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Rainbow 100A Memory beyond 256K?

Hi Nicola -- That looks FANTASTIC! woohoo!

I took a quick look on ebay -- 18 pin dip 1m dram looks to be pretty rare -- mostly one-offs. If you find a listing you think good (what speed are you looking for -- slowest I saw in a quick scan was 100ns) I'm happy to contribute funds to the project in order to purchase -- I can send to you via paypal. Going forward, if the 1mbit dips prove to be unobtainable, what do you think? SMT chips?

Best, Alison
 
alitel said:
Hi Nicola -- That looks FANTASTIC! woohoo!

I took a quick look on ebay -- 18 pin dip 1m dram looks to be pretty rare -- mostly one-offs. If you find a listing you think good (what speed are you looking for -- slowest I saw in a quick scan was 100ns) I'm happy to contribute funds to the project in order to purchase -- I can send to you via paypal. Going forward, if the 1mbit dips prove to be unobtainable, what do you think? SMT chips?

Best, Alison
Click to expand...
Hi Alison,
thanks but funding is not necessary :)
No worry, UTsource have a huge stock of misc brand of 1Mbit mem.
I found the Hitachi HM511000AP-8 at $0.96 for each. You just need a little patience for shipping from China
 
na103 said:
Hi Alison,
thanks but funding is not necessary :)
No worry, UTsource have a huge stock of misc brand of 1Mbit mem.
I found the Hitachi HM511000AP-8 at $0.96 for each. You just need a little patience for shipping from China
Click to expand...
Hi Nicola -- OK sounds good! I see them on UTSource.
 
VERAULT said:
looks incredible. I have got to build one of these. If anyone is buying Pcbs can they sell me one?

Also https://github.com/na103/rambow unless I am typing it incorrectly its not working for me
Click to expand...
I will publish everything for free under CC license when I have tested the board.
I've already seen that there are things on the pcb that I need to fix.
Anyway, thanks for your interest and fingers crossed
 
na103 said:
I will publish everything for free under CC license when I have tested the board.
I've already seen that there are things on the pcb that I need to fix.
Anyway, thanks for your interest and fingers crossed
Click to expand...
Ya, I also tried the above web link on May 28 at 3:30 pm and had no luck with it either.
If not we might have to wait a while until this until it is working. Since I have read that NA103
wants to fix some things that they have seen on the pcb which likely/probably needs to done before the project is posted on github.com.
But, maybe in a couple of days from now the link will be working by then and the fixes done as well.
 
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good news!
it seems to works :)
any suggestion to test the whole memory area? the rainbow diagnostic software seems not to work correctly.
maybe a bios A limitation that does not recognize the memory correctly ?

1718464995459.jpeg1718465029560.jpeg
 
WOOOOO HOOOOO!!! You're a genius! That's so fabulous!

Did you end up using the 1mbit chips from UTSource? If so, I will go ahead and order some in preparation :)

Would it be worth investigating the procedure to update the 100A to be able to use 100B roms? (yet another daughterboard I think, can't recall offhand)? would that be an approach? Or do you think we're either a) fine, or b) we'll want to tweak the ROM code?

Best, A
 
alitel said:
WOOOOO HOOOOO!!! You're a genius! That's so fabulous!

Did you end up using the 1mbit chips from UTSource? If so, I will go ahead and order some in preparation :)

Would it be worth investigating the procedure to update the 100A to be able to use 100B roms? (yet another daughterboard I think, can't recall offhand)? would that be an approach? Or do you think we're either a) fine, or b) we'll want to tweak the ROM code?

Best, A
Click to expand...
yes i used the HM511000 DRAM buy from utsource.
i don't know of a mod that allows to use the roms (different in size and number) of the model B on A, probably a patch would be a auspicable solution.
at startup the 100A doesn't give any error, the bios system test is ok.
the only problem seems to be with the memory diagnostic software. Is not possible to do 8088 memory test because it reports an incorrect memory size.
in fact the 100A supports a maximum of 256kb with the option memory for 100A or 832kb with the adapter and option memory B.
in this case the RAMbow reaches 896kb.
anyway I think this is a non-problem if the operating system recognizes all the memory.
 
