A new idea for expanded memory

[Kernal]

So it occured to me

what if we could some how expand the RAM via ape on the computer like make swap space on the host computer and some how route it to the atari...

also what programs could we write that would allow the atari to interact more with the host pc.

 

discuss.

[Mathy]

Hello Kernel

 

Any "ATARI 2 PC" connection would/could be just as fast (or slow) as any of the other SIO2... hardware (with the right firmware on the "..." side). Problem is, it's probably to slow. If you want to swap data to something outside the Atari that would be used as virtual memory, it would be better to use a parallel connection. Meaning something that connects to either the cartridge port or the PBI. At that point, it doesn't matter if the hardware connected to this port is a storage device (SD, CF, HDD, memory chips, etc.) or a PC/Mac.

 

Mathy

Edited November 5, 2011 by Mathy

[Kernal]

say we came up with an 3 gig swap drive interface with the atari

[Kernal]

i also mean expanding the ram available to programs via a swap drive on the pc thru the ape

[Creature XL]

i also mean expanding the ram available to programs via a swap drive on the pc thru the ape

I might understand you question wrong. However, do you have any idea how "swap space" works?

[Marius]

I don't see the benefit of this above the already existing memory upgrades. Anything through sio is far far far too slow, and anything that uses storage with a speed compared to the speed of modern SRAM and DRAM is useless for this too. A modernharddrive or flash storage is still too slow to be usefull.

 

Compare the speed of a ramdisk with a real harddisk or flash storage. The ramdisk wins and is much much much faster.

[Rybags]

6502 is not really any good for Virtual Memory, Multitasking or moving big blocks of memory around in a hurry for that matter.

 

VM can be implemented in a sense by a program selectively loading routines it needs, e.g. Alternate Reality.

 

The obvious storage device is a local high-speed one, but even then we're talking top speed of maybe a little over 100 K/second.

 

Another barrier is the Atari OS - it's memory management is too simple, but with the 6502's limitations it's not like it could have been done much better.

[flashjazzcat]

Compare the speed of a ramdisk with a real harddisk or flash storage. The ramdisk wins and is much much much faster.

On the A8, harddisks usually beat RAMdisks hands down. RAMdisks have to be buffered, while HDDs can transfer sectors directly. Try RWTEST on a RAMdisk under SpartaDOS X - it runs at just over a third of the speed of IDE Plus 2.0.

 

So really, even a PBI "virtual memory interface" for the A8 isn't going to beat a hard disk, since the hard disk can transfer just as fast as the 6502 can shift it.

Edited November 7, 2011 by flashjazzcat

[Marius]

@FJC

 

Ok... I created some confusion when I started about RAMDISKS. But it's impossible to create fast bank-switch effects with other storage than SRAM/DRAM chips. You are not going to do a fast 16K bankswitching simulation on a harddisk.

 

When the data is there ... in the right banks on your extended memory... you can do some very critical bankswitching. That is what a lot of demo's do when they need more than 64KB. The extra memory is most of the time not 'just storage' ...

 

I don't believe (not untill I have seen it) that a harddisk could replace the extra memory, when critical bankswitching is involved.

[flashjazzcat]

I don't believe (not untill I have seen it) that a harddisk could replace the extra memory, when critical bankswitching is involved.

Agreed! I was merely pointing out that a RAMdisk accessed via the SIO is generally somewhat less efficient than a hard disk.

[Shawn Jefferson]

We already have carts that give us 1024 KB+ of bank switched ROM. Add that to memory expansions (such as rambo, VBXE, etc..) and you have a lot of space for code and data. I'm using VBXE+1024MB Cartridge to port Moria over to the 8-bit.

 

Maybe it's better to think about what you want to do with the 8-bit, and then think about how to go about doing it. The largest hurdle is that the 6502 can only address 64k at one time, so that means a lot of bank switching for any memory intensive applications which gets complicated.