What is 1T-SRAM and in what way is it different from 'normal' SDRAM?

[Elledan]

On the page with technical details of the GameCube, the main memory is described as: "24 MB MoSys 1T-SRAM, Approximately 10ns Sustainable Latency".

What does this description mean and has anyone some details on how 1T-SRAM works?

Thanks in advance

P.S.: any other technical details/explanations on the components of the GC would be welcome as well.

[edit]: here's the page with the specifications of the GC.

 

[CTho9305]

I don't believe 1T sram is possible... you generally need 4 or 5 transistors per bit of storage in SRAM. Of course, maybe they aren't talking about transistors per bit, but rather a cas latency (?)

 

[Elledan]

Well, it's definitely possible, unless Nintendo et al. are all lying

 

[BurntKooshie]

CTho9305 -- PM told me (in another thread) that an SRAM cell can be done in 4t, but is usually done in 6t.

I know that the 1t cells have been mentioned many times for the GameCube, not that I understand it. I have just about zero understanding as to how the circuitry works in most aything

 

[Elledan]

Okay, BurntKooshie: what is 4t? And 6t?

Someone help me before I lose it

 

[BurntKooshie]

That's me being lazy, and probably incorrect, in describing "Four-transistor SRAM cells" and "Six-transistor SRAM cells"

 

[Elledan]

Thanks for the explanation

Now if only someone would explain to me the details on 1T-SRAM...

 

[CTho9305]

well, it is totally beyond me how you could store a state in a single transistor... maybe pm will share his insights.

 

[Sohcan]

MoSys 1T-SRAM is pretty cool stuff, even though it isn't technically SRAM...it uses one transistor and one capacitor per cell just like DRAM, but it is arranged logically similar to SRAM, and the column, row, and refresh operations are performed internally and hidden from the memory controller. They claim to be able to get random access times of 3ns, which is why it gets the name "SRAM." Since it has density close to that of DRAM, it can be manufactured in higher capacities than SRAM.

Here's their product page (check out the "MoSys Explains 1T-SRAM Technology" pdf half-way down the page).

 

[Elledan]

Thanks for that link, Sohcan

I downloaded the PDF and indeed, it's pretty cool stuff

Of course, the PDF provided mainly the usual marketing-talk, so I'm not certain what the real disadvantages of 1T-SRAM are, nor why we don't see this RAM technology in PC's.

 

[CTho9305]

ah, that clears it up
I see... it doesn't require refreshing which is why they call it SRAM. Does it allow for block transferring like SDRAM does?