Re: Why Images Bother People (or, at least me)

[P T Withington <address@hidden>]

On Friday, Jun 13, 2003, at 13:21 US/Eastern, Brent Fulgham wrote:

> This reminds me of an interesting question raised in Raskin's "The 
> Human Interface."  Why on earth doesn't the operating system consist 
> of an image that can be saved when you "shut down" and loaded when you 
> "start up", so that your boot time is as minimal as just mmapping the 
> image back into memory?  In this case your boot would consist of 
> loading a simple bootloader that could load the memory image, then 
> away you'd go.

That's exactly how the Lisp Machine worked.

Current O/S's simulate this with 'sleep' mode.

Windoze has some aberration where when your battery gets low, it wakes 
up and consumes all remaining battery power by attempting to write an 
image of your memory to disk, but usually fails by running out of juice 
first.

The Symbolics LispM had an enhancement where it used the VM hardware to 
detect which pages in your image had changed from the image you started 
with, so you could build an "incremental" image of just the delta's.  
The bootloader knew how to build a merged map from the base world and 
deltas so that you paged the right pages out of the right file.