Messages in this thread | | | Date | Mon, 04 Nov 2002 16:30:11 -0600 | From | Eli Carter <> | Subject | Re: CONFIG_TINY |
| |
Rob Landley wrote: > On Monday 04 November 2002 20:34, Cort Dougan wrote: > >>I'm with you on that. People who clammer ignorantly about image size >>without looking at what they actually need should have opened their eyes in >>the last few years. Flash and RAM sizes under 32M are nearly unheard of >>now-a-days. > > > How much power does flash eat? I was under the impression half the reason for > tiny amounts of memory was to increase battery life in things that really > should last weeks or months instead of hours (wristwatches, cell phones on > standby, etc), but I guess that's mostly a question of dram and sram, not > flash. (I take it you can read the heck out of it without wearing it out, > it's just writes that are a problem... Then again you don't want rapidly > rewritten bookkeeping stuff in flash, do you? (Jiffies, scheduler stuff, > etc, should not be in flash...))
There a couple of kinds of flash memory that have different properties in the writes... The one I'm more familiar with allows you to change any '1' bit to a '0' bit on a bit-by-bit basis, but it is, ehm, a tad slow. But if you want to change a '0' bit to a '1' bit, you have to erase a 16 or 32 kB block to all '1' bits, and that is, well, very slow. (Storing 'jiffies' in flash, given that updating the jiffies would take multiple jiffies would be, well, 'fun'. ;) I could, however, see some sense in running the read-only parts of the kernel directly from flash...) It's been a while since I looked at read times, but I expect it to be essentially memory speeds.
> Not my area, I'm afraid... > > Rob
Just an FYI, in case you're curious.
Eli --------------------. "If it ain't broke now, Eli Carter \ it will be soon." -- crypto-gram eli.carter(a)inet.com `------------------------------------------------- ---------------------------------------------------------
Confidentiality Notice: This e-mail transmission may contain confidential and/or privileged information that is intended only for the individual or entity named in the e-mail address. If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution or reliance upon the contents of this e-mail message is strictly prohibited. If you have received this e-mail transmission in error, please reply to the sender, so that proper delivery can be arranged, and please delete the message from your computer. Thank you. Inet Technologies, Inc.
---------------------------------------------------------
| |