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General Category => Amstrad CPC hardware => Topic started by: Sonic on 21:57, 20 March 11

Title: Maximum RAM expansion
Post by: Sonic on 21:57, 20 March 11
Hi all, I'm just curious what might be the maximum amount of RAM for a CPC?
HERE (http://en.wikipedia.org/wiki/Amstrad_CPC#Memory) you can read under "memory" that the top amount of RAM will be an upgrade to 4MB.
However, HERE (http://en.wikipedia.org/wiki/FutureOS#Supported_Hardware) you can read that FutureOS has support for an expansion from 2MB up to 8MB of RAM with RAM7's RAM expansion.
So what do you think is possible to upgrade to?
Title: Re: Maximum RAM expansion
Post by: Devilmarkus on 22:04, 20 March 11
The easiest way is to upgrade up to 512k extra ram. (Then you get 576k in total)

All other ram expansions need a modification on the CPC's pcb.
And just, because 2 or perhaps 3 apps support 2 or 4 or more mb it's not worth the effort. (IMO)
Title: Re: Maximum RAM expansion
Post by: MacDeath on 23:01, 20 March 11
I see no point in having more than +512K... This is by far more than enough provided almost no software is greater than this.

Appart funny specialist stuff (Videos ?)... or some kind of virtual HDD...
Title: Re: Maximum RAM expansion
Post by: steve on 07:25, 21 March 11
MacDeath is the new Bill Gates, "576k should be enough for anyone". :laugh:
Title: Re: Maximum RAM expansion
Post by: Gryzor on 10:08, 21 March 11
But, guys, Sonic asked what is the possible max, not what you think is practical or worth it...
Title: Re: Maximum RAM expansion
Post by: Bryce on 10:24, 21 March 11
Ok, if that's the question, then the answer is: More than you could ever want. From a Hardware point of view, you could connect 12TB of RAM to a CPC if you used shifted registers to choose the banks :D But is it useful? I doubt it. (A seperate powersupply would probably be required to power the board though.

Bryce.
Title: Re: Maximum RAM expansion
Post by: Ygdrazil on 10:37, 21 March 11
Hi There

Lets stick to memory expansions that does exist!

I doubt that a maximum of 8mb is possible as stated on the FutureOS page!

http://www.cpcwiki.eu/index.php/RAM7_2Mb_memory_expansion (http://www.cpcwiki.eu/index.php/RAM7_2Mb_memory_expansion) Has a maximum of 2MB

http://www.cpcwiki.eu/index.php/CPC4MB (http://www.cpcwiki.eu/index.php/CPC4MB) Has a maximum of 4MB

Both memory expansions can not be attached at the same time as they use the same ports!

So the maximum memory attachable should be 4MB (yarek).
I don't know where 8mb comes from?  ;)

Regards,
Ygdrazil

Quote from: Sonic on 21:57, 20 March 11
Hi all, I'm just curious what might be the maximum amount of RAM for a CPC?
HERE (http://en.wikipedia.org/wiki/Amstrad_CPC#Memory) you can read under "memory" that the top amount of RAM will be an upgrade to 4MB.
However, HERE (http://en.wikipedia.org/wiki/FutureOS#Supported_Hardware) you can read that FutureOS has support for an expansion from 2MB up to 8MB of RAM with RAM7's RAM expansion.
So what do you think is possible to upgrade to?
Title: Re: Maximum RAM expansion
Post by: MacDeath on 16:48, 21 March 11
Depends wether you are talking about Bits or Bytes... ::)

Also, Kilo or Kibi ?
Title: Re: Maximum RAM expansion
Post by: steve on 17:22, 21 March 11
Quote from: MacDeath on 16:48, 21 March 11
Depends wether you are talking about Bits or Bytes... ::)

Also, Kilo or Kibi ?

This 'ibi nonsense is just to allow hard drive manufacturers to short-change customers by conning them into thinking they are getting what they asked for instead of the much smaller capacity that the manufacturer provides, the standards committee should never have allowed it, a kilobyte is 1024 bytes and as far as I am concerned, always will be and I will not use that criminal 'ibi nonsense.

The CPC can, as far as I am aware address 4MB ram + 4MB rom, which is where the 8MB came from, maybe ram can use the rom mapping.
Title: Re: Maximum RAM expansion
Post by: Sonic on 19:02, 21 March 11
Hi all, thanks for the answers. :)


So when using existing expansions it would be possbile to get 4MB RAM, but only about 576k are practical and easy to do. That's what I wanted to know, thanks. :)
Title: Re: Maximum RAM expansion
Post by: arnoldemu on 10:33, 22 March 11
Quote from: Sonic on 19:02, 21 March 11
Hi all, thanks for the answers. :)


So when using existing expansions it would be possbile to get 4MB RAM, but only about 576k are practical and easy to do. That's what I wanted to know, thanks. :)
I would say *most* software is aware of the dk'tronics type ram, and that has a max of 576k.
The others are extensions, and most software will probably not see or use it without modification.
But if you want to go for 4mb ram for the fun of it, then why not?
Title: Re: Maximum RAM expansion
Post by: Sonic on 23:00, 25 March 11
Quote from: arnoldemu on 10:33, 22 March 11
I would say *most* software is aware of the dk'tronics type ram, and that has a max of 576k.
The others are extensions, and most software will probably not see or use it without modification.
But if you want to go for 4mb ram for the fun of it, then why not?
I was just thinking... about using the cpc for a BBS. I was thinking about writing a BBS, so more RAM and possibly 6MHz (http://cpcwiki.eu/index.php/6_MHz_CPC) could be great for 2 or more connected users at the same time. :D
Possibly I will come back to this idea one day, I'm too busy right now because I started learning Pascal for another project.
Title: Re: Maximum RAM expansion
Post by: TFM on 23:40, 25 March 11
Quote from: Sonic on 21:57, 20 March 11
Hi all, I'm just curious what might be the maximum amount of RAM for a CPC?
HERE (http://en.wikipedia.org/wiki/Amstrad_CPC#Memory) you can read under "memory" that the top amount of RAM will be an upgrade to 4MB.
However, HERE (http://en.wikipedia.org/wiki/FutureOS#Supported_Hardware) you can read that FutureOS has support for an expansion from 2MB up to 8MB of RAM with RAM7's RAM expansion.
So what do you think is possible to upgrade to?

Well, 2008 I was in contact with a guy who wanted to create an RAM expansion of 64 GB. But since it takes years to fill it and since it wouldn't be compatible, the plans have been given up.

However I think up to 128 MB it would make sense - especially if the RAM is buffered, so you can use it as RAM-disc or so on.

Staying (relatively) compatible will lead you to an 8 MB barrier. However also additional registers (I/O) could be introduced to come around this problems.
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