.

 

[Zare]

Do you feel people bought cga due to a misunderstanding of their options and its limitations?

No, absolutely not. There was nothing limiting about CGA in its day. It was a good fit for the software.
Take a look at mobygames, browse for PC titles between 1981 and 1984. It's all simple stuff.

 

[Chuck(G)]

Unlike MDA, CGA was something that a home user could hook to a color TV. The crude character matrix pretty much said that this wasn't for office use.

 

[Zare]

what was CGA for?

Definitely not for "gaming".

As far as graphics is concerned, a 80s gaming platform has to have hardware sprites at least.

Only in 90s, has PC caught up with all the platforms such as home computers and consoles that have dedicated video hw.

If you go to mobygames, you can see that top games of 1984 are mostly text based, with graphics games coming along - quite static graphics.

It's easy to see PC as the top dog from today's perspective, even from perspective of early 2000s, but it was not so.
Neither CGA nor EGA nor VGA were associated with games on release.

All those videocards are used to directly drive pixels on screen from video memory.

 

[wrljet]

IBM APL used CGA to install the special characters needed since IBM didn't want to ship special character ROMs for MDA. That required CGA to have an 80 column mode. Unfortunately, IBM didn't realize that in time to modify the design to prevent snow.

IBM aimed to be a modest improvement over the Apple II and TRS 80. The preliminary IBM specification included all the Apple II graphics modes which are slightly worse than what IBM shipped.

CGA doesn't have soft font.

 

[Hugo Holden]

Unlike MDA, CGA was something that a home user could hook to a color TV. The crude character matrix pretty much said that this wasn't for office use.

I think that was the major marketing factor, the CGA signal was easily formed into an NTSC color composite signal suiting home color TV's, the H and V sync pulse timing was a close match. Even though the colors seen on a domestic TV did not exactly match what is seen on the IBM 5153 VDU, which are unique to it. IBM's CGA VDU also has the odd features that the intensity signal dynamically disables the contrast control, and the VDU is set up to create Brown as the low intensity yellow.

 

[krebizfan]

CGA doesn't have soft font.

Partial soft font. Only the upper 128 characters can be replaced. http://www.techhelpmanual.com/257-int_1fh__cga_graphics_character_font_pointer.html

 

[1944GPW]

Incredibly limiting? You are underrating the original IBM PC capabilities, it was very good for its time.

From the opening paragraph of the review in BYTE magazine, Jan 1982 Volume 07 Number 01 - The IBM Personal Computer:
"What microcomputer has color graphics like the Apple II, an 80-column display like the TRS-80 Model II, a redefinable character set like the Atari 800, a 16-bit microprocessor like the Texas Instruments TI 99/4, an expanded memory space like the Apple III, a full-function uppercase and lowercase keyboard like the TRS-80 Model III, and BASIC color graphics like the TRS-80 Color Computer? Answer: the IBM Personal Computer, which is a synthesis of the best the microcomputer industry has offered to date."

 

[the3dfxdude]

IBM built CGA because they wanted to compete for the home computer market where others also had color graphics.

 

[Eudimorphodon]

Partial soft font. Only the upper 128 characters can be replaced. http://www.techhelpmanual.com/257-int_1fh__cga_graphics_character_font_pointer.html

For clarity, that font table only applies when characters are being drawn by the bios routines in graphics mode. So… it matters critically in this argument how you define “soft font”. If you take it to mean “redefinable character sets for hardware text modes” then no, CGA doesn’t support “soft fonts” at all.

Incredibly limiting? You are underrating the original IBM PC capabilities, it was very good for its time.

Yes, this. I’ve kind of gotten sick of this tired premise that CGA was somehow unacceptably terrible simply because MDA had more pixels in its character set. Most of the early bellyaching around this came from people who expected that IBM’s $1,600 computer would magically be built to the same standards as their five figure terminal equipment, and later on it was all just people complaining that the thing designed in 1980 and now selling for peanuts wasn’t as good as stuff built three or four years later.

The *vast majority* of remotely affordable American personal computers around the time the PC was introduced were using NTSC frequency monitors, same as CGA, and the majority of those used the same non-interlaced progressive scan as CGA, limiting them to around 200 lines of vertical resolution. 8 lines per character cell was by far the most common configuration, so the fact that the descenders on CGA’s lowercase characters touch the tops of the uppercase characters on the line below was also par for the course… this whole thing is just BS.

In the positive column CGA had twice the horizontal resolution of an Apple II, it could display 80 column text from the factory, it had a rich 256 character text mode with graphics characters at least as good as Commodore had… it’s a *very competent* system if you judge it by the standards of the time. If it had any one single strike against it it’s that CGA *did* look pretty rotten (basically unusable) in 80 columns on a color composite monitor, and IBM didn’t sell a matching RGB monitor for almost two years, but this made it no worse than an Apple II with an 80 column card. The cheapest way to get into an IBM PC was actually to buy the CGA card and a *monochrome* composite monitor; this would save you a couple hundred bucks over an MDA and a 5151, and, well, sure, the display is blurrier with chunkier text, but it can still display graphics and play games, so it’s still arguably a better investment for a lot of people.

The fact that it was still the de facto base standard for PCs right up until XT class machines were no longer economically viable to sell around 1990 tells you all you need to know. It was “fine”.

 

[rmay635703]

It’s worth noting that when ibm released CGA there was no CGA Monitor.

Many of the early era correct games used composite color CGA which was better than the TTL monitor released later in terms of color at least .

Everyone remembers CGA after it was already dead and used as an entry level monitor with many clones not even correctly supporting composite color and also not properly supporting the various CGA pallets (AKA not fully IBM compatible)

 

[Eudimorphodon]

Many of the early era correct games used composite color CGA which was better than the TTL monitor released later in terms of color at least .

