Quote:
Originally Posted by grond
Well, just like your 24bit graphics card is going to be super slow over an ISA bus. So we just rule that out.
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Wrong. I'm happy to accept it. I'm merely pointing out that it would be slow. I'm not discounting it from existence. It would be nice if you'd refrain from the habit of mischaracterising what I've written. It would save a lot of time having to correct you for being dishonest.
Also, it isn't like for like: Graphics chips mounted on cards is usual to this very day. In fact, that very practice of GPUs on daughtercards began the component style still maintained which we're used to in PCs on today. Graphics chips today are STILL mounted on cards and guess what? We all use them. Seems to have worked out ok.
It is however NOT the norm for RAM expansion. RAM expansion cards were and are typically plugged into DRAM sockets on the motherboard close to the CPU where they communicate along a fast, specially designated, RAM bus.
So, I'm not discounting it. What I am doing is pointing out that when you look at the product availability timeline there is currently no evidence I've seen which says the A3000 in its day was expandable, with hardware then available, beyond the 16MB claimed. Not with any method we've yet seen. Back then, not even with RAM on daughter cards. So, as far as RAM expansion goes then, high-end PCs, designed to be used as LAN servers, could be expanded up to 256MB, with RAM mounted into mobo DRAM slots, at the same time the Amiga could be expanded to 16MB (I'm happy to be corrected, provided you provide a document confirming your claim).
By the time the 256MB BigRAM boards were available, it was 2012, by 2012 PCs were in another league.
So, if we put product availability on a timeline according to when you could get it, then there is no time when you couldn't buy a PC with greater RAM expansion potential than the Amiga. Not with hardware actually available in its day. At least, none that I know of. There was still also a long time before 24bit graphics cards, of any kind, appeared on Amigas. So for your "slow" accusation, I counter with "non-existent". So your choice is (allegedly) slow 24bit graphics versus none at all.
Quote:
Originally Posted by grond
What? That's the first time I hear that. I don't know of any reason why the OS should have difficulties of managing 2GB of address space. I have an Amiga with 512MB of RAM, why should I not be able to address more than that?
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I take it you haven't bothered to look? That's a really effective way of not finding evidence for something: Look away. I'm here to look. I may not have seen something yet so I'm here willing to be shown things I wasn't previously aware of.
The source I am using is the same one as before: The Amiga Forever site which appears to have a competent explanation of RAM considerations, taking in both real hardware and special cases permissible under emulators. let's stick to what it says about the real hardware (unless you're ready to admit the most powerful Amigas currently run under PC emulation faster than the original hardware?).
"The maximum amount of Fast RAM is 8 MB on all systems except the Amiga 3000 and Amiga 4000, where it is 64 MB. This is a special case that is possible only with an emulated environment, as the physical motherboards could only be expanded by inserting memory chips up to 16 MB."
Briefly: 16MB was the most onboard RAM you could have on the original hardware of any Amiga.
"The total hardware memory space defined by the Amiga Zorro III expansion bus specification is 1792 MB. This is shared by RAM expansions, RTG video memory, and other peripherals. If for example an RTG display card has 128 MB of video memory, that has to be subtracted from the maximum address space."
Briefly: 1.75GB was the most RAM you could theoretically have on daughter cards attached to the original hardware of any Amiga.
This brings you up to a total of 1808MB of RAM, including RAM on RTG graphics cards, RAM on Zorro III daughter cards and RAM on the motherboard, all maxxed out.
It then goes on to say:
"The Amiga Autoconfig mechanism supports Zorro III RAM expansion boards with memory totals being an exact power of 2, between 64 KB and 1 GB. Originally, when physical RAM expansions featured at most 128 MB, the address space available to Zorro III expansion boards was documented as being 1024 MB (1 GB, from 0x40000000 to 0x7FFFFFFF). In an emulated environment, the entire Zorro III address space (1792 MB) can be configured. However, not all operating systems and applications can make use of this entire space"
Thereby implying 1GB (+16MB on the mobo, presumably) is the maximum realistic figure through real hardware. The remaining portion of the theoretical maximum RAM is available only through emulation.
"If you see Zorro devices "disappear" after increasing the RAM to more than 512 MB, it probably means that the operating system does not support Zorro expansion boards above the first GB of address space"
Essentially then, anything beyond the first 512MB of expansion RAM falls outside the documented first 1GB of system memory allocation, so software/hardware trying to connect through it may fail.
https://www.amigaforever.com/kb/13-111