n0p wrote on 2023-09-03, 08:24:
Biggest advantage of Book 8088 so far - that it's produced 😀
I've seen a lot of open-source "build yourself an XT projects" - but those require technical skills and (a lot of) time to make.
Yes, that's true. Some rather critical people (a bit like me, maybe) would consider it to be an rather unnecessary "e-waste", though. 😉
That reminds me of a recent hackaday.com article about a cheap, DSP-based AM-only radio.
One group found it to be great (the rose-coloured oldtimers of AM days), while the other one was upset because AM as such is useless,
rendering the radio obsolete (the real fun is on SSB and CW; AM stations on medium wave and short-wave have mostly died out in past 10 years).
Point was, that a slightly more expensive DSP of same family had said SSB support - so it was a wasted opportunity.
Edit: My apologies, I assume my wording was a bit poor again. I didn't meant to step on someone's feet. 🙁
What I mean, is, that with slightly different specs, the Book 8088 could be an actually useful item (not that Norton Commander in your pocket isn't cool).
Thing is, a real PC XT or Turbo XT in the business world used to have Hercules graphics (most popular choice) or EGA. Not basic CGA. That was kid's play.
So if that Book 8088 had *at least* Olivetti 640x400, Hercules (alternate res) 640x400, EGA Mono 640x350 or Hercules 720x348, it could be useful as a real DOS computer.
Just think of running compilers/IDEs (doing DOS programming on the road), astronomy programs, playing SimCity, machine control stuff etc.
Edit: Plantronics ColorPlus and Tandy graphics (TGA II) are of course equally worthy alternatives, I think.
They are "Super CGA" graphic systems, so to say. They feature the things so badly missed.
Edit: Just did the math. Technically, 512x256 in 16c (2 Bit) would fit into 32 KB, as well.
Too bad this resolution was never used on PC. It would have been much more balanced than 640x200 in 16c.
But IBM and the game industry were somewhat obsessed with 200 line modes, apparently.
From a purely technical point, resolutions with up to ca. 300 lines per field are manageable on an average 15 KHz CRT.
Anyway, that's a bit off-topic, maybe. It just came to mind when calculating minimum memory requirements for video standard.
Edit: Aw, I'm sorry, I got carried away again. I'm a bit too chatty. 😅
n0p wrote on 2023-09-03, 08:24:As for video card - CGA and IO in Book 8088 are already done with three CLPD chips.
Video RAM chip is 32K Hynix - so 4-bit (16 c […]
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As for video card - CGA and IO in Book 8088 are already done with three CLPD chips.
Video RAM chip is 32K Hynix - so 4-bit (16 colors) 320x200 screen is possible.
I wish i know anything about how those CLPD are programmed (there's a manual, but i would like to see a higher level one)
Newer version, as betamax80 pointed, has COM and LPT, so Covox is totally possible there.
Interesting, 32 KB was likely chosen because original CGA has a mirrored frame buffer (2x 16 KB). By simply providing 32 KB physically, no extra logic is needed here.
- In reality, CGA image data uses 16 KB only. Another possible use case would be 640x200 in 4 colours (2 bit), I think.
Even on a real IBM CGA, if it had 32KB and its memory address logic was "corrected" (no mirroring).
Speaking of memory expansion, 736 KB of memory are perfectly fine in a CGA system.
Many upgraded XTs and clones had 704 KB and more memory installed.
Having such a memory expansion makes up for the lack of the HMA (286+),
which DOS 5 and up used to store their stuff (DOS 2&3 were more lightweight and didn't need that so much).
It would also lower the need for having some UMBs to load drivers into.
Edit:
n0p wrote on 2023-09-03, 08:24:
Newer version, as betamax80 pointed, has COM and LPT, so Covox is totally possible there.
Thanks for the info! That's good news indeed! ^^ And if the CPLDs get an update, eventually, it would be awesome! 😁
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