I mean, if you're talking about text mode it's no contest, the TTL monitor looks worlds better than composite color; the artifact colors aren't particularly "clean" and the palette is kind of weird. But sure, for graphics programs being able to do 16 colors (or more... or less, there's a lot of hairsplitting you start getting into as to what a "color" is when you're dealing with this way of generating color) on the composite monitor is a lot better.

That's why I'd say there's actually a really great happy medium between CGA and the later color standards, which is the IBM PCjr/Tandy 1000 "SuperCGA" modes... but again, that's comparing what was affordable in late 1980 verses 1984.

I think possibly the most notable thing about CGA that sets it apart from a lot of its competition was just how rich the attribute choices were in text mode. Using a full byte for character cell attributes and allowing both foreground and background to be set to any of the available colors was better than almost any other computer of the time. Usually "attributes" were limited to a single bit like reverse video, while the PC could do a ton of stuff with them(*). IBM was pretty smart how they made the use for character/attribute cells common between CGA and MDA; the latter supported underline, which CGA couldn't do, but you could just assign a color to mean underline in your word processor instead and nobody had a problem rolling with that.

(* For instance, the 160x100 16 color "graphics mode". Sure, it's chunky by today's standards, but again, look at the competition. An Apple II had a 280x192 graphics display, but it's effectively only 140x192 in six, not sixteen, colors, with some serious limits on which colors can be mixed in a single 7 bit character cell. CGA can run rings around that.)

 

[Zare]

One big thing I failed to read in the posts (maybe it was written) - PC was made as a cost-effective machine, no big expensive integrated chips.

Plantronics is one big red herring for the "CGA sucks" story. So immediately after CGA release here comes 320x200 16 colour capable two PCB card, which doesn't leave a dent on the market. Software support for it cheifly comes years later, and its all about graphics and bussines visualization applications, 0 games.

 

[Quagmire]

Incredibly limiting? You are underrating the original IBM PC capabilities, it was very good for its time.

From the opening paragraph of the review in BYTE magazine, Jan 1982 Volume 07 Number 01 - The IBM Personal Computer:
"What microcomputer has color graphics like the Apple II, an 80-column display like the TRS-80 Model II, a redefinable character set like the Atari 800, a 16-bit microprocessor like the Texas Instruments TI 99/4, an expanded memory space like the Apple III, a full-function uppercase and lowercase keyboard like the TRS-80 Model III, and BASIC color graphics like the TRS-80 Color Computer? Answer: the IBM Personal Computer, which is a synthesis of the best the microcomputer industry has offered to date."

Well, the 1000SX had most of that all in one package.

 

[sqpat]

Well, the 1000SX had most of that all in one package.

The 1000SX was a budget machine that came out in 1987, so it feels a little bit like apples and oranges anyway.

 

[cjs]

I think that was the major marketing factor, the CGA signal was easily formed into an NTSC color composite signal suiting home color TV's, the H and V sync pulse timing was a close match. Even though the colors seen on a domestic TV did not exactly match what is seen on the IBM 5153 VDU, which are unique to it. IBM's CGA VDU also has the odd features that the intensity signal dynamically disables the contrast control, and the VDU is set up to create Brown as the low intensity yellow.

It's an open question about whether that was really what was intended for CGA at the start, however, given that, as others have pointed out, that VDU wasn't released for more than a year after the CGA card was released.

The cheapest way to get into an IBM PC was actually to buy the CGA card and a *monochrome* composite monitor; this would save you a couple hundred bucks over an MDA and a 5151, and, well, sure, the display is blurrier with chunkier text, but it can still display graphics and play games, so it’s still arguably a better investment for a lot of people.

I doubt the the display was blurrier on a monochrome 15.7 kHz monitor; without the bandwidth limitations introduced by NTSC colour and the shadow mask or aperture grille used in colour monitors, it should have been quite clean, as it was on other systems such as the Apple II with an 80-column card. I have plenty of Japanese systems from about 1979-1983 that do 80-column text (and graphics, for that matter) at 640 pixel horizontal resolution and look great on a vintage cheap monochrome monitor; I can probably haul the stuff out if anybody's particularly interested in a photo of this.

In the meantime, here's an example of 80-column text in standard NTSC monochrome that I came across on the Internet. It's perfectly fine for the day. It's not as good as MDA, but MDA was particularly smooth and good looking, mainly due to its higher vertical resolution.

 

[cj7hawk]

It's kind of obvious...

Pie charts. Graphs. Bar charts. Line charts... All kinds of charts. At the time, business was just starting to use graphics to explain things, and some color is important for that. You don't need a lot - just enough.

Business Graphics were pretty obviously the reason, and that carried on with the EGA, since it was getting used for that.

CGA had the 80x25 text mode, but could also produce graphs and charts.

Games? Well they just naturally happened. There were LOTS of good CGA games. Sure, they lacked color, but so did the Sinclair Spectrum and most of the game detail on those was monochrome and in a lower resolution.

And of course, early flight simulators used CGA, and the rest is history.

Monochrome looked nicer, but there was no loss of characters in CGA. You could still read the screen.

And by the time VGA came out, memory was cheaper and expectations higher. Finally you could show a picture of something on the computer and it was good.

 

[Andrettigto]

….so what was going on with CGA?? There were so many better choices at the time in my opinion.

CGA was the the go to for anyone wanting APA graphics. It took some time before other options became available and there were compatibility issues.
Back in ‘81-‘82, 640x200 APA was pretty impressive. An hour later, you’d return to your PC and see that amazing plotted factual!