Talk:IBM 5550

Resolution and text modes
I think some confusion may have occurred here, and/or someone can't do maths.

Claim one: 1024x768 (1bpp) and 360x512 (2bpp) graphics modes, which seems strange; not 512x768 or 512x384 then? No 4bpp in the lowest resolution case? Also, that's damned high for 1982/83... the highest mode needs 96kb, if bitmapped (equal to 3/8ths of the entire standard memory), and the lowest 45kb, which is equal to or greater than the entire memory of many other computers (around 16 to 64kb at the time, commonly 32 or 48). Standalone CGA adaptors only had 16kb, MDA 4kb and Hercules an enormous 32kb... Essentially, it's 3x the memory and resolution of Hercules :-o

Claim two: 80x24 text mode (or as written, 24x80, which is what makes the "360x512" suspect), using characters "of 24x24 or 16x16 dots".

80 x 24 is 1920 pixels wide; 80 x 16 is 1280 wide; 24 x 24 is 576 pixels high, 24 x 16 is 384. Obviously, neither of these fit correctly in any way.

1024 / 80 is 12.8 pixels (so it could be 12px, or 13px with a bit of a stretch to 1040 wide?), 512/80 is obviously an even less convenient 6.4px per character, and 360/80 is an entirely unrealistic 4.5px wide. Alternatively, 1024 / 24px per character makes 42.67 chars, 512 makes 21.33, 360 makes just 15... 1024/16 is more realistic giving 64 characters across (or 32, or 22.5)

768 / 24 is 32 lines, which works more convincingly; 512 would be 21.33 lines and 360 again 15. 768/16 makes 48 lines, 512 makes 32 and 360 makes 22.5 ...

So could it maybe be that it has a 1024x768 monochrome hi-rez with 16x24 pixel characters, in a 64x32 matrix, and a *720*x512 4-colour medium rez mode (taking 90kb, 93.75% of the memory of hi-rez) with 16x16 characters in a 45x32 matrix? Possibly with a wide-character mode sacrificing a few pixels in hi-rez for 24x24 pixel characters (42x32 matrix, 1008x768...) and 24x16 characters in medium (30x32 matrix)?

The extreme being 16x16 in hi rez (64x48 chars) and 24x24 in medium (30x21 chars, 720x504 pixels)? And indeed a very stretched 12x32 character cell to squeeze 80x24 (or 85x24) into 1024x768?

It just doesn't make much sense otherwise... 193.63.174.254 (talk) 12:37, 12 June 2017 (UTC)

Competition outside of Japan.
In the chinese (Taiwanese) market IBM's 5550 computer family was soundly beaten by Acer-Multitech's DCS-570 workstations, which had more calligraphic characters (17k vs 11k for IBM) and all of them stored in the ROM, instead of diskette. The DCS-570 also supported 5 different input shorthand methods of varying difficulty and efficiency, versus just 1 for IBM. Because of this, the market role of Acer and its chip-making branch ALI was cemented early and they managed to survive to this day. 188.143.6.237 (talk) 10:13, 30 March 2021 (UTC)


 * Good! However, I could only find articles about the announcement of DCS-570. (New Scientist; 10 Jan 1985) I know a few keywords about Chinese computing history such as ETen Chinese System, but I have no reference to explain it. We need to know how the IBM 5550 was used in the Chinese and Taiwanese markets and how it was eclipsed by PC-based Chinese systems. Darklanlan (talk) 00:25, 31 March 2021 (UTC)

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