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Author Topic: A2091 Ram Capacity??  (Read 1033 times)

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Offline DiskChrisTopic starter

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A2091 Ram Capacity??
« on: August 14, 2014, 09:23:32 PM »
I'm looking to put some ram on my a2091, which according to amigaresource would be 4x256k dip. However, the card has 16 sockets and a max of 2 MB...Wouldn't that be 4 MB of ram if each chip was 256k??
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Offline Oldsmobile_Mike

Re: A2091 Ram Capacity??
« Reply #1 on: August 14, 2014, 09:48:58 PM »
Has to do with some obscure and long-forgotten (except by some people on this board) conversion, kilobit vs kilobyte, etc.  I honestly don't remember anymore!  But the maximum ram capacity of that board when fully loaded is 2MB.  Sorry!  You might try adding a 32-bit accelerator, or a Zorro-II memory card, or one of those Kipper2K cards that fits underneath the processor, etc., if you want more.  :)
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Amiga 500: 2MB Chip|16MB Fast|30MHz 68030+68882|3.9|Indivision ECS|GVP A500HD+|Mechware card reader + 8GB CF|Cocolino|SCSI DVD-RAM
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Offline DiskChrisTopic starter

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Re: A2091 Ram Capacity??
« Reply #2 on: August 14, 2014, 10:47:47 PM »
Ah yes that makes sense....Can you mix manufactors and speeds? I'm kinda finding a few here and a few there....
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Offline aggro_mix

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Re: A2091 Ram Capacity??
« Reply #3 on: August 14, 2014, 10:52:22 PM »
Quote from: DiskChris;770909
I'm looking to put some ram on my a2091, which according to amigaresource would be 4x256k dip. However, the card has 16 sockets and a max of 2 MB...Wouldn't that be 4 MB of ram if each chip was 256k??


The chips are 256 kilobits, 4 bits wide. 1 byte = 8 bits so you'll need two chips to give 256 kilobytes.

Zorro II memory is 16 bits wide which means you'll have to add 4 chips in parallel (as they are 4 bits wide) 4x256x4= 256x16 = 512x8 (512 kiloBytes)
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Offline DiskChrisTopic starter

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Re: A2091 Ram Capacity??
« Reply #4 on: August 14, 2014, 10:58:09 PM »
Yeah I was thinking in bytes not bits....And I managed to find some which should work, but I can only get 5...Would I be able to get different manufactors/speeds in the future assuming they were 4x256k and at least 120ns??
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Offline Plaz

Re: A2091 Ram Capacity??
« Reply #5 on: August 15, 2014, 02:11:45 AM »
Quote from: DiskChris;770921
.Would I be able to get different manufactors/speeds in the future assuming they were 4x256k and at least 120ns??


It's possible to mix chips. I've used a few 2091's over the years and used anywhere from 80-120ns chips from different manufactures. Do some home work though and make sure pinouts and other specs match up as not to hurt your card or other chips.

Plaz
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