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Area 5150 for IBM PC 4.77MHz

On a whim I bought a CGA slice for the basket-case Convertible I have, but I haven't even plugged it in yet.
Funny I did as well. I would really like to fix that machine. Its just not on my priority list. I am a bit intimidated about the broken mechanisn in mine which is supposed to raise the keyboard when opened; mine does not.

I recently watched Cathode Ray Dudes video on the convertible. IT was a good video, but I feel he was overly critical on the computer.
 
I recently watched Cathode Ray Dudes video on the convertible. IT was a good video, but I feel he was overly critical on the computer.

I guess I haven't seen that, but to be honest, I have some pretty choice words about it. ;) It's kind of remarkable just how out of the way IBM went to make it difficult for anyone trying to make third-party expansions for it. Every other PC in the world uses one set of latches in front of the CPU to demux address and data, literally every removable part of the Convertible, even the memory cards, has a proprietary IBM ASIC on it that does both the demux and the address decoding. There is no reasonable technical explanation for this, it's 100% just making life more difficult for anyone trying to sell a cheaper replacement for the IBM part.
 
Tried someone this on IBM PC Convertible 5140? ;)

I've seen the results from a 5140 with the CGA 'slice' - it loses vertical sync often, and the really speed-sensitive parts just glitch out completely (the 3D objects, the Little Green Man 'wibble' effect, and the end credits).

It uses the Hitachi HD46505RP display controller, and judging by the sync issues, maybe it isn't fully MC6845-compatible despite popular wisdom. And the Convertible isn't cycle-exact vs. the 5150/5160 either (it's some 5% faster IIRC... check the TOPBENCH database). Probably the 80C88?
 
Unfortunately, it looks like the CGA card in the Kaypro 16 isn't completely compatible with Area5150 (works fine with 8088MPH). There's a few scenes where the screen scrolls to a solid white display, particularly on the following three scenes:

- Vertical Scrolling "houses": the first image is fine, but the second image and 4th image (with the "orb" that has scrolling text in it) are just solid white
- The diagonal scrolling text scene (after the lady with the fancy shades) alternates between the text display and a white box scrolling
- The ball rolling on the maze scrolls fine, but also alternates between the proper display and just white

I wonder if it's an issue with the memory or pages on the card? Not sure if it's fixable or any sort of a workaround?

-Chris
 
Ok so this is all i cant get on my 5140. It cant even start program. I tried IBM DOS 3.30 and also MS-DOS 6.22, same results. Floppy drive will remain ON, but nothing more happens..
 

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Ok so this is all i cant get on my 5140. It cant even start program. I tried IBM DOS 3.30 and also MS-DOS 6.22, same results. Floppy drive will remain ON, but nothing more happens..

The "CGA" emulation on the built-in video hardware of the 5140 is *extremely* barebones, I'm not surprised it faceplants that early. Anything that tries poking the CRTC registers will fail because, well, they're not there. It's basically "BIOS-compatible only" without the CGA add-on card.
 
Unfortunately, it looks like the CGA card in the Kaypro 16 isn't completely compatible with Area5150 (works fine with 8088MPH). There's a few scenes where the screen scrolls to a solid white display, particularly on the following three scenes:

- Vertical Scrolling "houses": the first image is fine, but the second image and 4th image (with the "orb" that has scrolling text in it) are just solid white
- The diagonal scrolling text scene (after the lady with the fancy shades) alternates between the text display and a white box scrolling
- The ball rolling on the maze scrolls fine, but also alternates between the proper display and just white

I wonder if it's an issue with the memory or pages on the card? Not sure if it's fixable or any sort of a workaround?

Those are the parts that use hardware scrolling and rely on the CGA framebuffer wrapping around after the first 16K. On a true CGA bit 14 of the address is "don't care", so reading B800:xxxx is the same as reading BC00:xxxx, and so on. It sounds like the Kaypro display board is decoding the full address, but since there's no actual video RAM above the 16K mark, all it gets from the bus are 'FF' values (which show up as white on screen).

I guess you could try a different CGA board (if this machine can handle one). Or you could locate the logic that performs the address decoding, and mutilate it as appropriate, but I'm not in any position to recommend this sort of thing. ;)
 
Personally, I appreciate the Area5150 for maximizing its 8088 CPU and IBM CGA.

However, if you are very disappointed, RAM: 512KB instead of 640KB Should have made it run on all IBM PC 5150 / 5160 / 5170

Nevertheless, the system requirements that must be met unconditionally for RAM: 640KB
This can be said to be a flaw in the program.

