How low can you go, with RAM?

Is it possible to boot with only 48M of RAM in a DragonFly system?  Probably not.  128M would be better.  I usually talk about the lower memory limit for Hammer, since it’s so relatively low for a snapshotting file system, but the converse applies here.  128M is probably the comfortable lower limit, though it’s pretty hard to find a system that would limit you that way without doing it on purpose.  128M sticks of RAM are practically disposable these days, really.

Better MSI support

That’s Managed System Interrupts, for when your hardware is passing a lot of data and generating a lot of corresponding hardware interrupts.  MSI is what deals with all that traffic.  High-bandwidth (10G) network cards, for instance.  Anyway, Sepherosa Ziehau’s made more commits than what I’m linking to here, for support with various devices.

There’s many other MSIs out there, oddly enough.

Video and USB fix

Matthew Dillon has written a contiguous memory mapper, which is designed to fix problems with video cards and USB drives that need a big chunk of memory to keep.  This can affect booting or later on, when disconnecting/reconnecting a USB drive.  If this still doesn’t fix the problem for you, try adjusting the sysctl ‘vm.dma_reserved’ to something bigger, like 64M.  It defaults to 16M.

(Normal mailarchive isn’t updating because of an ongoing upgrade to crater.dragonflybsd.org – sorry!)

Lazy Reading for 2011/10/30

It’s snowing in the northeast U.S., which makes me happy!  Keep going, sky!

Unrelated link of the week: Manly Guys Doing Manly Things.  Most of the jokes revolve around games you may or may not know, with the occasional realistic experience that I’ve had myself.

GEM/KMS warning

Some newer laptops have Intel integrated video chipsets that require GEM/KMS to work well; they are supported by the vesa driver in X, but performance isn’t great.   Johannes Hofmann found this out the hard way.  GEM/KMS support is on the way for various BSDs, but it’s not here yet.  Just be aware of this if shopping for a new laptop in the next little while…