Re: Hibernation
On Fri, 19 Nov 1999, Heather wrote:
>Heather:
>>>Would it be possible to use that under Dosemu+DOS so that you can force which
>>>partition is visible as "D:" then do it?
>>
>> Maybe. But unless you have really good backups you probably don't want to
>> try it. Just imagine the bios dumping 100M of data over your favourite file
>> system.
>
>The Magio is extremely clear on whether it can, or it cannot, hibernate. I
>do not believe that it would attempt any such thing.
You have more faith in your computer's BIOS than I have in mine.
>>>Comparing enough hibernation volumes, could someone create a linux mktpadswap?
>>>Maybe it could encompass or call ext2resize and mkdosfs, and do the whole
>>>task - carve off the right amount of diskspace for your ram, get it into the
>>>partition table, format it, and put the hibernate volume in there. Easy
>>>enough to get -blank- hibernate volumes, just scrap one and recreate it. (Too
>>>late for us, but we can save next year's crop of users.)
>>
>> Maybe. I think that the BIOS looks through the file system structures
>> though. It's the only explanation I know of for Thinkpads only supporting
>> 64M of RAM for hibernation to HPFS volumes...
>
>I didn't know about that limit - that sucks. That still doesn't make clear
>whether the limit is that the file be contiguous, or that it be on a formatted
>filesystem.
True. However I think that the limit is related to HPFS having allocation
bitmaps which refer to 16M of data. So they probably only have BIOS code for
looking through 4 allocation areas. If it was blocks on disk then it would
be no more difficult to support >64M for HPFS than for FAT.
>> >(Anybody here using swap-to-ramdisk tricks so they don't need linux swap
>> >space on disk at all? Then hibernating would capture your swap too.)
>>
>> Swap to ramdisk only makes sense on broken hardware (IE hardware where some
>> RAM is really slow).
>
>No... it makes sense if you care about speed... and for the fact that even
>if you have a Gig of RAM, you can't get rid of swap entirely without getting
>mired in molasses. [I am told that the code for dealing with a swapless
So you create a 1M partition for swap then. Using RAM as swap will not gain
you anything. At best it won't be used and will just be a waste of memory
that could otherwise be used for disk cache. At worst you will have programs
being paged to it which means copying data to/from the memory area which
wastes CPU time.
With 64bit memory it will take 512 reads and 512 writes to copy a 4K page of
memory. If the memory is 10ns then it'll be 10*1024 == 10240ns to copy the
page. That's 4096 clock cycles on a modern CPU.
>system is not real efficient.] Not that I've seen a laptop with a gig yet
>- but we tend to have slower CPUs overall, and we're more interested in
>making our expensive toy last longer, so maybe we would want all the speed
>improvements we can get.
Having slower CPUs also means that we need to conserve their power more too.
That means not using swap-to-RAM, putting plenty of RAM in the system (so the
CPU doesn't block on paging), and doing anything else reasonable to get
effective use of CPU power.
Currently I am using the Xserver-fbdev which can't take advantage of the
co-processed features of my video card and wastes CPU power and energy.
I plan to write a Neomagic FrameBuffer driver and then try and get the
xserver-fbdev co-prossing patches going (they apparently work well on Power
Macintosh).
>In theory any slimline drive should fit, I just haven't considered opening
>the case and doing that yet.
What I would like to see is a laptop that supports multiple hard drives.
RAID-1 on desktop features is starting to become common (it will become
especially common when the Raidtools2 stuff gets into the mainstream kernel).
I think that we need the same in laptops. Also for more serious use they
should sell laptops with support for 4 hard drives to run RAID-10.
>Mine is full at 96 Mb and if it were a little faster to hibernate it would
>be perfect.
>
>I don't do enough on my laptop to use it up anyway, though I sometimes blow
>past the original 32 Mb, so it was worth it to fill 'er up.
When you move to a journalled file system you may feel the need for more RAM.
Journalling does result in a larger working-set for the cache system...
>> The latest Thinkpads can now handle more than 512M. Mine is only 3 weeks old
>> and it's behind the times already!
>
>Keep chasing the bleeding edge, you'll fall off a cliff... :) I guess we'll
>see Gigs of RAM soon enough then.
I spend less money on laptops than most people spend on cars...
--
Electronic information tampers with your soul.
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