768kB RAM on Generic Turbo XT

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Dulton
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Joined: Wed 05 Jun, 2019 12:11 pm

768kB RAM on Generic Turbo XT

Post by Dulton » Fri 12 Jul, 2019 12:02 pm

In the configuration window I can select 768kB RAM for a Generic Turbo XT.
Question: What happens to the 128kB above 640kB?

I have a Philips NMS-9100 Turbo XT with 768kB RAM. The extra 128kB is mapped to address range D0000-EFFFF and can be used by HIMEM.SYS for UMB.
Would love to see this in PCem as well and be able to LOADHIGH some TSRs :)

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omarsis81
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Re: 768kB RAM on Generic Turbo XT

Post by omarsis81 » Fri 12 Jul, 2019 2:34 pm

Dulton wrote:
Fri 12 Jul, 2019 12:02 pm
In the configuration window I can select 768kB RAM for a Generic Turbo XT.
Question: What happens to the 128kB above 640kB?
Can't it be used by HIMEM like you Philips?

Dulton
Posts: 12
Joined: Wed 05 Jun, 2019 12:11 pm

Re: 768kB RAM on Generic Turbo XT

Post by Dulton » Fri 12 Jul, 2019 2:58 pm

omarsis81 wrote:
Fri 12 Jul, 2019 2:34 pm
Can't it be used by HIMEM like you Philips?
Nope (or not yet), the last 128kB are not "visible".

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SarahWalker
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Re: 768kB RAM on Generic Turbo XT

Post by SarahWalker » Fri 12 Jul, 2019 4:24 pm

The extra 128kB should be accessible as conventional/base memory if you're using MDA/CGA/Hercules video. EGA/VGA and later will render it inaccessible.

Dulton
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Joined: Wed 05 Jun, 2019 12:11 pm

Re: 768kB RAM on Generic Turbo XT

Post by Dulton » Fri 12 Jul, 2019 4:35 pm

Ah yes, I understand now, thnx.
It's 64kB extra (not 128kB) which is simply added to the normal memory pool creating a total of 704kB. No (need for) upper memory blocks.

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