If you think badly, it has become impossible to enjoy 100% of all IBM PC original models.

Next time the Area 5150 is versioned or another program comes out, I hope you pay attention to these points so that you can run at least 512KB. 8088MPH to return to its own PCbooter if it is difficult to run in DOS Designing like this could be an alternative.
 
After installing MicroRAM Rev 1.2 to IBM PC 5150 or XT 5160, when Area 5150 is executed, it crashes irregularly in the middle.

My guess is that the issue is specific to MicroRAM Rev 1.2 and Rev. In 1.0 and 1.1, there is no crashing problem with Area 5150 at all.
Please refer to those using MicroRAM Rev 1.2.
 
There are a few reasons why we picked 640kB as our specification rather than some smaller amount of RAM. Most 5150/5160 machines in the wild have 640kB as it was a common upgrade to extend their useful lifespan, and ISA RAM boards are not rare. Although it was not a stock IBM configuration (and would have been prohibitively expensive in 1981) it could theoretically have been done even with the first 5150s (some early BIOSes have lower RAM limits but the demo can still use the RAM even if the BIOS doesn't know about it). But mostly because it's what people think of when they think of the earliest PCs - 4.77MHz 8088, CGA graphics, PC speaker, and 640kB. Any different RAM requirement would just cause more arguments about exactly what the RAM requirement should be. The demo is improved by being able to use 640kB (keeping the next effect in RAM so it's ready to go when the current one is finished). Though perhaps for the final version we could add a feature to automatically unload non-running effects to make it possible to run with less RAM (though some effects are quite memory heavy so even with that change it might not run in 512kB).
I'm not familiar with MicroRAM - is it hardware or software? If hardware, could it be malfunctioning? If software, what does it do? Area 5150 should be pretty resilient against other loaded software (as long as it doesn't take too much RAM) but it's possible to write TSRs/drivers that hook DOS/BIOS interrupts in a way that interferes with the demo. It does rely on DOS for disk access, so can't take over the machine completely.
 
The only hit for “MicroRAM” that I can find is yet another lo-tech 1MB card knockoff:


If stuff crashes with it installed it kinda sounds to me like someone needs to run an extensive RAM tester.
 
it's really not asking too much for these hobby PCBs to accommodate the mounting holes for a keystone mounting bracket, idk why so many don't
 
it's really not asking too much for these hobby PCBs to accommodate the mounting holes for a keystone mounting bracket, idk why so many don't

A number of PCB mills have special pricing for boards less than 100mm in both dimensions, and 100mm isn’t *quite* long enough to cover the slot and still reach the mounting bracket.

… which *kinda* works as an excuse when you’re prototyping something, but yes, it’s a piss poor way to go for something you’re selling.
 
it's really not asking too much for these hobby PCBs to accommodate the mounting holes for a keystone mounting bracket, idk why so many don't

Missing the point about the MicroRAM: "...can be plugged onto Monotech XT-IDE Deluxe v1.1 cards, combining the two to save an ISA slot". So this specific version's layout is meant to be a daughterboard as well as a standalone board.
 
Missing the point about the MicroRAM: "...can be plugged onto Monotech XT-IDE Deluxe v1.1 cards, combining the two to save an ISA slot". So this specific version's layout is meant to be a daughterboard as well as a standalone board.

But the broader point still stands, because there are a ton of these sorts of card designs being sold. FWIW, Monotech doesn’t appear to be currently selling the XT-IDE card this is supposed to clip to in Daughterboard mode, *AND* they also sell both an XT-CF card and a ROM card that likewise have no provision for being secured in their slots.

(* Edit: I guess they are selling the piggyback-ee card, the pictures haven’t been updated. Point remains about the other non-secure-able cards.)
 
Area 5150 to run on 3.5" 720KB diskette After running IBM DOS 3.20, the files were sequentially copied to a diskette and then dumped to a disk image. Rather than making it like some people like WINIMAGE, I made it to fit the practical skills even if it takes a little more time to enjoy the taste of the practical skills. One thing the Area 5150 lacks is the need to expand the RAM to 640KB as mentioned above, which is impossible in the early IBM PC 5150 unless the BIOS is changed, and in the case of the 5170, it is common to purchase an expansion RAM card to increase it by 128KB. It can't be a burden. Those who have XT / AT compatible models, most of them are 640KB, but those who have IBM PC 5150 / 5160 / 5170 are not many people who have 640KB as a percentage of the total. Especially those who have an initial 5150 can't increase it to 544KB at best. Unless you change the BIOS. So I would have liked it better if it worked even with 512 KB of RAM, but I am very disappointed in this part.
 
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