VOGONS


First post, by noshutdown

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is there a simple way to identify whether a ramdac is capable of 256colors or high/true color? or do we have to remember a list of model numbers?

Reply 1 of 8, by elianda

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I guess the simplest way is to look up the datasheet of the DAC.

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Reply 2 of 8, by BloodyCactus

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Youd have to look at the data sheet. A lot of early ramdacs that were just clones of the original INMos dac are all 6bit (18bit), later ramdac evolved to be full 8 bit (24bit). I have whole bunches of ramdac chips for a project I was trying to do.

When truecolour/hicolour was all the rage, ramdacs were pretty much internalised into the graphic chip.

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Reply 3 of 8, by Anonymous Coward

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Most of the 8-bit RAMDACs only do 256 colour, but some do hi and true colour modes as well. You typically need to look them up to verify what they support. I find that cards that have 16-bit and 32-bit RAMDACs almost always support 24-bit colour. They are usually easy to identify because they have a very high pin count. The best RAMDACs are typically those that are blue with the exposed cores.

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Reply 4 of 8, by noshutdown

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BloodyCactus wrote:

When truecolour/hicolour was all the rage, ramdacs were pretty much internalised into the graphic chip.

true, most late isa video cards have integrated ramdac. especially i don't see many cirrus cards with external ramdac.
but there are some exceptions. tseng for example was very late to get ramdac integrated. trident used to be the cheap dog but they gave up isa rather early, all their cards newer than 9000 series don't seem to have isa versions, which meant their old 8900 and 9000 series remained in production for pretty long. most of 9000 series have integrated ramdac but 8900 series don't.

Reply 5 of 8, by Jo22

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I'm curious, what's the benefit of a high/true colour DAC on an ISA card ?
OK, back in the day it was useful for image manipulation, desktop publishing, etc.
But that was when these cards were still used for business related tasks.
I for one like to use the 256 colour depth, since it allows neat tricks like palette cycling. :)
That's neat for both DOS fractal programs, as well as Windows 3.x gaming.
The Windows 3.1 help also doesn't like stuff beyond 8-Bit.
The green hyperlinks become gray with anything higher.

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Reply 6 of 8, by chrisNova777

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ive got the cardinal 732A VGA in my 386dx40.. its supposedly got a 32768 clor "SIERRA" RAMDAC

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Reply 7 of 8, by alvaro84

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Anonymous Coward wrote:

The best RAMDACs are typically those that are blue with the exposed cores.

They also look awesome!

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Reply 8 of 8, by Anonymous Coward

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When it comes to 8-bit RAMDACs on ISA cards, I find the ones that support 32k colour are typically the "Sierra" type, while the true colour ones are often (but not always) the BrookTree "BT" type. Towards the end, almost all low-end VLB cards supported 24-bit colour using 8-bit RAMDACs, and they had many types.

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