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scotty1024 · 11-01-2006, 05:35 AM

I think we're having some language issues here.

A true clock stopped "suspend" is never going to happen with DRAM.

DRAM consists of tiny little leaky buckets of electrons. If you don't go along the rows of buckets and inspect them and re-fill them they will leak down to no electrons and thus destroy their contents.

In normal high power operation the DRAMs are refreshed by the PXA-255 CPU. But in "deep sleep mode" the CPU can turn that responsibility over to the DRAMs and live out of its on board cache memory at a highly reduced clock rate of its own.

If iRex wanted to that could be using DRAM's with tighter testing specifications. The DRAM makers inspect their chips and those with the lowest leakage rate in their buckets get sold at a premium for use in devices that need the lowest of deep sleep states. DRAM with tightly picked specs can cut their onboard self-refresh rate way way way down. The normal refresh rates are selected to let the maximum number of devices operate stably. I've personally worked with DRAMs that were so low leakage they could go a minute at room temperature with no refresh and still have their contents remain intact.

The PXA-255 CPU itself is rated to drop its clock down to 33MHz and still be stable.

A "hibernate" to FLASH would indeed require a reboot. That doesn't make it impossible unless the device can't turn itself off. But with the 2.7 updater iRex showed the iLiad can do that.

The technical issues are where to get enough FLASH to hibernate to, there isn't enough onboard. So MMC, CF or USB stick. Well waking up USB stick to reocver from is not something one wants to code in a boot loader. So MMC or CF. So far though the MMC performance has been pretty slow. So then CF.

But how badly does iRex want to write a feature that only works with a 3rd party optional accessory?

Plus, as with sleep mode, there isn't any code to just go grab. Some clever person would have to code it just for the iLiad.

It could be very cool though. Suspend your iLiad onto a CF card, pull it out, put in a different CF card and resume from it. Suspend it again, put the other card back in... When tabbed readers become available this could be a very nice feature to have.

11-01-2006, 05:35 AM	#40
scotty1024 Banned Posts: 1,300 Karma: 1479 Join Date: Jul 2006 Location: Peoples Republic of Washington Device: Reader / iPhone / Librie / Kindle	I think we're having some language issues here. A true clock stopped "suspend" is never going to happen with DRAM. DRAM consists of tiny little leaky buckets of electrons. If you don't go along the rows of buckets and inspect them and re-fill them they will leak down to no electrons and thus destroy their contents. In normal high power operation the DRAMs are refreshed by the PXA-255 CPU. But in "deep sleep mode" the CPU can turn that responsibility over to the DRAMs and live out of its on board cache memory at a highly reduced clock rate of its own. If iRex wanted to that could be using DRAM's with tighter testing specifications. The DRAM makers inspect their chips and those with the lowest leakage rate in their buckets get sold at a premium for use in devices that need the lowest of deep sleep states. DRAM with tightly picked specs can cut their onboard self-refresh rate way way way down. The normal refresh rates are selected to let the maximum number of devices operate stably. I've personally worked with DRAMs that were so low leakage they could go a minute at room temperature with no refresh and still have their contents remain intact. The PXA-255 CPU itself is rated to drop its clock down to 33MHz and still be stable. A "hibernate" to FLASH would indeed require a reboot. That doesn't make it impossible unless the device can't turn itself off. But with the 2.7 updater iRex showed the iLiad can do that. The technical issues are where to get enough FLASH to hibernate to, there isn't enough onboard. So MMC, CF or USB stick. Well waking up USB stick to reocver from is not something one wants to code in a boot loader. So MMC or CF. So far though the MMC performance has been pretty slow. So then CF. But how badly does iRex want to write a feature that only works with a 3rd party optional accessory? Plus, as with sleep mode, there isn't any code to just go grab. Some clever person would have to code it just for the iLiad. It could be very cool though. Suspend your iLiad onto a CF card, pull it out, put in a different CF card and resume from it. Suspend it again, put the other card back in... When tabbed readers become available this could be a very nice feature to have.