Ram

[Syko]

Gee! All this from one little bit...

Toni's absolutley right about the ram under JIT in UAE, he should know he wrote it! So please dont try to argue!

However I was talking about the fast RAM on my cyberstorm Mk II which is physicaly right next to the CPU, and has the highest priority of any RAM in the system.

As it is physicaly tightly coupled to the CPU, and there is no off-board access required it is the fastest RAM in the system for responce times and for susstained r/w access.

The same is true of any other accelerator RAM that is set up in the same way. Which is most of them..... Almost all Z3 RAM is set up in this way, appart from RAM which is on expansion cards - such as SCSI controllers.

The logical distribution chart which trodas is using makes no allowance for the physical location of the RAM, and thus makes no difference in it's speed of access.

And finaly..... for Paul who wandered into an ongoing argument/discussion/crash;

the A1200 has as standard 2MB of RAM, all of which is chip RAM, i.e. it can be accessed directly by the custom chips without the help of the CPU. As a result, this RAM is slower to respond to the CPU's requests.

Any expansion RAM is accessed faster than the chip RAM, because the CPU doesn't have to wait for the custom chips. Thus you get chip RAM and fast RAM, and that's why you have to have full chip RAM before you can have fast RAM. Just to really complicate things, there's 24bit fast RAM and 32bit fast RAM! So don't worry if you're still confused.

[trodas]

Syko - the fact that someone wrote something doest not guarantee that he is right
Your talking about CSMKII is right, but its not a "Z3 fastram" (this is a weird UAE terminology, call fastram Z3 fastram...) but a fastram, nothing else.
The "logical distribution chart" allow 128MB of space for fastram, you have to correctly interpret what "$08 000 000 - $10 000 000 = 32-bit Memory Expansion Space" means space for fastram, witch is sometime realy called a expansion memory space, so, its IMHO easily to understand.
...actually, i see that you are familiar with "expansion" term, so, i dont get why "my" chart dont allow space for fastram?!

And excourse me, but what do you mean with this: "that's why you have to have full chip RAM before you can have fast RAM"

[Syko]

Paul's trying to set UAE to A1200 spec, with 020 and AGA this means that untill the 2MB chip RAM is reached any other RAM added will not config correctlly, because the emulated/real hardware expects to find 2MB first, then any other RAM - Toni just made sure you cant screw the emu'd h/w by having less than 2MB chip before adding fast.

The logical distribution chart is any chart/diagram/listing that refers to the hardware organisation/hierarchy with a complete abstraction from the physical layer. It's my jargon, I invented it and find it usefull. If you do too, then please use it with my blessing.

[trodas]

Ah, that you mean!
Well, it can be, that OS 3.0+ Kickstart ROM for A1200 wont work correctly W/O getting 2MB chip ram first, but i wont bet on that.
Because i saw KS 3.1 into A500 with 512k chip ram as well, as working friend A4k with only 1MB of chipram - he lost the orginal 2MB simm and i find quite hard to get simm, what shows as 2MB (i end with 8MB simm, showing as 2MB of chipram - and no, the switcher allowing more chip ram on a4k mainboard wont work - eg. dont give me more )

So, altrought A1200 KS can be "hardwired" to 2MB chip, i wont expect that, even the chip ram is solded onboard and always there - since the very similar KS works with diferent combinations of HW (A3k has also 1MB of chip ram) and therefore it seems obivous, that expansion library detect wery correctly system friendly memory and dont seems to be tied with 2MB chip into any way.

Even the WinUAE with a1200 KS 40068 works for me with chipram settings at 256kBy fine - OS boot
...but it seems that either this option is broken, or A1000 with 256k of chip ram is not supported anymore, cause OS reporting 512k of chip ram
...so, maybe this is the limit, but certaingly not 2MB of chip.

Well, friend a4k also dont starting W/O chip ram
...since into chipram get after boot inicialized the expension library, so...

[andreas]

Originally posted by Syko
[B]Gee! All this from one little bit...

Toni's absolutley right about the ram under JIT in UAE, he should know he wrote it! So please dont try to argue!

No! It's Bernie Meyer who developed JIT, not Toni!

[Amiga1992]

Trodas: BOLLOX

[Syko]

No! It's Bernie Meyer who developed JIT, not Toni!

Please forgive me I'm an ideot but the idea still applies.

Because i saw KS 3.1 into A500 with 512k chip ram as well,

What I said applies to AGA chipset not OCS or ECS (AFAIK).

i end with 8MB simm, showing as 2MB of chipram - and no, the switcher allowing more chip ram on a4k mainboard wont work - eg. dont give me more

The 8MB switch on the A4000 mobo does work, BUT ONLY WITH AAA CHIPSET - and there's only 2 or 3 of those as prototypes in existance shame really, if someone could produce them for £50 retail I'd sell my mum for it. (AAA chipset supported 24bit VGA screens as well as PAL/NTSC - on seconed thoughts I'll chuck my dad in as well )