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na103 said:
any suggestion to test the whole memory area? the rainbow diagnostic software seems not to work correctly.
maybe a bios A limitation that does not recognize the memory correctly ?
Click to expand...
I correct myself, the message of incorrect size of memory is given with the original rainbow diagnostic software.
the memory test done with the B expansion memory software works correctly.
no problems detected. 🥳
I have tested MSDOS 3.10, 2.01, Word Perfect and CP/M-86/80 2.0, 2.10 and everything seems to work perfectly.

1718544958920.png
 
na103 said:
good news!
it seems to works :)
any suggestion to test the whole memory area? the rainbow diagnostic software seems not to work correctly.
maybe a bios A limitation that does not recognize the memory correctly ?

View attachment 1281586View attachment 1281587
Click to expand...
See NA 103 message from Today at 7:36 AM
A short note about an alternation solution to the 100A memory diagnostic diskette.
..
Ya some older versions of the rainbow diagnostic software even with a bios firmware patch installed will still not check the memory above 384K on a RB100A model.
Some versions of the Memory diagnostic test/Patch utility diskette for the 100B will run on the 100A, on these diskette I would only use the memory testing part of it to check the memory.
..
Since some of the rainbow diagnostic software where done in modular sections the disk could be updated. But normally I just use the 100B Memory diagnostic utility or a a 3Rd parity memory
check utility (,that supports memory locations from 128K to 896K) if the memory board is configured differently then DEC's models. 7 or 8 or 9 chips per row.
..
There where some other ones that where not hardware specificant that would work. Basically any one that does not do direct hardware calls to the refresh Controller, Interrupt Ctrl or DMA CTRL should work.
..
Anyways any Ideal of what early version of the rainbow 100A diagnostic software was tried (and/or its release date). (Just for the hell of it from NA 103 message today at 7:36 AM)
 
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na103 said:
yes i used the HM511000 DRAM buy from utsource.
i don't know of a mod that allows to use the roms (different in size and number) of the model B on A, probably a patch would be a auspicable solution.
at startup the 100A doesn't give any error, the bios system test is ok.
the only problem seems to be with the t. Is not possible to do 8088 memory test because it reports anrainbow diagnostic software.
in fact the 100A supports a maximum of 256kb with the option memory for 100A or 832kb with the adapter and option memory B.
in this case the RAMbow reaches 896kb.
anyway I think this is a non-problem if the operating system recognizes all the memory.
Click to expand...
Ya it is not really a problem, unless you get some bad chips. Then it could be a issue to diagnose the faulty chip (or chips).
As for the BIOS Firmware memory size error and the memory diagnostic software error it looks like a Bios Firmware fix would solve that issue and of course the Rainbows diagnostic software diskette should be patch to.
That's' if we want to be professional about it.
This is mostly a non-problem if the operating system recognizes all the memory without any faulty chips involved.
..
At one time there was a 3rd party Model B to Model A ROM adapter card, but now days most just modify the models B firmware ROMS to work with a 3 ROM solution installed in the 100A models. Yes they are piggybacked
firmware chips. Sorry but I have not cleaned up the Convert RB100 A to B Model. ZIP archive. But its internal text files are readable under the wordpad and related viewers, but some text editors will have issues reading them.
..
Just so you know their could also be other firmware issues if your Rainbow 100 has 3RD parity Controllers with on board BIOS firmware overlays that use the Memory expansion Connector bus.
Dec change the storage order in the Non Volatile memory for the 100B models so those cards firmware will have to be modified as well, unless the card is new enough to detect a 100A or 100B operation.
Mostly Network Cards, Smart Autobooting Hard Disk Controllers that use the Memory expansion Connector bus, can be affected.
 

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It theory some body could replace the 100A memory size restriction in the firmware BIOS by patch the 100B Models routeteen for it by simply replacing that section of coding. (Code size differences could be a issue).
 
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